Lethal Waterhouse-Friderichsen syndrome caused by Capnocytophaga canimorsus in an asplenic patient

Abstract

Background: Capnocytophaga canimorsus, a Gram-negative rod, belongs to the Flavobacteriaceae family and colonizes the oropharynx of dogs and cats. Infections with C. canimorsus are rare and can induce a systemic infection with a severe course of the disease. So far, only five case reports of C. canimorsus infections associated with Waterhouse-Friderichsen Syndrome (WFS) have been reported with only two of the patients having a history of splenectomy.

Case presentation: Here, we report a fatal case of WFS due to C. canimorsus bacteremia and mycetal superinfection in a 61-year-old female asplenic patient. Despite extensive therapy including mechanical ventilation, antibiotic coverage with meropenem, systemic corticosteroids medication, vasopressor therapy, continuous renal replacement therapy, therapeutic plasma exchange, multiple transfusions of blood products and implantation of a veno-arterial extracorporeal membrane oxygenation the patient died 10 days after a dog bite. The autopsy showed bilateral hemorrhagic necrosis of the adrenal cortex and septic embolism to heart, kidneys, and liver. Diagnosis of C. canimorsus was prolonged due to the fastidious growth of the bacteria.

Conclusions: The occurrence of a severe sepsis after dog bite should always urge the attending physician to consider C. canimorsus as the disease-causing pathogen. A therapeutic regimen covering C. canimorsus such as aminopenicillins or carbapenems should be chosen. However, despite maximum therapy, the prognosis of C. canimorsus-induced septic shock remains very poor. Asplenic or otherwise immunocompromised patients are at higher risk for a severe course of disease and should avoid exposure to dogs and cats and consider antibiotic prophylaxis after animal bite.

Keywords: Capnocytophaga canimorsus; Case report; Dog bite; Waterhouse–Friderichsen Syndrome; sepsis.

Fig. 1

Timeline of the episode of care

Fig. 2

Clinical presentation of Waterhouse–Friderichsen syndrome by Capnocytophaga canimorsus. a The patient presented with facial purpura as well as b perioral and acral necrosis

Fig. 3

Hemorrhage of the adrenal gland with areas of necrosis using hematoxylin–eosin stain. Microscopy images were taken with a Leica DM5500 B microscope (Leica, Wetzlar, HE, Germany; 20 × magnification), images were captured on a CCD camera and adjusted with DISKUS program

Fig. 4

Culture of Capnocytophaga canimorsus. a Gram-staining of C. canimorsus from blood culture showing subtle Gram-negative rods. The image was taken with a Leica CM750 microscope (1000 × magnification) and captured with a camera attached to the microscope (Leica DMshare software). b Growth of C. canimorsus on Columbia blood agar revealing small, greyish, sharply defined colonies after 48 h

Fig. 5

Growth of Capnocytophaga canimorsus on Columbia blood agar of two different manufacturers. Positive blood cultures were inoculated on Columbia Agar with 5% sheep blood from (a) BD and (b) Oxoid. The inoculum of pure cultures was standardized (McFarland 0.5) and sub-cultured on Columbia blood agar from (c) BD and (d) Oxoid. The comparison of the media from two manufacturers revealed a (b) weaker or (d) absent growth on agar plates from Oxoid