Friendly Kisses Can Be Deadly: Capnocytophaga canimorsus Bacteremia in an Asplenic Patient Exposed to Canine Saliva

Abstract

The differential diagnosis for febrile asplenic patients must always include opportunistic infections. Capnocytophaga canimorsus is one such infection. In this report, we discuss the case of a 73-year-old woman with a medical history significant for splenectomy for splenic sarcoma with prophylactic vaccination for pneumococcus who presented with rigors, emesis, and abdominal pain. Initial vital signs were 39.6°C (103.3°F), 166/70 mmHg, 92 bpm, and 95% SpO ₂ on room air. A physical examination revealed mild epigastric tenderness. Initial labs and imaging were unremarkable. Eight hours after the presentation, she became hypotensive. Repeat labs revealed leukopenia with 51% bands, hemoglobin 11.0 g/dL down from 13.9 g/dL, platelets 74 K/ μL trending down to 15 K/ μL, PT 23.5 sec., aPTT 60.3 sec., D-dimer greater than 20  μg/mL, fibrinogen 190 mg/dL, LDH 1515 IU/L, haptoglobin less than 20 mg/dL, and creatinine 1.84 mg/dL. A peripheral smear showed schistocytes. Blood cultures identified gram-negative rods and Capnocytophaga canimorsus. After further questioning, she recalled her dog licking an abrasion on her left index finger. Four days after the presentation, she developed a purpuric rash on her bilateral hands and feet with areas of Nikolsky's negative bullae along the dorsum of her left foot. She also developed acute renal failure requiring renal replacement therapy and hemodialysis. Capnocytophaga canimorsus is an encapsulated facultative anaerobic gram-negative bacillus. Infection can result in bacteremia and sepsis and carries a high mortality rate, even with treatment. Those with hyposplenism/asplenia are particularly susceptible to infection and can deteriorate quickly, as seen in this case. Although this infection is rare, our case highlights how all asplenic patients must be assessed and treated for encapsulated bacterial infections when presenting with an acute febrile illness, regardless of initial laboratory analysis.