Mycoplasma pneumonia

Alternative names:

primary atypical pneumonia; walking pneumonia

Definition:

An infection of the lungs caused by Mycoplasma pneumoniae.

Causes, incidence, and risk factors:

Pneumonia is a very common serious illness, affecting 1 out of 100 people. It is caused by many different organisms and can range in seriousness from mild to life-threatening illness.

Mycoplasma pneumonia is the most common cause of atypical pneumonia and affects those under 40 most commonly. Various studies suggest that it causes 15-50% of all pneumonia in adults and an even higher percentage of the pneumonia in school-aged children. Symptomatic infection in children less than 4 years of age is uncommon. Mycoplasma pneumonia is frequently spread within the family and may affect all the family members. The incubation period is 1 to 3 weeks.

Symptoms generally appear as an upper respiratory infection and progress to pneumonia or tracheobronchitis. Mycoplasma may also be responsible for a sore throat (pharyngitis) and earache (a specific type called bullous myringitis). Infected individuals often feel much worse than they look. The incidence of Mycoplasma pneumonia is about 4 cases per 1000 individuals per year.