A 20-year-old woman presents with headache, fever, and neck stiffness. On examination, her blood pressure is 100/70 mm Hg, pulse 100/min, temperature 38.6, and the neck is stiff and painful to flex and extend. The ears, throat, and sinuses are normal, there are no focal neurologic signs, and the remaining examination is normal. There are no reported similar cases in the community. Which of the following is the most likely source of her infection?
High-Yield Explanation
S. pneumoniae colonizes the nasopharynx of 5-10% of healthy adults and up to 20-40% of children. The source of pneumococcal meningitis is either direct extension from middle ear or sinus infections, or via seeding from a bacteremia. In the latter circumstance, bacteremia from pneumonia would be more likely than from infective endocarditis.