Clinical case
A 47 years old male with diabetes mellitus, hypertension, coronary artery disease (underwent percutaneous coronary intervention few years ago), and has alcohol related chronic liver disease had an episode of acute febrile illness two weeks ago. Now admitted with swelling of the right knee since two weeks. Total blood leukocyte count -16,500/mcL, Serum procalcitonin - >100. Synovial fluid cells -13,753/mcL N93%. Synovial fluid culture - no growth, GeneXpert - Negative. 2D Echo - Severe LV dysfunction. Blood culture flagged positive.
Give your diagnosis in the comments below:
Blood culture grew Streptococcus dysgalactiae, a group C streptococcus (GCS) which had a Penicillin MIC of <0.06mcg/ml. A commensal of skin and upper respiratory tract, GCS carries a mortality rate of up to 25% when bacteremia is present. Bacteremia mostly develops in patients with underlying co-morbidities like malignancies or chronic liver disease, following an initial infection episode, and can secondarily lead to septic arthritis as seen in the above case. Skin eruption associated with GCS bacteremia is an uncommon phenomenon, with varying morphologies and histopathological appearances and is likely toxin mediated.
The above patient's antibiotics were de-escalated from cefoperazone-sulbactam + clindamycin to Ampicillin.
Take home: 1. Every case of high procalcitonin levels is not a GNB bacteremia 2. Streptococcus dysgalactiae can present with widespread itchy skin eruptions which can be granulomatous on histopathological examination.
Septic arthritis due to staphylococcus with IE