[Septic shock with purpura fulminans after a dog bite]

A 61-year-old man presented with a four-day history of back pain and nonspecific abdominal pain. His condition had significantly worsened since the day before admission with generalized weakness and dyspnea. His temperature was 39.1 C, he had tachycardia and was tachypneic. Peripheral cyanosis was noted. The abdomen was soft with mild epigastric tenderness. A diffuse skin rash developed with increasing petechial bleeding and central necrosis. It was revealed that he had been bitten by a dog several weeks before admission.

Laboratory data indicated an acute inflammatory process with a marked increase in white blood cells and C-reactive protein. An elevated procalcitonin level suggested a systemic bacterial infection. Chest X-ray and abdominal CT scan were unremarkable. Echocardiography revealed a globally hypokinetic heart with no evidence of valvular vegetations. One set of blood cultures grew micro-aerophilic, Gram-negative rods. Gene sequencing identified the slow growing, fastidious bacillus as CAPNOCYTOPHAGA CANIMORSUS.

The patient was admitted to the intensive care unit and initially treated with intravenous piperacillin/tazobactam and hydrocortisone for septic shock. Transfusions of platelets and blood products were given because of disseminated intravascular coagulation. The patient developed multi-organ failure requiring ventilation and hemodialysis; he died four days after admission.

As a rare cause of septicemia, especially in immunocompromised patients, Capnocytophaga canimorsus infection should be considered after an animal bite. Given the slow growth of this bacterium in culture, Gram-staining of a peripheral blood smear may provide an early diagnosis and avoid delay before appropriate antibiotic therapy, which may favorably influence the potentially fatal course, is started.