An 80-year-old woman presents to the emergency room with cough, pleuritic chest pain, and shortness of breath. Her cough is productive of purulent sputum. The patient had been ill for 1 wk with what her private physician had diagnosed as influenza, but for the last 2 days she has been afebrile and asymptomatic and thought “the flu was over.” The patient is febrile, tachycardic, and tachypneic. Lung auscultation reveals increased fremitus, egophony, dullness, and crackles at the right base. Chest radiograph reveals a right lower lobe area of consolidation. Which of the following is the most likely diagnosis?
a. Bacterial pneumonia
b. Pulmonary embolus
c. Lung abscess
d. Bronchiectasis
e. Asthma
a. Bacterial pneumonia (Fauci, 14/e, pp 1112–1116.)
Secondary bacterial infection may be a complication of acute influenza. The common pathogens are Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae. Often the patient experiences improvement in the influenza symptoms prior to the development of the bacterial pneumonia. A sputum gram stain or sputum culture is often helpful because patients may have a primary influenza viral pneumonia (the most common complication of influenza) or a mixed viral-bacterial pneumonia.