Background: Hypocobalaminemia is commonly seen as a surrogate marker for intestinal lesions and as a diagnostic guide for biopsy collection of the ileum. However, the correlation between serum cobalamin concentration and histopathologic lesions in the small intestine has not been investigated in cats.
Hypothesis/
Objectives: To determine the correlation between serum cobalamin concentration, histopathologic lesions, and outcome in cats with chronic enteropathy.
Animals: Formalin-fixed, paraffin-embedded duodenum and ileum samples from 73 cats with chronic enteropathy (CE).
Methods: Retrospective study. Tissue archives were systematically searched for cases of CE with serum cobalamin results. Samples were scored by a pathologist blinded to clinicopathological data using a modified World Small Animal Veterinary Association (WSAVA) scoring system. Outcomes were assessed using medical records and client questionnaires utilizing a modified Feline Chronic Enteropathy Activity Index (FCEAI) and 4-point outcome scale (0, worse; 1, unchanged, 2; improved; 3, remission)
Results: A total of 73 cases were identified and analyzed. Serum cobalamin concentrations were significantly negatively correlated with total WSAVA scores (P< 0.001) and cellular infiltrate scores (P< 0.001) but not with architectural scores. Out of 51 cases with hypocobalaminemia, 5 cases showed histopathologic lesions exclusively in the duodenum, while the ileum remained unaffected. Serum cobalamin concentration was not associated with the FCEAI or clinical outcome.
Conclusions and Clinical Importance: Serum cobalamin concentrations in cats with CE showed a significant negative correlation with histopathologic lesions, particularly cellular infiltration in the duodenum and the ileum. However, hypocobalaminemia may not always be indicative of ileal lesions in cats.
