Atypical pneumonia

Answer 1

Definition

Atypical pneumonia refers to pneumonia caused by certain bacteria, including Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae.

This article provides a general overview of atypical pneumonia.

See also:

• Legionella pneumonia (Legionnaire's disease)
• Mycoplasma pneumonia

Alternative Names

Walking pneumonia; Chlamydophila pneumoniae

Causes, incidence, and risk factors

Atypical pneumonia due to mycoplasma and chlamydophila bacteria usually cause mild forms of pneumonia, unlike other types of the disease that can come on more quickly with more severe early symptoms.

Mycoplasma pneumonia often affects younger people and may be associated with anemia, certain types of rashes, and neurological conditions such as meningitis, myelitis, and encephalitis. For more information on this type of pneumonia, see: Mycoplasma pneumonia

Pneumonia due to chlamydia-related bacteria occurs year round and accounts for 5 - 15% of all pneumonias. It is usually mild with a low Death Rate.

Atypical pneumonia due to Legionella accounts for 2 - 6% of pneumonias and has a higher death rate. Older adults, smokers, and those with chronic illnesses and weakened immune systems are at higher risk for this type of pneumonia. Breathing in contaminated air (such as that from infected air conditioning systems) has also been linked to pneumonia due to Legionella. For more information on this type of pneumonia, see: Legionnaire's disease

Symptoms

• Chills
• Confusion (especially with Legionella pneumonia)
• Cough
• Diarrhea (especially with Legionella pneumonia)
• Fever
• General ill feeling
• Headache
• Loss of appetite
• Muscle stiffness and aching
• Rapid breathing
• Rash (especially with mycoplasma pneumonia)
• Shortness of breath

Signs and tests

Persons with suspected pneumonia should have a complete medical evaluation, including a thorough physical exam and a chest x-ray -- especially since the physical exam may not always distinguish pneumonia from acute bronchitis or other respiratory infections.

Depending on the severity of illness, additional studies may be done, include:

• Complete blood count (CBC)
• Blood cultures
• Blood tests for antibodies to specific bacteria
• Bronchoscopy
• Open lung biopsy (only done in very serious illnesses when the diagnosis cannot be made from other sources)
• Sputum culture

Urine tests or a throat swab may also be done.

Treatment

Antibiotics are used to treat atypical pneumonia. If you have a mild case, you may be able to take antibiotics by mouth. If you have severe atypical pneumonia, you will likely be admitted to a hospital where you will be given antibiotics through a vein (intravenously), as well as oxygen.

Antibiotics used to treat atypical pneumonia include:

• Azithromycin
• Clarithromycin
• Erythromycin
• Fluoroquinolones and their derivatives (such as levofloxacin)
• Tetracyclines (such as doxycycline)

Expectations (prognosis)

Most patients with pneumonia due to mycoplasma or chlamydophila do well with appropriate antibiotic therapy, although there is a small chance that the infection will return if antibiotics are used for fewer than 2 weeks.

While atypical pneumonias are commonly associated with milder forms of pneumonia, pneumonia due to Legionella, in particular, can be quite severe, especially among the elderly and those with chronic diseases and weakened immune systems. It is associated with a higher death rate.

Complications

• Hemolytic anemia (especially with mycoplasma pneumonia)
• Lung failure

Calling your health care provider

Contact your health care provider if you develop fever, cough, or shortness of breath. There are numerous causes for these symptoms. The doctor will need to rule out pneumonia.

Prevention

There is no known prevention for atypical pneumonia. No vaccine is available at this time for atypical pneumonia.

References

Limper AH. Overview of pneumonia. In: Goldman L, Ausiello D. Cecil Medicine. Philadelphia, Pa: Saunders; 2007:chap 97.

Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007;44:S27-S72.

Answer 2

Definition

Atypical pneumonia refers to pneumonia caused by certain bacteria, including Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae.

Pneumonia is a condition in which there is an infection of the lung.

