Mycoplasma pneumoniae Infection

Endemic/pandemic worldwide every 3–5 y.

• Outbreaks likely during summer and early fall.

• Affects persons of all ages.

• Long incubation periods of 1–3 wk.

• Transmitted person to person via aerosols.

• Frequent in closed and semiclosed communities.

Common cause of upper and lower respiratory infections.

• Up to 40% of community-acquired pneumonias, “walking pneumonia.”

• Up to 5% of bronchiolitis in children.

• 3–10% of adults may develop bronchopneumonia.

• Clinical manifestations similar to Chlamydophila pneumonia, Streptococcus pneumonia, and respiratory viruses.

• Fulminant pneumonia may occur in children with sickle cell disease (functional asplenism), Down syndrome, and immunosuppressive conditions.

Extrapulmonary complications in 25% of pts infected with Mycoplasma pneumoniae.

No periop risk data; hemolytic anemia, DIC, and cross-reacting cold agglutinins are of concern, especially if CPB is required.

Hyper-reactive airway disease.

Multisystem organ dysfunction

Clinical manifestations of respiratory involvement are mediated by activity of cytoadherence on the airway epithelium and include

• Sore throat, hoarseness, fever, cough (pertussis-like).

• May play a role in asthma, COPD.

• Conjunctivitis, headache, chills, coryza, myalgias, earache, and generalized malaise are common.

Extrapulmonary manifestations are the result of direct invasion or immune reactivity.

Dx:

• Hx and clinical manifestations: Unspecific upper respiratory symptoms.

• CXR: Diffuse reticular infiltrates in perihilar and lower lobe regions; bilateral in 20% of cases.

• Pathology: Ulceration, edema, ciliary loss, bronchioalveolar inflammatory cell infiltration.

• Culture: Incubation period of several wk; sensitivity around 60%; not practical for routine diagnosis.

• Serology: Current or recent infection likely if antibody titer increase ≥fourfold.

• Cold agglutinins: IgM within 1–2 wk after initial infection; titers ≥1:32 correlate with severity of lung involvement.

• PCR: RNA-amplification techniques are highly sensitive and indicate viable bacterium.