What question did this study set out to answer?

This case presents a rare instance of fulminant Capnocytophaga canimorsus sepsis mimicking atypical hemolytic uremic syndrome.

May 20, 2026

A50-52 A Fulminant Case of Capnocytophaga Canimorsussepsis Presenting as Atypical Hemolytic Uremic Syndrome and Symmetric Peripheral Gangrene

Key Points

This case presents a rare instance of fulminant Capnocytophaga canimorsus sepsis mimicking atypical hemolytic uremic syndrome.
Case report detailing a 66-year-old woman with a history of pet exposure and presenting symptoms
Diagnostic imaging and laboratory tests confirmed acute liver and renal failure alongside blood cultures for C. canimorsus
Treatment included broad-spectrum antibiotics and eculizumab for suspected aHUS.
Patient developed significant multi-organ failure and progressive peripheral gangrene despite treatment
Initial laboratory findings included severe thrombocytopenia and elevated liver enzymes
Ultimately transitioned to comfort measures due to clinical decline.

Abstract

Abstract Introduction Capnocytophaga canimorsus is a gram-negative rod, often found in the saliva of healthy dogs and cats. While typically associated with immunocompromised patients or those with asplenia, it can rarely cause fulminant sepsis in immunocompetent individuals. This case highlights a catastrophic presentation of C. canimorsus infection mimicking a thrombotic microangiopathy (TMA) and leading to severe multi-organ failure and symmetric peripheral gangrene. Case Description A 66-year-old woman with emphysema and malnutrition presented with abdominal pain, nausea, and vomiting after potential exposure to unclean water and multiple household pets. Initial examination revealed lethargy, jaundice, and petechiae. Labs were significant for acute liver failure (aspartate aminotransferase (AST)/alanine aminotransferase (ALT) 829/343), acute renal failure, lactic acidosis, and severe thrombocytopenia (nadir 10). Computed tomography angiography (CTA) of the chest showed a right lower lobe consolidation. Blood cultures grew Capnocytophaga canimorsus. The patient’s course was complicated by worsening encephalopathy requiring mechanical ventilation and acute tubular necrosis (ATN) requiring continuous renal replacement therapy (CRRT). Due to severe thrombocytopenia and suspected microangiopathic hemolytic anemia, thrombotic thrombocytopenic purpura (TTP) was considered, but ADAMTS13 activity was 35%. She was subsequently treated with eculizumab for suspected atypical hemolytic uremic syndrome (aHUS). Despite broad-spectrum antibiotics and eculizumab, she developed progressive, symmetric ischemic necrosis of her fingers and toes, leading to dry gangrene. Her clinical status declined, requiring a tracheostomy, and care was ultimately transitioned to comfort measures. Discussion This case demonstrates a rare and devastating manifestation of C. canimorsus sepsis. The patient developed a clinical picture consistent with a thrombotic microangiopathy, leading to treatment for aHUS, though the presentation was ultimately refractory to therapy. The development of symmetric peripheral gangrene (purpura fulminans) highlights the profound endotoxic and vascular complications of this organism. This case underscores the importance of considering C. canimorsus in patients with sepsis and pet exposure, even without traditional risk factors, and illustrates the diagnostic challenge of differentiating severe sepsis-induced TMA from primary aHUS. This abstract is funded by: None

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Cite This Study

Maryam et al. (Fri,) studied this question.

synapsesocial.com/papers/6a0d4f34f03e14405aa9a684 https://doi.org/https://doi.org/10.1093/ajrccm/aamag162.6152

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