Alternative Names

Walking pneumonia; Chlamydophila pneumoniae; Community-acquired pneumonia - atypical

Causes, incidence, and risk factors

Mycoplasma pneumonia is a type of atypical pneumonia. It is caused by the bacteria M. pneumoniae. It typically affects people younger than age 40. For more information on this type of pneumonia, see: Mycoplasma pneumonia

Pneumonia due to chlamydia-related bacteria occurs year round and accounts for 5 - 15% of all pneumonias. It is usually mild.

Pneumonia due to Legionella is seen more often in middle-aged and older adults, smokers, and those with chronic illnesses or a weak immune system.

See also: Legionnaire's disease

Symptoms

Pneumonia due to mycoplasma and chlamydophila bacteria is usually mild.

• Pneumonia due to Legionella pneumophila gets worse during the first 4 - 6 days, and then improves over 4 - 5 days.
• Even though symptoms will improve, it may take a while for them to go away completely.

The most common symptoms of pneumonia are:

• Chills
• Cough (with Legionella pneumonia, you may cough up bloody mucus)
• Fever, which may be mild or high
• Shortness of breath (may only occur when you climb stairs)

Other symptoms include:

• Chest pain that gets worse when you breathe deeply or cough
• Confusion, especially in older people or those with Legionella pneumonia
• Headache
• Loss of appetite, low energy, and fatigue
• Muscle aches and joint stiffness
• Sweating and clammy skin

Less common symptoms include:

• Diarrhea (especially with Legionella pneumonia)
• Ear pain (with mycoplasma pneumonia)
• Eye pain or soreness (with mycoplasma pneumonia)
• Neck lump (with mycoplasma pneumonia)
• Rash (with mycoplasma pneumonia)
• Sore throat (with mycoplasma pneumonia)

Signs and tests

Persons with suspected pneumonia should have a complete medical evaluation. It may be hard for your health care provider to tell whether you have pneumonia or bronchitis, so you may need a chest x-ray. Depending on the severity of the illness, other tests may be done, including:

• Complete blood count (CBC)
• Blood cultures
• Blood tests to identify the bacteria
• Bronchoscopy(rarely needed)
• CT scan of the chest
• Open lung biopsy (only done in very serious illnesses when the diagnosis cannot be made from other sources)
• Sputum culture

Urine tests or a throat swab may also be done.

Treatment

Take these steps at home:

• Control your fever with aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs, such as ibuprofen or naproxen), or acetaminophen. DO NOT give aspirin to children.
• Do not take cough medicines without first talking to your doctor. Cough medicines may make it harder for your body to cough up the extra sputum.
• Drink plenty of fluids to help loosen secretions and bring up phlegm.
• Get a lot of rest. Have someone else do household chores.

Antibiotics are used to treat atypical pneumonia.

• You may be able to take antibiotics by mouth at home.
• If you have severe atypical pneumonia, you will likely be admitted to a hospital, where you will be given antibiotics through a vein (intravenously), as well as oxygen.
• Antibiotics are used for 2 weeks or more

Antibiotics used to treat atypical pneumonia include:

• Azithromycin
• Clarithromycin
• Erythromycin
• Fluoroquinolones and their derivatives (such as levofloxacin)
• Tetracyclines (such as doxycycline)

Expectations (prognosis)

Most patients with pneumonia due to mycoplasma or chlamydophila do well with the right antibiotic therapy. P.Legionella can be severe, leading to problems such as kidney failure, Diabetes, COPD, a weak immune system, and death.

Complications

• Brain and nervous system infections, such as meningitis, myelitis, and encephalitis
• Hemolytic anemia, a condition in which there are not enough red blood cells in the blood because the body is destroying them
• Severe lung damage

Calling your health care provider

Contact your health care provider if you develop fever, cough, or shortness of breath. There are numerous causes for these symptoms. The doctor will need to rule out pneumonia.

Prevention

Wash your hands often and have other people around you do the same.

If your immune system is weak, stay away from crowds. Ask visitors who have a cold to wear a mask.

Get a flu shot every year. Ask your doctor if you need a pneumonia vaccine.

References

Baum SG. Mycoplasma pneumoniae and atypical pneumonia. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 184.

Reviewed By

Review Date: 09/15/2010

Denis Hadjiliadis, MD, Assistant Professor of Medicine, Division of Pulmonary, Allergy and Critical Care, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.