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Pneumonia

WHAT IS PNEUMONIA?

Pneumonia is an inflammation of the lung caused by infection with bacteria, viruses, and other organisms. Pneumonia is usually triggered when a patient's defense system is weakened, most often by a simple viral upper respiratory tract infection or a case of influenza. Such infections or other triggers do not cause pneumonia directly but they alter the mucous blanket, thus encouraging bacterial growth. Other factors can also make specific people susceptible to bacterial growth and pneumonia.

Defining Pneumonia by Locations in the Lung

Pneumonia is sometimes defined in one of two ways according to its distribution in the lung:

Lobar Pneumonia (occurs in one lobe of the lung).
Bronchopneumonia (tends to be patchy).

[For a description of the lung , see Box The Lungs.]

Defining Pneumonia by Origin of Infection

Pneumonia is often classified into two categories that may help predict the organisms that are the most likely culprits.

Community-acquired (pneumonia contracted outside the hospital). Pneumonia in this setting often follows a viral respiratory infection. It affects nearly 4 million adults each year. It is likely to be caused by Streptococcus pneumoniae, the most common pneumonia-causing bacteria. Other organisms, such as atypical bacteria called Chlamydia or Mycoplasma pneumonia are also common causes of community-acquired pneumonia.
Hospital-acquired pneumonia. Pneumonia that is contracted within the hospital is called nosocomial pneumonia. Hospital patients are particularly vulnerable to gram-negative bacteria and staphylococci, which can be very dangerous.

Disease Process Leading to Pneumonia

Infectious agents reach the lungs and cause pneumonia through different routes:

Most often, organisms that cause pneumonia enter the lungs after being inhaled into the airways.
Sometimes the normally harmless bacteria present in the mouth may be aspirated into the lungs, usually if the gag reflex is suppressed.
Pneumonia may also be caused from infections that spread to the lungs through the bloodstream from other organs.

Under normal circumstances, however, the airways that take air in and pass through the upper part of the body have very effective mechanisms that protect the lung from infection by bacteria and other microbes.

Large particles are first filtered out in the nasal passage.
When smaller particles are inhaled, sensors along the airways trigger coughing or sneezing reflexes, which force many particles to back out.
Tiny ones that are able to reach the bronchioles are trapped in a mucous blanket and are then moved up and out of the lungs by the beating movements of tiny hair-like cells called cilia, a mechanism known as the mucociliary escalator.
Bacteria or other infectious agents that evade the airway defense system are attacked in the alveolar sacs by defenders from the body's immune system, particularly macrophages, large white blood cells that literally eat foreign particles.

These strong defense systems normally keep the lung sterile. If these defenses are weakened or damaged, however, bacteria or other organisms, such as viruses, fungi, and parasites, can gain the upper hand, producing pneumonia.

The Lungs

The lungs are two spongy organs surrounded by a thin, moist membrane called the pleura. They are the largest organs in our body. Each lung is composed of smooth, shiny lobes; the right lung has three lobes and the left has two. Approximately 90% of the lung is filled with air and only 10% is solid tissue.

When a person inhales, air travels through the following pathways into the lungs.

Air is carried from the trachea (the windpipe) into the lung through flexible airways called bronchi.
Like the branches of a tree, bronchi divide successively into over a million smaller airways called bronchioles.
The bronchioles lead to grape-like clusters of microscopic sacs called alveoli.
In each lung of an adult there are millions of these tiny alveoli, which are composed of a thin membrane through which oxygen and carbon dioxide pass to and from capillaries.
During deep inhalation, the elastic alveoli unfold and unwind to allow this passage to occur.
Capillaries, the smallest of our blood vessels, carry blood throughout the body.
Red blood cells contain factors that fight pollutants; white blood cells are the critical infection fighters in our body.

WHAT CAUSES PNEUMONIA?

Bacteria are the most common causes of pneumonia, but these infections can also be caused by other microbial organisms. It is often impossible to identify the specific culprit.Bacteria

Many bacteria are categorized by the staining procedure used to visualize bacteria under a microscope. The stains determine if they are gram-negative or gram-positive bacteria. This gives the physician an idea of the severity of the pneumonia and how to treat it.

Gram-Positive Bacteria. These bacteria appear blue on the stain. The following are common gram-positive bacteria:

The most common cause of pneumonia is the gram-positive bacterium Streptococcus pneumoniae (also called S. pneumoniae or pneumococcal pneumonia ). It was thought to cause 95% of community-acquired bacterial infection, but research now indicates it is far less, accounting for about half of all cases. (Some studies suggest it may account for even fewer, 10% to 30% of cases.)
Staphylococcus aureus , the other major gram-positive bacterium responsible for pneumonia, accounts for about 10% of bacterial cases. It is one of the main causes of pneumonia that occurs in the hospital (nosocomial pneumonia). It is uncommon in healthy adults but can develop about five days after viral influenza, usually in susceptible individuals, such as people with weakened immune systems, very young children, hospitalized patients, and drug abusers who use needles.
Streptococcus pyogenes or Group A Streptococcus.

Gram-Negative Bacteria. These bacteria stain pink . Gram negative bacteria are common infectious agents in hospitalized or nursing home patients, children with cystic fibrosis, and people with chronic lung conditions.

The most common gram-negative species causing pneumonia is Haemophilus influenzae (generally occurring in patients with chronic lung disease, older patients, and alcoholics).
Klebsiella pneumoniae may be responsible for pneumonia in alcoholics and in other people who are physically debilitated.
Pseudomonas aeruginosa is a major cause of pneumonia that occurs in the hospital (nosocomial pneumonia). It is common in pneumonia patients with chronic or severe lung disease.
Moraxella catarrhalis is found in everyone's nasal and oral passages. Experts have identified this bacteria as a cause of certain pneumonias, particularly in people with lung problems, such as asthma or emphysema.
Neisseria meningitidis is one of the most common causes of meningitis (central nervous system infection), but the organism has been reported in pneumonia, particularly in epidemics of military recruits.
Other gram-negative bacteria that cause pneumonia include E. coli (a cause in newborns), Proteus (found in several damaged lung tissue), and Enterobacter.

Atypical Pneumonia

Atypical pneumonias are generally caused by tiny nonbacterial organisms called Mycoplasma or Chlamydia pneumoniae and produce mild symptoms with a dry cough. Hospitalization is uncommon with pneumonia from these organisms.

Mycoplasma pneumoniae ( M. pneumoniae ) is the most common nonbacterial pneumonia. Mycoplasma is a very small organism that lacks a cell wall. It spreads from prolonged, close contact and is most often found in school-aged children and young adults. The condition is usually mild and is commonly known as walking pneumonia. Estimates of its prevalence in community acquired pneumonias in adults range from 1.9% to 30%. In one study, it accounted for over a third of pneumonia cases in children.
Another small non-bacterial organism, Chlamydia pneumoniae ( C. pneumoniae ), is now thought to cause 10% of all community-acquired cases of pneumonia. It is most common in young adults and children, where it is usually mild. In one study, it was the cause of 14% of cases in a group of children with pneumonia. While less common in the elderly, it can be very severe in this population.
Legionnaire's disease, first diagnosed in 1976, is caused by the organism Legionella pneumophila, and is acquired by breathing droplets of contaminated water. Outbreaks have most often been reported in hotels, cruise ships, and office buildings where people are exposed to contaminated droplets from cooling towers and evaporative condensers. They have also been reported after exposure to whirlpools and saunas. Legionella is not passed on from person to person, but it may be much more common than once thought. Some experts even believe it causes 29% to 47% of all pneumonia cases. ( Legionella is sometimes categorized as an atypical pneumonia.)

Viruses

Viruses that can cause or lead to pneumonia include influenza, respiratory syncytial virus (RSV), herpes simplex virus, varicella-zoster (the cause of chicken pox), and adenovirus. Outbreaks usually occur between January and April.

Influenza is associated with pneumonia directly or by altering the mucous blanket and making a person susceptible to bacterial pneumonia.
Respiratory syncytial virus (RSV) is a major cause of pneumonia in infants and people with damaged immune systems. Studies indicate that RSV pneumonia may also be more common than previously thought in adults, especially the elderly.
Adenoviruses have been implicated in about 10% of childhood pneumonia.
In adults, herpes simplex virus, adenoviruses, and varicella-zoster (the cause of chicken pox) are generally causes of pneumonia only in people with impaired immune systems.

Aspiration Pneumonia and Anaerobic Bacteria

The mouth harbors a mixture of bacteria that is harmless in its normal location but can cause a serious condition called aspiration pneumonia if it reaches the lung. This can happen during periods of altered consciousness, often when a patient is affected by drugs or alcohol, or after head injury or anesthesia. In such cases, the gag reflex is diminished, allowing these bacteria to enter the airways to the lung. These organisms are generally different from the usual microbes that enter the lung by inhalation. Many are often anaerobic (meaning they can live in the absence of oxygen).

