Case #002

Fever, headache, neck stiffness and confusion are bacterial meningitis, but two details move this away from the pneumococcus that would otherwise head the list. The first is the neurology: nystagmus, facial weakness and a wide-based gait are brainstem signs, and a rhombencephalitis layered on meningitis is close to a signature for Listeria, which reaches the brainstem in a way the common pathogens do not. The second is the fluid, lymphocyte-predominant at 62 per cent rather than the near-pure neutrophilia of pneumococcal disease, with gram-positive rods on the stain where one expects gram-positive diplococci. Age over 50, six years of corticosteroids for rheumatoid arthritis, and a diet of soft cheese and deli meats supply both the susceptibility and the source. The treatment point is what makes this case worth knowing. Listeria carries intrinsic resistance to every cephalosporin, a property of its penicillin-binding proteins rather than something acquired, so the standard empiric pairing of ceftriaxone and vancomycin cannot touch it. Her failure to improve on exactly that regimen is the clue demonstrating it. What she needs is high-dose intravenous ampicillin, an aminopenicillin, usually with gentamicin for synergy and for at least three weeks. It is also why ampicillin is added empirically for anyone over 50, pregnant or immunosuppressed, long before an organism is named. Trimethoprim-sulfamethoxazole covers the penicillin-allergic.