INTRODUCTION: We present a rare case of severe sepsis with purpura fulminans and multi-organ dysfunction from Capnocytophaga canimorsus following a dog bite in a patient without known risk factors.
CASE PRESENTATION: 48 year old white man with no significant past medical history presented to the Emergency Department with nausea, vomiting, abdominal pain, fever and numbness in his legs 24 hours after a dog bite. He rapidly developed respiratory distress requiring intubation and mechanical ventilation. He was febrile with marginal blood pressure requiring fluid resuscitation. Physical exam was significant for cyanosis of the lips, dry mucous membranes, dog bite on the right hand and positive Babinski with negative meningeal signs. Labs showed WBC-17, H/H-15.5/44.3, plt-9,000, BUN-35, creat-3.7, serum lactate of 7.4, the rest of metabolic panel was within normal limits. He developed DIC within a day of his presentation associated with purpuric skin rash. Peripheral smear showed abundant Gram negative bacilli within the neutrophils and extracellularly. Broad spectrum antibiotics were started early upon presentation. His ICU course was complicated by non ST elevation MI with peak Troponin I level of 8.79 and disseminated intravascular coagulation (DIC). His renal function deteriorated further requiring hemodialysis. Both blood cultures drawn on the day of presentation grew Capnocytophaga canimorsus which was identified by DNA sequencing. Antibiotics were de-escalated to ceftriaxone and levofloxacin. The patient received platelet and blood transfusions for DIC and was treated with plasmapheresis for a total of 4 sessions. He improved dramatically within 2 weeks of his presentation with resolution of renal failure and hematologic abnormalities. On follow up visit in the clinic the patient had complete resolution of all symptoms and regained his baseline functional status.
DISCUSSIONS: Capnocytophaga canimorsus is a fastidious gram-negative rod that is present in the normal oral flora of dogs and cats. It was first isolated by Butler and colleagues in 1977 from a patient with a dog bite. It can cause fulminant sepsis, meningitis and endocarditis. Risk factors include chronic lung disease, splenectomy, immunosuppression and alcoholism. The mortality rate for C. canimorsus septicemia is 30–36%. The increasing frequency of C. canimorsus may be related to more pet owners, greater animal bites and enhanced lab techniques to isolate the organism. C. canimorsus should be suspected in any case following a dog bite as prompt therapy especially in high risk population may prevent a potentially fatal course. Due to the slow growth of this bacterium in culture, C. canimorsus is often difficult to isolate and identify, therefore Gram-staining of a peripheral blood smear may provide an early diagnosis thus avoiding delay before appropriate antibiotic therapy is started.
CONCLUSION: A dog bite leading to septicemia is rare in the normal population. Clinicians should consider C. canimorsus in patients presenting with sepsis and a history of dog bite or animal exposure. Since the organism grows slowly, the clinical laboratory should be alerted to its potential presence. Finally, physicians should inform patients with immune suppression and splenectomy that dogs or animal contact can be important risk factors for Capnocytophaga.
DISCLOSURE: S Martin, None.