Opportunistic Pneumonia

Impaired immunity leaves patients vulnerable to serious, even life-threatening, pneumonias known as opportunistic pneumonias. They are caused by microbes that are harmless to people with healthy immune systems. Infecting organisms include the following:

Pneumocystis carinii, an atypical organism that is very common and generally harmless in people with healthy immune systems.
Fungi, such as Mycobacterium avium.
Viruses, such as cytomegalovirus (CMV). AIDS is a major risk factor for opportunistic pneumonia, as are other conditions including lymphomas, leukemias, and other cancers. Long-term use of corticosteroids and other medications that suppress the immune system increase the susceptibility to these pneumonias.

Occupational and Regional Pneumonias

A number of people are exposed to pneumonia-causing organisms specific to particular occupations or regions.

Workers exposed to cattle, pigs, sheep, and horses are at risk for pneumonia caused by anthrax, brucellosis, and Q fever.
Agricultural and construction workers in the Southwest are at risk for coccidioidomycosis, and those working in Ohio and the Mississippi Valley are at risk for histoplasmosis.
Workers exposed to pigeons, parrots, parakeets, and turkeys are at risk for psittacosis.
Exposure to chemicals can also cause inflammation and pneumonia.
Hantavirus causes a dangerous form of lung disease and is carried by rodents, but is still rare. It does not appear to be contagious; cases have occurred in New Mexico, Arizona, California, Washington, and Mexico.
People in the southwest are also exposed to the fungus Coccidioides immitis , the cause of Valley fever, which is a lung infection that can cause pneumonia in susceptibl e indivi duals.

WHAT ARE THE SYMPTOMS OF PNEUMONIA?

Symptoms of Common Pneumonias

General Symptoms.

The symptoms of bacterial pneumonia develop abruptly and may include chest pain, fever, shaking, chills, shortness of breath, and rapid breathing and heart beat.
Symptoms of pneumonia indicating a medical emergency include high fever, a rapid heart rate, low blood pressure, bluish-skin, and mental confusion.
Coughing up sputum containing pus or blood is an indication of serious infection.
Severe abdominal pain may accompany pneumonia occurring in the lower lobes of the lung.
In advanced cases, the patient's skin may become bluish (cyanotic), breathing may become labored and heavy, and the patient may become confused.

Symptoms in the Elderly. It is important to note that older people may have fewer or different symptoms than younger people have. An elderly person who experiences even a minor cough and weakness for more than a day should seek medical help. Some may exhibit confusion, lethargy, and general deterioration.

Symptoms of Pneumonia Causes by Anaerobic Bacteria

People with pneumonia caused by anaerobic bacteria such as Bacteroides, which can produce abscesses, often have prolonged fever and productive cough, frequently showing blood in the sputum, which indicates necrosis (tissue death) in the lung. About a third of these patients experience weight loss.

Symptoms of Atypical Pneumonia

General Symptoms for Atypical Pneumonias. Atypical nonbacterial pneumonia is most commonly caused by Mycoplasma and usually appears in children and young adults.

Symptoms progress gradually, often beginning with general flu-like symptoms, such as fatigue, fever, weakness, headache, nasal discharge, sore throat, ear ache, and stomach and intestinal distress.
Vague pain under and around the breast bone may occur, but the severe chest pain associated with typical bacterial pneumonia is uncommon.
Patients may experience a severe hacking cough, but it usually does not produce sputum.

Symptoms of Legionnaire's Disease. Symptoms of Legionnaire's disease usually evolve more rapidly and include high fever, a dry cough, and shortness of breath, often accompanied by headache, muscle pains, fatigue, gastrointestinal problems, and mental confusion.

HOW SERIOUS IS PNEUMONIA?

General Outlook

About 1.2 million people are hospitalized each year for pneumonia, which is the third most frequent reason for hospitalizations (births are first and heart disease is second). Although the majority of pneumonias respond well to treatment, the infection can still be a very serious problem. Together with influenza, pneumonia is the sixth leading cause of death in the US and is the leading cause of death from infection. Outlook for High-Risk Individuals

Severity varies widely depending on individual factors, including the following:

Hospitalized Patients. For patients who require hospitalization for pneumonia, the mortality rate is between 10% and 25%. If pneumonia develops in patients already hospitalized for other conditions, the mortality rates are higher. They range from 50% to 70% and are greater in women than in men.
Older Adults. The elderly have lower survival rates, particularly those with other medical problems. (Even when older individuals recover from community-acquired pneumonia, they have higher than normal mortality rates over the next several years.)
Very Young Children. About 20% of stillborn and very early infant mortality deaths are due to pneumonia. Small children who develop pneumonia are at risk for developing lung problems in adulthood.
Pregnant Women. Pneumonia poses a special hazard for pregnant women.
Patients with Impaired Immune Systems. Pneumonia is particularly serious in people with impaired immune systems, particularly AIDS patients, in whom pneumonia causes about half of all deaths.
Patients with Serious Medical Conditions. The disease is also very dangerous in people with diabetes, cirrhosis, sickle cell anemia, multiple myeloma, and in those who have had their spleens removed.

Risk by Organisms

Lower-Risk Organisms. The following organisms usually cause pneumonias that are responsive to treatment or mild.

S. Pneumonia is the most common organism and, although it can cause severe pneumonia, it is very responsive to many antibiotics.
Mycoplasma and Chlamydia are common causes of pneumonia in children and young adults. They are generally mild and rarely require hospitalization when they are appropriately treated, although recovery may still be prolonged. Severe and life-threatening cases are more likely to occur in elderly people with other medication conditions.

High-Risk Organisms. The following are high-risk infecting organisms that pose a particular risk for dangerous pneumonia:

High-risk gram positive bacteria. Staphylococcus aureus. Poses a higher risk for multiple small abscesses in the lung and necrosis (tissue death).

High-risk gram-negative bacteria include the following:

Pseudomonas aeruginosa.
Klebsiella pneumonia. Poses a risk for abscesses and severe lung tissue damage.
Legionella pneumophila . Particularly virulent and can cause damage throughout the body.

Viral pneumonia is usually very mild but there are exceptions.

Influenza pneumonia can be very serious.
Respiratory syncytial virus (RSV) pneumonia rarely poses a danger for healthy young adults. However, between 22,000 and 44,500 children are hospitalized each year because of pneumonia from RSV and the incidence seems to be increasing. Between 2% to 9% of hospitalized pneumonia cases in the elderly may be due to respiratory syncytial virus.

Complications of Pneumonia

Abscesses. Abscesses in the lung are thick-walled, pus-filled cavities that are formed when infection has destroyed lung tissue. They are frequently a result of aspiration pneumonia, when a mixture of organisms is carried into the lung. Abscesses can cause hemorrhage in the lung if untreated, but antibiotics that target specific anaerobic bacteria and other organisms have significantly reduced their danger. Abscesses are more common with Staphylococcus aureus or Klebsiella pneumoniae , and uncommon with Streptococcus pneumoniae .

Respiratory Failure. Respiratory failure is one of the most important causes of death in patients with pneumococcal pneumonia. Acute respiratory distress syndrome (ARDS) is the specific condition that occurs when the lungs are unable to function and oxygen is so severely reduced that the patient's life is at risk. Failure can occur from mechanical changes in the lungs caused by the pneumonia (called ventilatory failure) or from loss of oxygen in the arteries when pneumonia results in abnormal blood flow (called hypoxemic respiratory failure).

Bacteremia. Bacteremia (bacteria in the blood) is the most common complication of Streptococcus pneumoniae , but rarely does this infection spread to other sites. Bacteremia is also a frequent complication of other gram-negative organisms, including Haemophilus influenzae .

Pleural Effusions and Empyema. The pleura are two thin membranes:

The visceral pleura covers the lungs.
The parietal pleura covers the chest wall.

The narrow zone between these two pleural membranes normally contains a tiny amount of fluid that helps lubricate the lung. In about 20% of patients who are hospitalized for pneumonia, this fluid builds up around the lung.

In most cases, particularly in Streptococcus pneumoniae , the fluid remains sterile, but occasionally it can become infected and even filled with pus (a condition called empyema). Empyema sometimes occurs with Staphylococcus aureus or Klebsiella pneumoniae . The condition can cause permanent scarring. Pneumonia may also cause the pleura to become inflamed, which can result in breathlessness and acute pain.

Collapsed Lung. Air may fill up the area between the pleural membranes causing pneumothorax, or collapsed lung. The condition can be a complication of pneumonia (particularly pneumococcal pneumonia) or of some of the invasive procedures used to treat pleural effusion.

Other Complications of Pneumonia. In rare cases, infection may spread from the lungs to the heart and can even spread throughout the body, sometimes causing abscesses in the brain and other organs. Severe hemoptysis (coughing up blood) is another potentially serious complication of pneumonia, particularly in patients with other lung problems such as cystic fibrosis.

Long Term Effects of Atypical Pneumonias

Both Mycoplasma and Chlamydia pneumonias, the primary atypical pneumonias, are usually mild. Some research is suggesting, however, that they may have certain adverse long-term effects even in healthy younger individuals.

