Alternate Names: Walking pneumonia - atypical pneumonia

Causes and Risks:

Atypical pneumonia is caused by a variety of organisms. Often, the cause is not ever discovered. However, the following bacterial or viral organisms may cause it: Mycoplasma pneumoniae, adenovirus, Legionella, Chlamydia and Coxiella Burretti (Q fever).

The incidence of atypical pneumonia is dependent on the patient and the patient’s environment. For instance, mycoplasma and chlamydia pneumonias are spread by close contact (i.e. military barracks or college dormitories). Other factors that predispose individuals to atypical pneumonias are chronic illnesses, especially respiratory illnesses (i.e. bronchitis, emphysema, COPD), and a history of smoking. Also, use of chronic immunosuppressants like steroids tend to make people more susceptible to infection.

Prevention:

Prevention is accomplished largely by minimizing exposure to sick individuals and modifying the patient’s risk factors. For instance, patients who smoke must quit to decrease risk for an atypical pneumonia. Patients who suffer from chronic illness must take their prescribed medications.

FAQ (Frequently Asked Questions)

What is the difference between regular pneumonia and atypical pneumonia?

‘Classic’ pneumonia presents suddenly with fevers, chills and a cough productive of green sputum, whereas atypical pneumonia has a slower onset, with low-grade fevers and a dry cough. The cause of ‘classic’ pneumonia is bacterial and requires antibiotics for full recovery.

My doctor said I have atypical pneumonia; don’t I need antibiotics?

Not necessarily. Most cases of atypical pneumonia will improve with rest and fluids. Antibiotics are used when a severe bacterial infection is suspected, if the patient has a chronic disease or is immunosuppressed.

References:

Rakel: Conn’s Current Therapy 1999, 51st ed., Copyright © 1999 W. B. Saunders Company

Tierny, LM, S.J. McPhee, and M.A. Papadakis. CURRENT: Medical diagnosis and Treatment. 37^th edition. 1998.

Symptoms:

• chills
• dry cough
• headache
• muscular stiffness and aching
• breathing, rapid may be present
• shortness of breath may be present
• loss of appetite (anorexia)
• fevers
• joint pain

Signs and Tests:

Since many different agents cause atypical pneumonia, there are numerous signs that suggest one type of infection to be more likely than another.

Common findings:

• fever
• pharyngitis - red/sore throat
• wheezes or crackles on lung exam
• lymphadenopathy
• dry cough

A routine physical exam will be preformed with a check of your oxygenation level with a device called a pulse oximeter.

Laboratory tests and x-rays may not be very helpful, but they will be sent in a patient who is very ill. Urine or blood tests can diagnose certain infections. X-ray is rarely helpful in diagnosing atypical pneumonia, except in that it rules out other causes to the patien’s symptoms.

Treatment:

Mild cases will not require medication other than over-the-counter medications for symptomatic relief. Rest and intake of fluids will hasten the recovery period. Antibiotics are reserved for more severe infections, or those infections that are caused by bacteria. Antibiotics are NOT currently helpful for viral atypical pneumonia. In fact, unnecessary antibiotic use may be detrimental in the long run because this practice can breed resistance to bacteria.

Prognosis:

Most patients will respond to conservative management, including fluids, rest, and over the counter medications. The typical course of the illness is approximately 2 weeks. Patients with more serious infections will require antibiotics. If there is evidence of extreme fatigue or difficulty breathing, admission to the hospital may be required.

Complications:

Complications are rare, but those individuals with severe infections can require intensive care unit treatment and are at risk for death.

Call for an appointment with your health care provider if unexplained symptoms are present.