EXPRESS: Presumed vitamin K-dependent coagulopathy secondary to low grade alimentary lymphoma in a cat

Case summary: A 10-year-old, male castrated domestic shorthair cat was evaluated for a one-year history of progressive small bowel diarrhea, vomiting and significant weight loss despite a good appetite. Diagnostic evaluation included an upper gastrointestinal endoscopy, after which the cat developed severe anemia due to gastrointestinal hemorrhage. Coagulation testing revealed prolonged prothrombin time and partial thromboplastin time with decreased factor VII activity. The cat had no access to the outdoors, and no rodenticide was kept in the home. Disseminated intravascular coagulopathy and liver dysfunction were ruled out. Endoscopic biopsies were consistent with low-grade alimentary lymphoma. This, in combination with clinical support for malabsorptive disease, suggested vitamin K malabsorption as the underlying cause for the cat’s coagulopathy. Despite aggressive critical care with vitamin K supplementation and packed red cell and plasma transfusions, the cat developed complications and ultimately humane euthanasia was elected. Relevance and novel information: This case highlights suspected malabsorptive vitamin K-deficient coagulopathy secondary to chronic GI disease in a cat. Coagulopathy screening or pre-treatment with vitamin K may be warranted prior to endoscopic gastrointestinal biopsies in these cases.