Heart Disease and Stroke. Research has suggested that the Chlamydia (C.) pneumoniae may trigger an immune response that causes inflammation and damage over time in the arteries or heart muscle. In a 2000 study, C. pneumoniae was associated with a thickening in the carotid artery which leads to the brain. Nevertheless, studies on a causal relationship between C. pneumonia and heart disease or stroke have been mixed. The most recent ones have found no strong association between the infection and heart disease while others downstate a possible link.

Neurologic Diseases. Some research suggests that C. pneumonia may affect the brain.

Researchers have also detected C. pneumoniae in areas of the brain affected by Alzheimer's but not in other areas, suggesting that the inflammatory response may contribute to this dreaded disease.
Another study reported an association between Chlamydia and multiple sclerosis, another neurologic disease caused by the inflammatory process.

Asthma. Chlamydia pneumoniae, Mycoplasma pneumoniae, and the respiratory syncytial virus are becoming important suspects in many cases of severe adult asthma. (Serious respiratory infections that occur in early childhood, however, probably do not play a role in asthma that develops in adulthood.)

WHO GETS PNEUMONIA?

General Risk Factors for Community-Acquired Pneumonia

Community-acquired pneumonia is the most common type and develops outside of the hospital. Each year between two and four million people in the US develop community-acquired pneumonia, and 600,000 people are hospitalized because of it. The elderly (who have diminished cough and gag reflexes and faltering immune systems), infants, and young children (who have immature immune systems and narrow airways) are at greater risk for pneumonia than are young and middle-aged adults. In the US the incidence is higher in African-Americans than in Caucasians.

General Risk Factors for Hospital-Acquired (Nosocomial) Pneumonia

Aside from specific conditions that predispose one to pneumonia, people who are hospitalized have a higher risk for pneumonia than those who are not. Pneumonia that is contracted in the hospital is called nosocomial pneumonia and affects an estimated five to 10 out of every 1000 hospitalized patients every year. The following conditions put hospitalized people at higher risk:

Surgery, particularly splenectomy or operations that impair coughing.
Being in the intensive care unit on mechanical ventilators. Ventilated patients who lie flat on their backs are at particular risk for aspiration pneumonia; raising the patient up may reduce this risk.
Hospitalized patients are particularly vulnerable to gram-negative bacteria and staphylococci, which can be very dangerous, particularly in people who are already ill

Risk Factors in Adults

Dormitory or Barrack Conditions. Recruits on military bases and college students are at higher than average risk for Mycoplasma pneumonia , which is usually mild. These groups are at lower risk, however, for more serious types of pneumonia.

Smoke and Environmental Pollutants. The risk for pneumonia in smokers of more than a pack a day is three times that of nonsmokers. Those who are chronically exposed to cigarette smoke, which can injure airways and damage the cilia, are also at risk. Quitting smoking reduces the risk of dying from pneumonia to normal, but the full benefit takes ten years to be realized. Toxic fumes, industrial smoke, and other air pollutants may also damage cilia function.

Drugs and Alcohol. Alcohol or drug abuse is strongly associated with pneumonia. These substances act as sedatives and can diminish the reflexes that trigger coughing and sneezing. Alcohol also interferes with the actions of macrophages, the white blood cells that destroy bacteria and other microbes. Intravenous drug abusers are at risk for pneumonia from infections that originate at the injection site and spread through the blood stream.

Compromised Immune Systems

People with impaired immune systems are extremely susceptible to pneumonia. In addition to AIDS, other conditions that compromise the immune system include organ transplantation, chemotherapy, and cancers, especially leukemia and Hodgkin's disease. Patients who are on corticosteroid or other medications that suppress the immune system are also prone to infection.

Chronic Lung Disease

Chronic obstructive lung diseases, including chronic bronchitis and emphysema, are major risk factors for pneumonia.

Specific Risk Factors for Recurrent Pneumonia in Children

Certain children have a higher than normal risk for pneumonia and its recurrence. Conditions that predispose infants and small children to pneumonia include the following:

Impaired immune system.
Gastroesophageal reflux disorder.
Inborn lung or heart defects.
Abnormalities in muscle coordination in the mouth and throat.
Asthma.

Certain genetic disorders. They include sickle-cell disease, cystic fibrosis (which causes mucus abnormalities), and Kartagener's syndrome (which results in malfunctioning cilia, the hair-like cells lining the airways).

HOW IS PNEUMONIA DIAGNOSED?

In many cases of mild-to-moderate community-acquired pneumonia, the physician is able to diagnose and treat pneumonia based solely on a history and physical examination. Often, however, a diagnosis is not straightforward, particularly in hospitalized patients.

Medical and Personal History

The patient's history is an important part of the diagnosis of pneumonia. The patient should be sure to report any of the following:

recent or chronic respiratory infection,
exposure to people with pneumonia or other respiratory illnesses (such as tuberculosis),
history of smoking,
alcohol or drug abuse,
recent travel, and
occupational risks.

Physical Examination

Use of the Stethoscope. The most important diagnostic tool for pneumonia is the stethoscope. Sounds in the chest that may indicate pneumonia are the following:

Rales (a bubbling or crackling sound). Rales on one side of the chest and rales heard while the patient is lying down is strongly suggestive of pneumonia.
Rhonchi (abnormal rumblings indicating the presence of thick fluid).

Percussion. The physician will also use a test called percussion, in which he or she taps the chest lightly. A dull thud instead of a healthy hollow-drum-like sound, indicates certain condition that suggest pneumonia, including the following:

Consolidation (a condition, in which the lung becomes firm and inelastic).
Pleural effusion (fluid build-up in the space between the lungs and the lining around it).

Diagnostic Difficulties in Hospitalized Patients

Diagnosing pneumonia is particularly difficult in hospitalized patients (called nosocomial pneumonia) for a number of reasons, including the following:

Many hospitalized patients have similar symptoms, including fever or signs of lung infiltration on x-rays.
In hospitalized patients, sputum or blood tests often indicate the presence of bacteria or other organisms, but such agents do not necessarily indicate pneumonia.

For a diagnosis of nosocomial pneumonia, physicians should be sure to rule out other conditions, using a chest x-ray, two sets of blood cultures, a urine analysis for Legionella, lung fluid sample, and possibly other tests for specific organisms.

Laboratory Tests for Diagnosing Infection and Identifying Bacterial Agents

Although antibiotics are available that can destroy a wide spectrum of organisms, it would be preferable to use an antibiotic that can target the specific microorganism causing the pneumonia. Researchers, then, are looking for laboratory tests that would identify the specific organism or virus causing the pneumonia. Unfortunately, people harbor many bacteria, and sputum and blood tests are not always effective in distinguishing between harmless and harmful microscopic agents. In severe cases, physicians particularly need to use invasive diagnostic measures to identify the infecting agent.

Urine Tests. A urine test (NOW) is up to 93% accurate in identifying S. pneumoniae within 15 minutes. However, a 2000 study indicated that it is not likely to be useful in diagnosing S. pneumoniae as a cause of pneumonia in children, since the organism is very common in the noses and throats of children. This organism, then, would very likely be picked up by the test even if it were not the cause of the pneumonia.

Sputum Tests. Only a sample of sputum coughed from the lungs will yield the infecting organism, and, even then, tests are not always successful in revealing the culprit. The following steps may be required:

The physician first asks the patient to cough as deeply as possible to produce an adequate sputum sample. A shallow cough produces a sample that usually only contains normal mouth bacteria.
A patient who is not able to cough sufficiently may be asked to inhale a saline spray that helps produce an adequate sputum sample.
In some cases, a tube will be inserted through the nose down into the lower respiratory tract to induce a deeper cough.

Even before sending the sample to the laboratory, the physician will check it for the following:

Presence of blood (an indication of infection).
Color and consistency. If the sputum is opaque and colored yellow, green, or brown, then infection is likely. Clear, white, glistening sputum indicates no infection.

In the laboratory, the sputum sample may be used as follows:

A Gram's stain is made, which may reveal the presence of bacteria and whether they are gram-negative or positive.
A sputum culture may be performed, in which organisms are grown in the laboratory.

Blood Tests. Blood tests may be used for the following:

White blood cell count. High levels indicate infection.
Blood cultures. They may be performed for detecting the specific organism causing the pneumonia, but are not often helpful in distinguishing harmful from harmless organisms. They are accurate in only 10% to 30% of cases, and their use should generally be limited to severe cases.
Detection of antibodies to S. pneumoniae. Researchers are using specialized techniques to detect antibodies to S. pneumoniae (immune factors that target specific foreign invaders), but it is not clear if they are accurate.

Laboratory Tests for Less Common Organisms

If uncommon organisms, such as Legionella, Mycoplasma, and Chlamydia organisms, are strongly suspected more advanced laboratory tests may be used:

Specialized techniques can detect antibodies to the organisms in blood samples, but these antibodies, such as those responding to Mycoplasma or Chlamydia , are not present early enough in the course of pneumonia to permit prompt diagnosis and treatment.
A test performed on whole blood samples that uses a technique called polymerase chain reaction (PCR) is useful for identifying certain atypical strains, including Mycoplasma and Chlamydia pneumoniae, but it is expensive.
A urine test can be used to diagnose some cases of Legionnaire's disease.
DNA probes are being developed to detect these organisms in respiratory secretions.

