A 74‐year‐old man with left total hip and knee arthroplasties presented with 1 week of ipsilateral back, hip, and knee pain. He was diagnosed with Methicillin‐sensitive Staphylococcal aureus bacteremia, lumbar discitis, psoas abscess, and septic arthritis of the hip and knee requiring explant of hardware. He was treated with intravenous cefazolin while awaiting placement. His early hospital course was notable only for mild antibiotic‐associated diarrhea with a nongap acidosis. On hospital day ten, the patient complained of increasing pain with dressing changes. He then developed progressive shortness of breath. Temperature was 37.9°C, pulse 132, blood pressure 192/82, respirations 32, and oxygen saturation 80% on room air. There was no jugular venous distension. Cardiac and pulmonary exams were otherwise normal, and his surgical incisions looked intact. White blood cell count was 4.1 × 103/μL, and hemoglobin was stable at 7.1 g/dL Sodium was 138 mEq/L, HCO3 3 mEq/L, anion gap 18 mEq/L, creatinine 2.1 mg/dL, glucose 18 mg/dL, AST 229 U/L, ALT <5 U/L, CRP 9.5 mg/dL, and lactate 13.8 mg/dL Arterial blood gas revealed a pH of 7.03 and pCO2 of 11 mm Hg. Electrocardiogram showed sinus tachycardia. Chest radiograph and urinalysis were negative. The patient was transferred to the intensive care unit for severe sepsis and intubated for inadequate respiratory compensation. Repeat skin exam revealed extensive mottling and induration extending from the left hip down the leg and across the back and abdomen, concerning for necrotizing soft‐tissue infection (NSTI). The patient was volume‐resuscitated and his antibiotics broadened to vancomycin, piperacillin/tazobactam, clindamycin, levofloxacin, and micafungin. He was taken emergently to the operating room, where he underwent debridement of 20% of his body surface area. His postoperative course was complicated by refractory shock and multi‐organ failure, and he died shortly thereafter. Blood and wound cultures grew extended‐spectrum beta‐lactamase‐producing Escherichia coli that was sensitive to piperacillin/tazobactam.
Hospitalists frequently care for orthopedic patients with joint infections, but only rarely encounter NSTIs. This patient's surgical wound most likely became contaminated from his ongoing diarrhea. Prompt recognition is critical given the high morbidity and mortality associated with NSTIs. Serial skin examinations are key since physical findings can be subtle despite systemic toxicity. In this case, the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score was misleading and categorized the patient as low risk for NSTI. However, the marked lactic acidosis in the absence of hypotension, along with the disproportionate elevation in AST compared to ALT, quickly brought NSTI to the top of the differential.
Hospitalists should maintain a high index of suspicion for NSTIs, as they represent a life‐threatening emergency.
To cite this abstract:Anderson M, Wang Y. More Than Skin Deep: One Nosocomial Infection Not to Miss. Abstract published at Hospital Medicine 2013, May 16-19, National Harbor, Md. Abstract 382. Journal of Hospital Medicine. 2013; 8 (suppl 2). https://www.shmabstracts.com/abstract/more-than-skin-deep-one-nosocomial-infection-not-to-miss/. Accessed July 16, 2019.