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A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M.; 2013.

A.D.A.M. Medical Encyclopedia.

Atypical pneumonia

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

Last reviewed: August 30, 2012.

Atypical pneumonia refers to pneumonia caused by certain bacteria, including Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae. It is called “atypical” because the symptoms differ from those of pneumonia due to other common bacteria.

Pneumonia is an infection of the lung.

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. It can be more severe.

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:

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:

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:

Expectations (prognosis)

Most patients with pneumonia due to mycoplasma or chlamydophila do well with the right antibiotics. Legionella pneumonia can be severe, leading to problems in patients with kidney failure, diabetes, COPD, and a weak immune system. It can lead to death.

Complications

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

  1. Limper AH. Overview of pneumonia. In: Goldman L, Schafer AI,eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 97.
  2. Mandell LA, Wunderink RG, Anzueto A, et al. InfectiousD iseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007;44:S27-S72. [PubMed: 17278083]
  3. Torres A, Menendez R, Wunderink R. Pyogenic bacterial pneumonia and lung abscess. In: Mason RJ, VC Broaddus, Martin TR, et al, eds. Murray and Nadel’s Textbook of Respiratory Medicine. 5th ed. Philadelphia, Pa:Saunders Elsevier; 2010:chap 32.

Review Date: 8/30/2012.

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. 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. Health Solutions, Ebix, Inc.

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The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

What works?

  • Initial antibiotic treatment for coverage of 'atypical' pathogens for community‐acquired pneumonia in hospitalized adultsInitial antibiotic treatment for coverage of 'atypical' pathogens for community‐acquired pneumonia in hospitalized adults
    Pneumonia is a serious lung infection and is usually treated with antibiotics. Bacteria which cause community‐acquired pneumonia (CAP, pneumonia contracted outside healthcare settings) are traditionally divided into 'typical' and 'atypical', each dictating a different antibiotic treatment. Atypical bacteria include, Legionella pneumophila (L. pneumophila), Mycoplasma pneumoniae (M. pneumoniae) and Chlamydia pneumoniae (C. pneumoniae). The main 'typical' agent causing CAP is Streptococcus pneumoniae (S. pneumoniae). It is usually not possible to determine which of the many potential agents is the cause of CAP, so that antibiotic treatment is empirical, customarily covering both typical and atypical bacteria. While typical coverage is essential, the necessity of the atypical coverage has not been proven. In the previous version of this review we showed that there was no advantage to the atypical arm. Given the persisting inconsistency between current guidelines for treatment of pneumonia and the available evidence, we undertook to update this systematic review.
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