In addition, special stains and cultures are required to detect tuberculosis and fungal infections.

Chest X-Rays and Other Imaging Techniques

X-Rays. A chest x-ray is nearly always taken to confirm a diagnosis of pneumonia. It may reveal the following:

White areas in the lung called infiltrates, which indicate infection.
Complications of pneumonia, including pleural effusions (fluid around the lungs) and abscesses.

Other Imaging Tests. Computed tomography (CT) scans or MRIs may be obtained in the following circumstances:

If x-ray results are unclear.
When patients do not respond to antibiotics.
When patients have complications.
When patients have other serious health problems.

These more sophisticated imaging techniques can help detect the presence of tissue damage, abscesses, and enlarged lymph nodes. They can also detect some tumors that block bronchial tubes. No imaging technique can determine the actual organism causing the infection.

Invasive Diagnostic Procedures

Invasive diagnostic procedures may be required in the following circumstances:

When patients have life-threatening complications.
When patients have failed standard treatments for no known reason.
When AIDS or other immune problems are present.

Each of the procedures has potential complications and is not used under ordinary conditions.

Thoracentesis. If a physician detects pleural effusion and suspects that empyema (pus) is present, thoracentesis is performed:

Fluid in the pleura is withdrawn using a long thin needle inserted between the ribs.
The fluid is then tested using blood cell counts, Gram stains, cultures, and chemical tests.

Complications of this procedure include collapsed lung, bleeding, and introduction of infection.

Bronchoscopy. A bronchoscopy employs the following:

The patient is given a local anesthetic, supplementary oxygen, and sedatives.
The physician inserts a fiberoptic tube into the lower respiratory tract through the nose or mouth.
The tube acts like a telescope into the body, allowing the physician to view the wind-pipe and major airways for pus, abnormal mucus, or other problems.
The doctor removes specimens for analysis and can also treat the patient by removing any foreign bodies or infected tissue encountered during the process.
Bronchoalveolar lavage (BAL) may be employed. This involves injecting high amounts of saline through the bronchoscope into the lung and then immediately suctioning the fluid back, which is then analyzed in the laboratory. Studies find BAL to be an effective method for detecting specific infection-causing organisms in patients with serious pneumonia.

The procedure is usually very safe, but complications can occur. They include allergic reactions to the sedatives or anesthetics, asthma attacks in susceptible patients, and bleeding. Fever may follow the procedure.

Lung Biopsy. In very severe cases of pneumonia or when the diagnosis is unclear in specific cases, particularly in patients with damaged immune systems, a lung biopsy may be required. Biopsies can be performed in one of two ways:

A Lung Tap. This procedure typically uses a needle inserted between the ribs to draw fluid out of the lung for analysis. It is known by a number of names including lung aspiration, lung puncture, thoracic puncture, transthoracic needle aspiration, percutaneous needle aspiration, and needle aspiration. It is a very old procedure that is not done often any more, particularly in children, since it is invasive and poses a slight risk for collapsed lung. Some experts argue, however, that a lung tap offers a more accurate solution than other methods for identifying bacteria and the risk it poses is slight. Given the increase in resistant bacteria, they believe its use should be reappraised in young people.
Surgically (thoracotomy), using general anesthesia and an incision. This is used for diagnosis only in very severe cases. As with bronchoscopy, the procedure can also be used to treat the patient, removing damaging lung tissue and, in severe cases, removing the entire lobe (lobectomy). (In such cases, remaining lung tissue re-expands after surgery to compensate for any removed tissue.)

Ruling out Other Disorders that Affect the Lung

Common Causes of Persistent Coughing. Over 30 million people seek medical help each year for persistent coughing, which is nearly always temporary and harmless when other symptoms, such as fever, are not present. Roughly, the first four most common causes of persistent coughing are asthma, postnasal drip, gastroesophageal reflux disease, and chronic bronchitis. Other obvious common causes of chronic cough include heavy smoking or the use of drugs known as ACE inhibitors.

Acute Bronchitis. Acute bronchitis is an infection in the passages that carry air from the throat to the lung causing a cough that produces phlegm. It is almost always caused by a virus and usually resolves on its own within a few days. (In some cases, acute bronchitis caused by a cold can last for several weeks, and some physicians believe that a cough should not be considered to be chronic until it persists for eight weeks.) [ See Box What Is Acute Bronchitis?]

Chronic Bronchitis. Chronic bronchitis causes shortness of breath and is often accompanied by infection, mucus production, and coughing, but it is a long-term and irreversible condition. The same microbes cause chronic bronchitis and pneumonia, and symptoms of the two disorders are often similar. They include fatigue, coughing, fever, and production of sputum.

Patients with bronchitis are less likely, however, to have shortness of breath, chills, very high fevers, and other signs of severe illness.
Those with pneumonia usually cough up heavy sputum, which is also more likely to contain blood.
Patients with bronchitis are more prone to wheezing than are those with pneumonia.
X-rays of patients with bronchitis are unlikely to show fluid or consolidation in the lung.

Asthma. In asthma, the cough is accompanied by wheezing and occurs mostly at night or during activity. Fever is rarely present (unless the patient also has an infection). Asthmatic symptoms from occupational causes can cause persistent coughing, which is usually worse during the work week. Tests called the methacholine inhalation challenge and pulmonary function studies may be effective in diagnosing asthma.

Ruling out Causes in Children. Important causes of coughing in children at different ages include:

Asthma.
Physical abnormalities in infants under 18 months.
Sinusitis in children 18 months to six years.
Psychologic causes in older children and adolescents.

Other Disorders that Affect the Lung. Many conditions mimic pneumonia, particularly in hospitalized patients. Some include the following:

Tuberculosis.
Bronchial asthma.
Bronchiectasis (irreversible widening of the airways, usually associated with birth defects, chronic sinus or bronchial infection, or blockage).
Atelectasis (collapse of lung tissue).
Congestive heart failure. (If heart failure affects the lungs, fluid-build up can occur and cause persistent cough, shortness of breath, and wheezing. In such cases, symptoms are usually worse at night.)
Severe allergic reactions, such as to drugs.
Adult respiratory distress syndrome (ARDS).
Lung cancer.
Interstitial pulmonary fibrosis (a non-infectious inflammation of the is marked by progressive damage and scarring). It can occur from a number of conditions, including chemicals, injury, autoimmune disease, and cancer. The cause is often unknown.

WHAT IS ACUTE BRONCHITIS?

Acute bronchitis is an infection in the passages that carry air from the throat to the lung causing a cough that produces phlegm. In such cases, the airway tubes are inflamed and collect mucus. In 95% of cases, acute bronchitis is caused by a virus and is spread from person to person through coughing. In some cases other tiny microbes called Mycoplasma or Chlamydia may be responsible.

Symptoms of Acute Bronchitis

The cough in acute bronchitis usually lasts for about a week to ten days but in about half of patients coughing can last for up to three weeks and 25% of patients continue to cough for over month.

Complications of Acute Bronchitis

Acute bronchitis is nearly always temporary. Sometimes it can last for weeks to months if the airways are not healing properly. Pneumonia may be present if coughing is continuous and hacking, if blood appears in the sputum, and if the patient has a high fever and signs of severe illness, such as shortness of breath or extreme weakness and fatigue. [For more information see the Report Colds, Flu, Sore Throat, and Acute Bronchitis. ]

Of particular interest and some concern are the roles of Mycoplasma and Chlamydia, two of the infectious organisms that cause acute bronchitis. These agents are being investigated for their roles as possible causes of asthma. Chlamydia is also being investigated as a trigger for processes leading to coronary artery disease.

Treatments for Persistent Acute Bronchitis

A number of cough remedies are available for coughing due to a cold that is not persistent. [See What Are the Treatments for Symptoms of Colds and Mild Flus?] If acute bronchitis develop, however, other treatments may be necessary.

Bronchodilators. For some patients with acute bronchitis, inhaled medications called bronchodilators may be effective. These drugs relax and open the airways and so may relieve symptoms and reduce the duration of the coughing. The most common bronchodilator used for acute bronchitis is albuterol (Proventil, Ventolin), called salbutamol outside the US, which is known as a short-acting beta2-agonist. Others are also available.

Antibiotics. Acute bronchitis associated with colds is almost always caused by viruses and almost never warrants antibiotics. Exceptions possibly include pertussis (whooping cough) or coughing that lasts longer than 10 days in children with chronic lung disease (but not asthma). Some physicians believe that antibiotics may prevent bacterial infections from developing in the lungs of patients with acute bronchitis, although several studies have reported few or no benefits from antibiotics for uncomplicated bronchitis in either children or adults. Needless to say, antibiotics are warranted if the coughing is caused by pneumonia.

WHAT ARE THE GENERAL GUIDELINES FOR TREATING PNEUMONIA?

Up to 10% of all adult hospitalizations in the US are due to pneumonia. Studies are indicating that many patients are hospitalized unnecessarily for pneumonia and those that are could be released sooner. One study, for example, estimated that one-third of patients who are now routinely hospitalized for pneumonia could be treated safely at home, and another 20% could be released from the hospital with only a short period of observation. A number of strategies are being devised to determine when and which patients can be safely discharged.

