Hemophagocytic syndrome with severe sepsis caused by Capnocytophaga canimorsus

Purpura fulminans secondary to Capnocytophaga canimorsus bacteraemia following a dog bite: A case report and review of literature

Introduction

Infection due to Capnocytophaga canimorsus may result in a wide variety of clinical presentations. We present a case of life-threatening Capnocytophaga canimorsus infection with evolution of ecchymosis to purpura fulminans.

Case description

We present a case of a 43-year-old male with a history of excessive alcohol consumption who presented with features of sepsis following a dog bite. This was associated with a striking, widespread purpuric rash. A causative pathogen, C. canimorsus was identified through blood culture and 16S RNA sequencing. His initially purpuric rash underwent bullous transformation and was diagnosed clinically as purpura fulminans, confirmed on skin biopsy. He made a full recovery with prompt antimicrobial therapy, initially with co-amoxiclav but escalated to clindamycin and meropenem due to clinical deterioration and concerns of beta-lactamase resistance.

Discussion

β-Lactamase producing Capnocytophaga strains are of increasing concern. This particular concern is reflected in our case as 5 days into treatment with β-lactamase inhibitor combination therapy the patients clinical condition deteriorated but demonstrably improved on switching to a carbapenem.The development of biopsy proven purpura fulminans in this immunocompetent case is a rare severe manifestation of the previously reported manifestation of disseminated intravascular coagulation (DIC) in Capnocytophaga bacteraemia. The case reported describes characteristics common with other DIC presentations such as the presence of clinical risk factors (history of excessive alcohol consumption) and symmetrical involvement. However, an unusual feature in that initial purpuric lesions were followed by the development of a bullous appearance and peripheral necrotic features concerning for purpura fulminans and confirmed with skin biopsy.

Waterhouse-Friderichsen syndrome following a dog bite in an asplenic patient: case report and review of the literature

The Waterhouse-Friderichsen syndrome represents a critical condition characterized by a septic shock associated with a disseminated intravascular coagulation causing the plugging of the microvascular network virtually all organs and systems, including the skin, the kidneys, the liver, and adrenal glands; the mortality rate is elevated, and survivors often must undergo multiple limb amputations. Here, we describe the uncommon case of an asplenic patient who developed this syndrome after a superficial wound caused by a dog bite causing an initial infection due to Capnocytophaga canimorsus that is part of the normal oral microbiome of pets. The clinical and pathological findings and the current and future therapeutic options are reviewed and discussed.

Bilateral acute renal cortical necrosis after a dog bite: case report

Background

Capnocytophaga canimorsus is a Gram-negative capnophilic rod and part of dogs/cats’ normal oral flora. It can be transmitted by bites, scratches, or even by contact of saliva with injured skin. Asplenic patients and patients with alcohol abuse are at particular risk for fulminant C. canimorsus sepsis. However, also immunocompetent patients can have a severe or even fatal infection. This is the first case of a severe C. canimorsus infection in an immunocompromised host complicated by acute renal cortical necrosis with a “reverse rim sign” in contrast-enhanced computed tomography on hospital admission.

Case presentation

We report the case of a 44-year functionally asplenic patient after an allogeneic stem cell transplantation, who presented with septic shock after a minor dog bite injury 4 days prior. Because of abdominal complaints, epigastric pain with local peritonism, and radiological gallbladder wall thickening, an abdominal focus was suspected after the initial work-up. The patient underwent emergent open cholecystectomy, but the clinical suspicion of abdominal infection was not confirmed. Septic shock was further complicated by cardiomyopathy and disseminated intravascular coagulation. As a causative pathogen, C. canimorsus could be isolated. The clinical course was complicated by permanent hemodialysis and extensive acral necrosis requiring amputation of several fingers and both thighs.

Conclusion

We present a severe case of a C. canimorsus infection in a functionally asplenic patient after a minor dog bite. The clinical course was complicated by septic shock, disseminated intravascular coagulation, and the need for multiple amputations. In addition, the rare form of acute renal failure - bilateral acute renal cortical necrosis – was visible as “reverse rim sign” on computed tomography scan. This case is an example of the potential disastrous consequences when omitting pre-emptive antibiotic therapy in wounds inflicted by cats and dogs, particularly in asplenic patients.