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Post-influenza Staphylococcus aureus pneumonia — SCE Respiratory MCQ

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HardRespiratory InfectionsPost-influenza Staphylococcus aureus pneumoniaSCE Respiratory

A 72-year-old man with COPD is admitted with influenza A confirmed by PCR. On day 5 he deteriorates with fever, pleuritic pain and new cavitating right upper-lobe consolidation. Sputum Gram stain shows Gram-positive cocci in clusters. What is the most likely underlying cause?

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Correct answer: D — Post-influenza Staphylococcus aureus pneumonia

Influenza followed by rapid deterioration, cavitating pneumonia and Gram-positive cocci in clusters is typical of secondary Staphylococcus aureus pneumonia. Mycoplasma is less likely to cavitate, and Pneumocystis causes diffuse interstitial disease. TB is possible in cavitation but the acute post-influenza course and Gram stain favour S aureus.

Reference: NICE NG250 Pneumonia; BTS CAP Guideline