Categorizing Severity

One approach for determining whether a patient should be hospitalized categorizes patients into five classes depending on risk factors for severity, with class 1 being the least severe (having less than 0.5% risk for mortality) and class 1 being the most severe (having at least a 10% mortality risk).

Ruling out the Least Severe Cases. The procedure for deciding on hospitalization or not starts by ruling out patients in the lowest risk groups (class 1 and 2), who can be discharged with outpatient care only. This can often be done with a simple physical examination, which can often rule out a severe condition. Patients in low-risk categories have the following characteristics:

Under age 50 and not a patient in a nursing home.
No other major illnesses are present.
No serious symptoms are present (eg, altered mental state, rapid pulse or breathing rate, very low blood pressure, very high fever).

Even these criteria, however, should not be carved in stone. Physicians still must use their own judgment and take mitigating factors into consideration.

As examples, the following young people with signs of pneumonia should be hospitalized, even if they fit class 1 categories:

Any infant under a month.
Young adults with alcoholism or severe psychiatric conditions.
Young adults or children with abnormal heart rhythms.
Young adults or children who are vomiting heavily.
Children who are dehydrated.

Determining The Next Levels of Severity. If a patient cannot be categorized in class I, the next step is to determine which of the other four higher classes the patient fits. This step involves assigning points to other findings, including the following:

Laboratory test results.
X-ray findings.
Demographics (ie, male or female, nursing home patient).

The points are added and the patients are scored:

Patients who score low points on these findings are assigned class II and III; they can usually be treated at home or need only to be hospitalized for 24 hours for observation.
Patients with higher scores are placed in classes IV and V and are hospitalized.

It should be noted that home care may be possible even in severe cases, when there is good support and available home nursing services. Often, caregivers can even be trained to administer intravenous antibiotics and chest therapy to patients at home.

Home Treatment

Most patients with mild pneumonia can be treated at home with oral antibiotics. The following are also suggested:

Patients should be sure to drink plenty of liquids.
Coughing should not be suppressed, since this is an important reflex for clearing the lungs. Some physicians advise taking expectorants, such as guaifenesin (Breonesin, Glycotuss, Glytuss, Hytuss, Naldecon Senior EX, Robitussin), to loosen sputum. There is no proof that any of these products make much difference in outcome.
Mild pain can be treated with aspirin (adults only), acetaminophen (Tylenol and other brands), or ibuprofen (Advil, Motrin, Rufen).
For severe pain, codeine or other stronger pain relievers may be prescribed. It should be noted, however, that codeine and other narcotics suppress coughing, so they should be used with care in pneumonia and often require monitoring.
Of some interest is a laboratory study reporting that aromatic oils containing oregano, thyme, and rosewood destroyed S. pneumoniae . It is not known whether they have any effect on pneumonia in people, but they are harmless and pleasant in any case.
Patients should practice chest therapy. [ See Box Chest Therapy.]

Hospitalization Guidelines

Treatment. If the pneumonia is severe enough for hospitalization, the standard treatment is intravenous administration of antibiotics for five to eight days. (In cases of uncomplicated pneumonia, many patients may require only two or three days of intravenous antibiotics followed by oral therapy.) Oral antibiotics are prescribed when the patient has improved substantially or leaves the hospital.

Duration of Stay. In the past, patients remained in the hospital eight to 11 days, but hospital stays are shorter now in most cases. It is important to stress, however, that once patients have been hospitalized, they should remain there until all their vital signs are stable. Most patients become stabilized in three days.

Many experts use seven variables to measure such stability and to determine if the patient can go home:

Temperature. (Opinions differ on temperature goal. Some experts believe that a patient can go home if the temperature levels drop to 101 degrees F. Stricter criteria would require that it be at or close to normal.)
Respiration rate. (Goal is a normal breathing rate, although expert opinion differs on the degree of normality required to be discharged.)
Heart rate. (Goal is 100 beats per minute or less.)
Blood pressure. (Goal is systolic blood pressure of 90 mmHg or greater.)
Oxygenation. (Goal of oxygen levels in the blood determined by the physician.)
The ability to eat. (Goal is regular appetite.)
Mental function. (Goal is normal.)

Patients or their families should discuss these criteria with the physician. One 1998 study indicated that once patients are stabilized only 1% deteriorate to the point that readmission is required.

Chest Therapy

Chest therapy using incentive spirometry, rhythmic inhalation and coughing, and chest tapping are all important techniques to loosen the mucus and move it up out of the lungs. It should be used both in the hospital and when the patient returns home during recovery.

Incentive Spirometry. The patient uses an incentive spirometer at regular intervals.

The spirometer is a hand-held clear plastic device that includes a breathing tube and a container with a movable gauge.
The patient first exhales through the tube.
Then the patient inhales as strongly as possible.
The force of the inhalation raises a gauge inside the device to the highest level possible.

This practice helps the patient exercise the lungs. The height of the gauge at inhalation also helps the health professional to determine the state of the patient's lung function.

Rhythmic Breathing and Coughing. During recovery, the patient performs rhythmic breathing and coughing every four hours:

Before starting the breathing exercise, the patient should tap lightly on the chest to loosen mucus within the lung. If available, a caregiver should also tap on the patient's back.
The patient inhales rhythmically and deeply three or four times.
The patient then coughs as deeply as possible with the goal of producing sputum.

WHAT ANTIBIOTICS ARE USED FOR PNEUMONIA?

General Guidelines for Determining Specific Antibiotic Choices

Dozens of antibiotics are available that can treat most cases of pneumonia in or out of the hospital, but it is sometimes difficult for the physician to select the best drug. [ See Box Antibiotic Classes.] Often the infecting organism remains unknown even after testing. In determining the appropriate antibiotic, the physician must first answer a number of questions:

How severe is the pneumonia? Mild-to-moderate cases can be treated at home with oral antibiotics while severe pneumonia usually requires intravenous antibiotics administered in the hospital.
If the organism causing the pneumonia is not known, was the disorder community-acquired pneumonia (CAP) or hospital-acquired (also called nosocomial)? Different organisms are usually involved in each setting, and the physician can often use this information to guess the most likely organism causing the pneumonia.
If the organism is known, is it typical or atypical? Typical bacterial, community acquired pneumonias for example, are usually caused by Streptococcus pneumoniae , Haemophilus influenzae , or Moraxella catarrhalis , which have traditionally been treated with penicillin or other standard antibiotics. Such antibiotics, however, do not affect atypical organisms, such as Legionella, Mycoplasma, or Chlamydia.

Once an antibiotic has been chosen, there are still difficulties:

Individuals respond differently to the same antibiotic depending on age, health, size, and other factors.
Patients can be allergic to certain antibiotics, thus requiring alternatives.
Patients may harbor strains of bacteria that are resistant to certain antibiotics. [ See Box Warnings on Antibiotic Over-Use and Resistant Bacteria.]

Antibiotic Treatments for Atypical Pneumonia

An oral macrolide, either erythromycin, clarithromycin, or azithromycin, is the first choice for children or young people with mild to moderate atypical pneumonia caused by Mycoplasma or Chlamydia, without other medical problems.
Newer quinolones may also be options.
Azithromycin or a newer quinolone may be a good choice for Legionella and severe atypical pneumonias.

Antibiotic Treatments for Bacterial Community-Acquired Pneumonia

Bacterial community-acquired pneumonia (CAP) is usually caused by the gram-positive bacteria Streptococcus pneumoniae . Other CAP organisms include Streptococcus pyogenes, Staphylococcus aureus, or Moraxella catarrhalis .

Treating CAP Patients at Home. Guidelines published by the Infectious Diseases Society of America recommend that either macrolides or newer fluoroquinolones be used for the treatment of CAP in the nonhospital setting. Some examples of studies on specific agents include the following:

Macrolides. One study found that children with acute pneumonia and bronchitis did as well on a three-day course of the new macrolide zithromycin (Zithromax) as those on 10-day older erythromycin.
Quninolones. The quinolone levofloxacin (Levaquin), is the first drug approved specifically for penicillin-resistant Streptococcus pneumoniae . Gatifloxacin (Tequin) and moxifloxacin (Avelox), other new quinolones, also need to be taken once a day.

Treating CAP Patients in the Hospital or for More Severe Cases.

For severe CAP, experts recommend extended-spectrum penicillins, such as piperacillin/tazobactam (Zosyn) with or without an aminoglycoside (such as tobramycin), which are also effective against dangerous gram-negative bacteria.

Third-generation cephalosporins (eg, ceftriaxone or cefotaxime) have been used for mild-to-moderate cases in hospitalized patients (administered intravenously). Such drugs target a wide range of bacteria although they are not effective against atypical organisms such as Legionella or Chlamydia, which may be a hazard for patients being treated in the intensive care unit for severe CAP.

Most physicians add a macrolide or a newer fluoroquinolone to the cephalosporin regimen for CAP patients who need to be hospitalized.

