UMEM Pearls

What's the Diagnosis?

Answer

Lung Abscess (from septic pulmonary emboli)

Discussion

• Lung abscess is necrosis of lung parenchyma with pus and debris-filled cavities.

• It is caused by direct injury (e.g., aspiration pneumonia) or secondary causes (e.g., tricuspid endocarditis, bacteremia, etc.).

• Suspect with: o Loss of airway reflexes (e.g., CVA, seizures, alcohol / narcotic abuse, etc.) o Poor dentition o Immunosuppression o IVDA

• Gram positives, negatives and anaerobic bacteria have all been implicated.

• Chest X-ray may suggest diagnosis, but CT scan better identifies abscess, necrotic tissue, empyema, or other pathology (see image above).

• After drawing blood cultures, broad-spectrum antibiotics should be started and narrowed once culture data is available; address underlying cause (e.g., valve replacement for endocarditis).

• Prognosis is generally good with normal immune function and antibiotics, but mortality sharply increases with immunocompromise and treatment delay.

REFERENCE:

• Mansharamani N, et al. Lung abscess in adults: clinical comparison of immunocompromised to non-immunocompromised patients. Respiratory Medicine. Mar 2002;96(3):178-85