Mycoplasma pneumoniae - Clinical manifestation, URTI, LRTI, Pneumonia, Extra Pulmonary Infections

Clinical manifestation of Mycoplasma pneumoniae

Mycoplasma pneumoniae infects the respiratory tract in humans. The majority of these infections are mild and self-limiting.

The clinical manifestations of Mycoplasma pneumoniae include respiratory infections and extra-pulmonary infections.

Respiratory infections of Mycoplasma pneumoniae

Mycoplasma pneumoniae respiratory infection causes:

1. Upper respiratory tract (URT) infections

2. Lower respiratory tract (LRT) infections

3. Primary atypical pneumonia

URT infections

Upper respiratory tract (URT) infections caused by Mycoplasma pneumoniae occur mostly in school-aged children. Symptoms include low-grade fever, malaise, headache, and non-productive cough (which appears 2-3 weeks after exposure).

The cough is initially non-productive but later may produce small to moderate quantities of sputum which may become mucopurulent and in severe cases be blood-tinged. Runny nose, pharyngitis, coryza, may also occur.

LRT infections (In adolescents or young adults)

Lower respiratory tract (LRT) infections caused by Mycoplasma pneumoniae include tracheobronchitis and bronchopneumonia. The condition is characterized by primary infection of the bronchi with infiltration of bronchial epithelial cells by lymphocytes and plasma cells. Other symptoms include a non-productive cough, fever, malaise, pharyngitis, myalgias, and pneumonia.

Primary atypical pneumonia

Primary atypical pneumonia is also known as walking pneumonia. The incubation period of 2-3 weeks as patients usually do not appear ill, hence the name walking pneumonia.

Once infected with Mycoplasma pneumoniae, the pharynx becomes edematous without any cervical adenopathy and is associated with the presence of patchy broncho-pneumonia seen on chest X-ray. Infection is usually self-limiting but in 5-20% of patients, pleural effusion may occur.

Extra-pulmonary infections

Extra-pulmonary infections, caused by Mycoplasma pneumoniae, show syndromes including myocarditis and pericarditis-cardiac abnormalities, neurological abnormalities, otitis media, and erythema multiforme (Stevens-Johnsons syndrome). Rash, arthritis, encephalitis, and hemolytic anemia are other symptoms of the infection.

The infection causes severe disease in children suffering from Immuno-suppressive disease, individuals with sickle cell anemia, functional asplenia, and children with Down syndrome.