Antibiotic Treatments for Hospital-Acquired Gram-Negative Pneumonia

Patients with hospital-acquired pneumonia are at high risk for infection from gram-negative organisms. Such organisms include Pseudomonas aeruginosa and Klebsiella pneumonia, which require aggressive specific therapy.

Powerful antibiotics used against these organisms include the fourth-generation cephalosporin cefepime or carbapenems, such as meropenem.
Multidrug therapy may be necessary, particularly for patients who are on mechanical ventilators and therefore at very high risk for multiple dangerous organisms.

Preventing and Treating Respiratory Syncytial Virus (RSV) Pneumonia in Children

Prevention of RSV. Two agents have been approved for protecting high-risk infants against RSV pneumonia:

Palivizumab (Synagis) is known as a monoclonal antibody, a genetically engineered antibody, which targets the RSV virus.
RSV immune globulin (RespiGam) is made up of antibodies to RSV that are obtained from the blood of healthy infants.

RespiGam must be administered intravenously while Synagis can be injected.

Treatment of RSV. Ribavirin is the first treatment approved for respiratory syncytial virus pneumonia, although it has only modest benefits. The American Academy of Pediatrics recommends it for children at high risk for serious complications of RSV. In one study, a combination of ribavirin with RSV immune globulin was more effective than either drug alone.

Drugs that open the airways of the lungs, known as bronchodilators, are sometimes used to treat RSV infection, but evidence on their benefits is conflicting. One study of albuterol, a common bronchodilator, however, indicated that epinephrine may be more effective.

Side Effects of Antibiotics

Most antibiotics have the following side effects (although specific antibiotics may have other side effects or fewer of the standard ones).

The most common side effect for nearly all antibiotics is gastrointestinal distress.
Antibiotics double the risk for vaginal infections in women. Taking supplements of acidophilus or eating yogurt with active cultures may help restore healthy bacteria that offset the risk for such infections.
Allergic reactions can also occur with all antibiotics but are most common with medications derived from penicillin or sulfa. These reactions can range from mild skin rashes to rare but severe, even life-threatening anaphylactic shock.
Certain drugs, including some over-the-counter medications, interact with antibiotics; patients should inform the physician of all medications they are taking and of any drug allergies.

Antibiotic Classes

Beta-Lactams

The beta-lactam antibiotics share common chemical features and include penicillins, cephalosporins, and some newer similar agents. Their primary actions to interfere with bacterial cell walls.

Penicillins. Amoxicillin (Amoxil, Polymox, Trimox, Wymox, or any generic formulation) is probably the most common penicillin. It is both inexpensive and at one time was highly effective against the S. pneumoniae bacteria. Unfortunately, bacterial resistance to amoxicillin has increased significantly, both among S. pneumoniae and H. influenzae .

Amoxicillin-clavulanate (Augmentin) is known as an augmented penicillin, which works against a wide spectrum of bacteria. Ampicillin, also a form of penicillin, is an equally inexpensive alternative to amoxicillin but requires more doses and has more severe gastrointestinal side effects than amoxicillin.

Cephalosporins. These agents have also become less effective against S. pneumoniae . They are often classed in the following:

First generation includes cephalexin (Keflex), cefadroxil (Duricef, Ultracef), and cefaclor (Ceclor). These agents may be useful for gram-positive organisms, except resistant S. pneumoniae .
Second and third generation include cefuroxime (Ceftin), cefpodoxime (Vantin), loracarbef (Lorabid), cefditoren (Sprectracef), cefixime (Suprax), and ceftibuten (Cedex). These are effective against a wide range of gram-negative bacteria. Most are not very effective against Staphylococcus or S. pneumoniae bacteria that have developed resistance to penicillin.

Newer Beta-Lactam Agents.

Carbapenems include meropenem (Merrem), and combinations (imipenem/cilastatin [Primaxin]). These agents cover a wide spectrum of bacteria. They are now used for serious hospital-acquired infection and for bacteria that have become resistant to other beta-lactam drugs. Imipenem has serious side effects used alone so it is given in combinations with another agent, cilastatin, to offset these adverse effects.

Fluoroquinolones (Quinolones)

Fluoroquinolones (also simply called quinolones) interfere with the bacteria's genetic material so they cannot reproduce.

Ciprofloxacin (Cipro), a second-generation quinolone, remains the most potent quinolone against Pseudomonas aeruginosa bacteria but is not very effective for gram-positive bacteria.
Newer third-generation quinolones are currently the most effective agents against a wide range of common bacteria. They include levofloxacin (Levaquin), sparfloxacin (Zagam), gemifloxacin (Factive), and gatifloxacin (Tequin). Levofloxacin is the first drug approved specifically for penicillin-resistant S. pneumoniae . Some of the newer fluoroquinolones also only need to be taken once a day, which makes compliance easier. A few of the third-generation quinolones cause photosensitivity (eg, sparfloxacin).
A fourth generation includes moxifloxacin (Avelox), trovafloxacin, and clinafloxacin. Studies on moxifloxacin are indicating that it is safe and effective against many gram-negative and gram-positive bacteria.

Macrolides and Azalides

Macrolides and azalides are antibiotics that also effect the genetics of bacteria. They include erythromycin, azithromycin (Zithromax), clarithromycin (Biaxin), and roxithromycin (Rulid). These antibiotics are effective against S. pneumoniae and M catarrhalis , but there is increasing bacterial resistance to these agents. Except for erythromycin they are effective against H. influenzae . A new once-a-day formulation (Biaxin XL) is now available

Tetracyclines

Tetracyclines inhibit bacterial growth. They include doxycycline, tetracycline, and minocycline. They can be effective against S. pneumoniae and M. catarrhalis , but bacteria that are resistant to penicillin are also often resistant to doxycycline. Tetracyclines have unique side effects among antibiotics, including skin reactions to sunlight, possible burning in the throat, and tooth discoloration.

Trimethoprim-Sulfamethoxazole

Trimethoprim-sulfamethoxazole (Bactrim, Cotrim, Septra) is less expensive than amoxicillin and particularly useful for adults with mild bacterial upper respiratory infections who are allergic to penicillin. It is no longer effective, however against certain streptococcal strains. It should not be used in patients whose infections occurred after dental work or in patients allergic to sulfa drugs. Allergic reactions can be very serious.

Aminoglycosides

Aminoglycosides are given by injection for very serious bacterial infections. (gentamicin, kanamycin, tobramycin, amikacin). Some are available in inhaled forms or by irrigation (applying a solution directly to mucous membranes, skin, or body cavity). They can have very serious side effects, including damage to hearing, sense of balance, and kidneys.

Lincosamide

Lincosamides prevent bacteria from reproducing. The most common lincosamide is clindamycin (Cleocin). This antibiotic is useful against many S. pneumoniae bacteria but not against H. influenzae.

Glycopeptide

Glycopeptides (vancomycin, teicoplanin) is used for Staphylococcus aureu s that have become resistant to standard antibiotics. It is available in intravenous and oral forms. Resistance to this drug is growing.

Ketolides

Telithromycin (Ketek) is the first antibiotic in the ketolide class. It is has been approved for treating community acquired pneumonia and is showing great promise in treating many of the otherwise antibiotic-resistant bacterial strains. Studies on long term-safety are still needed.

Oxazolidinone

Linezolid (Zyvox) is the first antibacterial drug in a new class of synthetic antibiotics called oxazolidinones. It has been proven effective against certain aerobic gram-positive bacteria, including Staphylococcus aureus (MRSA).

Streptogrammins

Quinupristin/dalfopristin [Syndercid].

Warnings on Antibiotic Over-Use and Resistant Bacteria

Of great concern is the emergence of common bacteria strains that are now resistant to many standard antibiotics. Among the bacteria are those that cause serious respiratory infections, including pneumonia. Although new powerful antibiotics continue to be designed, they are expensive and are also prone to resistance eventually.

Over-Use of Antibiotics. One of the primary causes of the increase in resistant bacteria is the world-wide overuse of antibiotics. Each year in the United States alone 160 million prescriptions are written for antibiotics equal to about 25,000 tons of these drugs. About half are used for patients and half animal, fish, and other agricultural uses.

Virtually no antibiotics for colds are necessary, even with persistent cough and thick, green mucus, unless there is evidence of an accompanying infection. In one disturbing study antibiotics were prescribed for nearly half of children who went to the doctor for a common cold. And experts estimate that, outside the hospital setting, only half of the antibiotics currently being prescribed for sore throat and 20% of prescriptions for persistent coughing are necessary.

Antibiotics may be required for upper respiratory tract infections only under certain situations, such as the following:

In patients, particularly small children or the elderly, who have medical conditions that put them at high risk for complications from such infections.
In strep throat (which is caused by the Streptococcal bacteria). (Strep throat makes up only about 12% of all sore throat cases.)
In some cases of an accompanying sinusitis, ear, or other bacterial infection. [See the Reports Ear Infections (Otitis Media) in Children and Sinusitis.]

High-Risk Areas. The prevalence of such antibiotic-resistant bacteria has dramatically increased worldwide. Studies in North, Central and South America, Asia, and southern Europe report that more than half of Streptococcus pneumoniae is resistant to many standard antibiotics. In general, regions and institutions with the highest rate of resistance are those in which antibiotics are heavily prescribed. In the US, the Pacific Northwest has a somewhat lower rate than other regions have.

At-Risk Patients. As of yet, the average person is not endangered by this problem. Patients at greater risk for developing an infection resistant to common antibiotics are those with following conditions:

Being very old or very young.
Being exposed to patients with drug-resistant infection.
Hospitalization in intensive care.
Having had an invasive procedure.
Having had a hospital stay.
Having had prior and prolonged antibiotic therapy, particularly within the past four to six weeks.
The presence of a wound.
Having intravenous lines, catheters, or tubes down the throat.
Being immunosuppressed.

Positive News. There are some signs of hope:

The Centers for Disease Control and Prevention (CDC) is reporting a decline in antibiotic prescriptions since the early 1990s.
And, countries that have reduced their dependence on penicillin are reporting a parallel decline in bacteria resistant to the antibiotic.
Innovative approaches are being investigated. One involves creating antibiotics that have the capacity to either self-destruct or regenerate themselves.
Greater emphasis is being placed on development of vaccines and expanding immunization programs to prevent infections in the first place.

What Patients and Parents Can Do.

For acute bronchitis caused by colds or mild flu, use remedies to relieve symptoms. Realize that antibiotics will not shorten the course of a viral infection.
Don't pressure a physicians into prescribing an antibiotic if it is clearly inappropriate. The physician very often will give in. It is important for patients and parents to understand that although antibiotics may bring a sense of security, they provide no significant benefit for a person with a viral infection, and overuse can contribute to the growing problem of resistant bacteria.
If an antibiotic is prescribed, take the full course unless advised by the physician to stop because of evidence that a bacteria is not present.

WHAT PROCEDURES ARE USED FOR PNEUMONIA?

Surgical Procedures

Although most patients with pneumonia do not require invasive therapy, patients with abscess, empyema, or certain other complications may require thoracentesis, bronchoscopy, and thoracotomy [ see How is Pneumonia Diagnosed?, above].

Chest Tubes

Chest tubes are needed if empyema is present in order to drain the infected pleural fluid, but they are not required for pneumonia or abscesses.

If needed, the tubes are inserted under local anesthetic and remain in place for two to four days.
Complications include infection, accidental injury of the lung, perforation of the diaphragm, and fluid build-up within the lung if the pleural fluid is removed too rapidly.
Removal of the tubes is done in one quick movement without anesthetic and can be very distressing, although some patients experience no discomfort.
Removing the chest tubes occasionally causes the lung to collapse requiring the reintroduction of a chest tube to inflate the lung.

HOW IS PNEUMONIA PREVENTED?

The best way to prevent serious respiratory infections, such as pneumonia, is to avoid and, if unavoidable, effectively treat colds and influenza. [For detailed information see the Well-Connected Report Upper Respiratory Tract Infections (Colds, Flu, Sore Throat, and Acute Bronchitis ).]

Lifestyle Habits for Preventing Colds

Good Hygiene. Everyone should always wash his or her hands before eating and after going outside. Ordinary soap is sufficient. Antibacterial soaps add little protection, particularly against viruses. In fact, one study suggests that common liquid dish washing soaps are up to 100 times more effective than antibacterial soaps in killing respiratory syncytial virus (RSV), which is known to cause pneumonia.

Flus and colds are not spread by touching inanimate objects, such as subway poles or toilet seats. Bacteria or viruses do not thrive on such objects.

Healthy Diet. Daily diets should include foods such as fresh, dark-colored fruits and vegetables, which are rich in antioxidants and other important food chemicals that help boost the immune system.

Low Stress. Interestingly, maintaining an active social lifestyle could help prevent colds. One study found that the more social interaction a person has the less likely they are to have a cold, possibly because stress hormones, which suppress the immune system, are reduced.

Zinc

Zinc preparations using lozenges or nasal gels are now available as cold treatments. Studies are very mixed on the effects of zinc on colds. In 10 controlled studies, five showed no effect on symptoms and five reported that it shortened the duration of cold. And, in fact, in 1999, the FDA charged the manufacturer of the zinc carbonate lozenges Cold-Eeze and Kids-Eeze Bubble-Gum with making unsubstantiated claims about their benefits against colds, allergies, and pneumonia.

The variance observed in studies may be due to different zinc preparations. Studies are underway to determine advantages, if any, but results are still mixed. Some examples include the following:

One 2000 study suggested that the use of zinc acetate lozenges (eg, Fast-Dry, Galzin) may be more effective and have a better taste than other formulations, such as zinc gluconate (Cold-Eeze, Orazinc. In the study, this preparation reduced both duration and severity of symptoms compared to a dummy pill.
The two zinc lozenge preparations were directly compared in another 2000 study, however, and neither were effective.
A nasal zinc gluconate gel (Zicam), which contains zinc ions as the active ingredient, may be more effective than zinc lozenges because the zinc resides within the nasal cavity long enough to interact with the virus. In one 2000 study, patients with colds who used it achieved full recovery in an average of 2.3 days compared to 9 days in patients using a "dummy" nasal preparation. More studies are underway.

Zinc appears to have certain effects on the immune system that dampen the inflammatory response (which causes fever and aches). How it works is not entirely clear, however. In any case, no one with an adequate diet and a healthy immune syst em sho uld take zinc for prolonged periods for preventing colds.

Side Effects. Side effects include the following:

Dry mouth
Constipation
Nausea
Bad taste (possibly only with zinc gluconate lozenges)
Overdose may cause severe vomiting, dehydration, and restlessness. Call a physician if any of these symptoms occur.
In rare cases, an allergic response may occur.

Food and Drug Interactions. Zinc may also interact with drugs or other elements.

It may reduce absorption of certain antibiotics.
Foods high in calcium or phosphorus may reduce zinc absorption.
In high doses and for long periods of time zinc can cause copper deficiencies.

Vitamin C

A number of studies have found that large doses of vitamin C reduce the duration of a cold by 5% to 50%, depending on the study.

Taking large doses of vitamin C after exposure to a cold virus, however, does not appear to prevent the cold from developing. In an examination of 60 studies, the six largest ones reported no preventive effects of vitamin C in well-nourished individuals. (It may be useful for prevention of respiratory infections in people in poor health or under heavy physical stress, however.)

Some precautions against taking high doses of vitamin C include the following:

High doses of vitamin C may cause headaches and intestinal and urinary problems and even kidney stones.
Because ascorbic acid increases iron absorption, people with certain blood disorders, such as hemochromatosis, thalassemia, or sideroblastic anemia, should particularly avoid high doses.
Large doses can also interfere with anticoagulant medications, blood tests used in diabetes, and stool tests.

Echinacea

The herbal remedy echinacea is now commonly taken to prevent onset and ease symptoms of cold or flu. There are three species:

Echinacea (E.) purpurea.
E. pallida.
E. augustifolio .

In some studies, people who took extracts of either E. purpurea or E. augustifolio experienced no protection against colds. Preparations themselves vary, however, and effectiveness may depend on whether the root, herb, or whole plant is used. For example, in a 1999 study, a root and herb preparation of E. purpurea (Echinaforce) reduced cold symptoms while another E. purpurea root preparation did not. The drying process also effects the active chemicals in the herb. (Freeze-drying may be best.) Research is needed to determine which ones, if any, are beneficial.

Precautions. Some precautions are as follows:

At this time there are no standards or quality controls available for echinacea (including what part of the plant to use) or any other herbal remedies.
Allergic reactions have been reported. People with autoimmune diseases or who are allergic to plants in the daisy family should particularly avoid it.
There have been some reports of a reaction called erythema nodosum associated with echinacea. This involves a rash, sometimes accompanied by fever, headache, muscle and joint aches, and sore throat.

No one should take untested so-called natural remedies without a doctor's approval. No studies have confirmed the benefits of these medications and many can cause toxic side effects in large doses.

Vaccines for Haemophilus Influenzae

All children under five should be vaccinated against Haemophilus influenzae. Studies suggest that it is also beneficial for people with illnesses that put them at risk for pneumonia, including sickle cell disease, leukemia, HIV infection, and splenectomies.

Viral Influenza Vaccines

Description of Vaccines. Vaccines are designed to block recognize foreign agents (called antigens) in the body and to attack them. Vaccines against influenza currently employ inactivated (not live) viruses to produce an immune response that will then attack the active virus. Vaccines are given by injection in the fall, usually between October and December. A live but weakened intranasal vaccine (FluMist) should be available soon. It is engineered to grow only in the cooler temperatures of the nasal passages, not in the warmer lungs and lower airways. The vaccine boosts the specific immune factors in the mucous membranes of the nose that fight off the actual viral infections. It is employed using a nasal spray and in one study provided protection against the flu in up to 93% of children.

Annual Redesign. At this time, vaccines must be redesigned each year to match the current strain. This is because both influenza A and B viral strains undergo changes over time (known as antigenic drift or shift), so a vaccine that works one year may not work the next. Influenza A is a particular problem because it can infect other species, such as pigs or chickens, and undergo major genetic reassortments. Influenza B viruses tend to be more stable than influenza A viruses, but they too vary.

Candidates for the Vaccine. The following adults should be vaccinated each year:

All adults 50 years and older, and particularly those in nursing homes.
Pregnant women who will be in their second or third trimester during flu season.
Anyone at risk for serious complications, including people with heart disease, lung problems, immune deficiencies, diabetes, kidney disease, or chronic blood disease.
HIV patients
Health care workers, nursing home employees, and other who may expose high-risk people to the flu.

The following children over six months should be vaccinated against influenza:

Any child with a condition that requires regular medical care.
Any child who has been hospitalized for a serious illness (particularly lung, kidney, diabetes, sickle-cell, or immune deficiencies.)
Children who are receiving long-term aspirin therapy should also be immunized against the flu because they are at higher risk for Reye's syndrome, a life-threatening disease, if they get the flu.

The vaccine may be useful or important in other individuals as well:

People such as firemen or policemen who are critical for public safety.
People at risk for complications of influenza and who are traveling to the tropics at any time or to the Southern Hemisphere between April and September.

The vaccines may be slightly less effective in the elderly, the very young, and patients with certain chronic diseases than in healthy young adults.

Effectiveness and Benefits. The vaccinations protect against influenza in between 70% and 100% of healthy adults when the virus and the vaccine are well matched.

In the absence of a match and among the elderly and children, they are protective in 30% to 60% of people. Even in people with a weaker response, however, the vaccine is usually protective against serious flu complications, particularly pneumonia, if such people get the flu.

Vaccinated older adults have lower hospitalization rates and death from any cause than unvaccinated peers.

Additionally, studies are finding that the more people that are vaccinated, the healthier the community at large. One interesting study in Japan found that vaccinating children actually helps protect the elderly.

Negative Effects. Possible negative responses include the following:

Newer vaccines contain very little egg protein, but an allergic reaction still may occur in people with strong allergies to eggs.
Almost a third of people who receive the influenza vaccine develop redness or soreness at the injection site for one or two days afterward.
Other side effects include mild fatigue and muscle aches and pains; they tend to occur between six and 12 hours after the vaccination and last up to two days. It should be noted that these symptoms are not influenza itself but an immune response to the virus proteins in the vaccine. Anyone with a fever, however, should not be vaccinated until the ailment has subsided.
Some studies have reported more severe asthma symptoms in children with the lung condition. A 2000 study of asthmatic children, however, reported no increased risk. In fact, there was some indication that the vaccination helped reduce asthma attacks over time. More research is needed to confirm or refute these results.

Pneumococcal Vaccines

Experts are now recommending that more people, including healthy elderly people, be given the pneumococcal vaccine, particularly in light of the increase in antibiotic-resistant bacteria. This vaccine does not prevent influenza, but it may help prevent pneumonia in people who are susceptible to sever flus.

Candidates for the Pneumococcal Vaccine. A recently approved pneumococcal vaccine (Prevenar or PCV7) is very effective in children and, some experts believe that universal vaccinations for infants would prevent a million cases of ear infections as well as serious infections, such as pneumonia. In one study, a similar vaccine under investigation protected not only children in day care from serious respiratory infections, but their younger unvaccinated siblings had fewer infections as well.

The pneumococcal vaccine is now recommended by many experts for the following groups:

All children up to age two and certain high-risk children up to age five, such as those at risk for meningitis or widespread infection.
All elderly people.

Special high-risk groups are strongly advised to have pneumococcal vaccinations:

Adults or children who have immune deficiencies (eg, HIV) or are undergoing treatments to suppress the immune system.
Children with sickle-cell disease.
Patients with kidney disease or kidney transplants. Older people who have had transplant operations or those with kidney disease may require a revaccination after six years.
Patients with problems in the spleen.
Alcoholics (especially those with cirrhosis).
Adults or children with any condition that increases the risk for pneumonia. (Those at risk for serious pneumonia should be revaccinated six years after the first dose.)

Protection lasts for over six years in most people, although the protective value may be lost at a faster rate in elderly people than in younger adults.

Antiviral Agents

Antiviral agents have now been developed to treat and prevent influenza A, B, or both. There are two classes of agents: M2 inhibitors and neuraminidase inhibitors.

M2 Inhibitors. Amantadine (Symmetrel) and rimantadine (Flumadine) are M2 inhibitors. They have the following benefits:

Both offer protection against influenza A and prevent severe illness if a person contracting the infection. (To be effective it must be administered within two days of onset.)
They may shorten the duration and lessen the severity of the flu if given within 48 hours of onset of symptoms.

Drawbacks of M2 inhibitors include the following

They are not effective against influenza B (less common but more severe than A).
Viral resistant to these agents is rapidly emerging.
Both agents occasionally cause nausea, vomiting, and indigestion.
Amantadine affects the nervous system and about 10% of people experience nervousness, depression, anxiety, difficulty concentrating, and lightheadedness. Rarely, amantadine can cause hallucinations and seizures, usually in elderly people already at risk for psychiatric symptoms.
Neither has proven to reduce the risk for complications, including pneumonia and bronchitis.

Neuraminidase Inhibitors. Zanamivir (Relenza) and oseltamivir (Tamiflu) are called neuraminidase inhibitors. They are newer agents that have been designed to block a key viral enzyme, neuraminidase, which is involved with viral replication.

They have the following benefits:

Both neuraminidase inhibitors are proving to be effective for treating and preventing A and B strains of influenza. (M2 inhibitors are only effective against type A, although they are also much less expensive than neuraminidase inhibitors.)
They both shorten the duration of the flu by one to three days but need to be taken within two days of onset of symptoms.
A 2000 study on oseltamivir suggested that they may help reduce transmission of the virus.
They appear to have a lower risk than M1 inhibitors for emerging viral strains that are resistant to their effects.
There is some early evidence that they may reduce complications of influenza, although this needs to be confirmed. It is not yet known if they have any effect on overall survival rates.

Both neuraminidase inhibitors provide similar benefits but there are some differences:

Zanamivir is administered as a nasal spray or inhaler. Side effects are minor. People with asthma or other lung disorders may experience airway spasms and should use this drug with caution.
Oseltamivir comes in capsule form. Side effects are also minor but about 10% of patients experience nausea and vomiting.

Their current use in different age and patient groups are as follows:

Adults. Both are approved for treatment in adult patient.
Children. Zanamivir is also approved for children over seven. Studies are currently underway to determine the safety of oseltamivir in children. In one study, it reduced the duration of symptoms by 26% and also reduced incidence of ear infections by 44% in children ages one to 12.
High-Risk Patients. Recent studies indicate they are safe and effective in patients with serious medical problems or other conditions that put them at risk for complications of flu.

Antiviral Agents for Prevention of Influenza. Although they are not substitutes for vaccines, all antiviral agents have some preventive properties.

M2 inhibitors. Amantadine and rimantadine protect against the influenza A infection itself in about half of individuals. Rimantadine is preferred for prevention during outbreaks of influenza A because it has fewer adverse side effects.
The neuraminidase inhibitors. Both agents help prevent both influenza A and B. In one community study, zanamivir protected 30% and oseltamivir 50% of the population for contracting influenza. Protection rates have been even higher in families and nursing home patients exposed to the flu.

Potentially these agents could be used for prevention in the following cases:

In combination with the flu vaccine during season where there is a poor match between the virus and vaccine.
During two-week periods after a vaccination when antibodies are developing and the individual is still vulnerable to the virus.
As supplementary protection for vaccinated people in high-risk groups, such as the elderly or people with compromised immune system.
In people who cannot have vaccinations for whatever reason
For people who prefer and antiviral agent to a vaccine.

To date both M2 inhibitors and oseltamivir have been approved for prevention of influenza.

WHERE ELSE CAN HELP FOR PNEUMONIA BE FOUND?

The American Lung Association and American Thoracic Society, 1740 Broadway, New York, New York 10019-4374. Call (800-LUNG-USA)

Internet sites connected with the American Lung Association are as follows:

American Lung Association (http://www.lungusa.org/)

American Thoracic Society (http://www.thoracic.org/)

Society of Thoracic Surgeons (http://www.sts.org/)

The association is very responsive and offers a wide range of information and services.

National Heart, Lung, and Blood Institute, P.O. Box 30105, Bethesda, MD 20824-0105. Call (301-251-1222) or on the Internet (www.nhlbi.nih.gov/nhlbi/nhlbi.htm)

National Jewish Center for Immunology and Respiratory Medicine, 1400 Jackson Street, Denver, CO 80206. Call (800-222-LUNG or 303-355-LUNG) or for the recorded service Lung Facts call (800-552-LUNG) or on the Internet (www.njc.org) or email a nurse at (lungline@njc)

Centers for Disease Control has a National Immunization Information Hotline. Call (800-232-2522)

Internet Sites

Centers for Disease Control (http://www.cdc.gov/)
The site has excellent in-depth information on all aspects of pneumonia.

Federal Agency for Health Care Policy and Research, (http://www.ahcpr.gov/clinic/pneuclin.htm)
This site provides guidelines for predicting pneumonia.