Effects of 6 Weeks of Parenteral Cobalamin Supplementation on Clinical and Biochemical Variables in Cats with Gastrointestinal Disease

BACKGROUND Effects and duration of commonly used protocols for cobalamin (Cbl) supplementation on cellular Cbl deficiency have not been determined in hypocobalaminemic cats. HYPOTHESIS/OBJECTIVES To evaluate effect of Cbl supplementation on clinical signs, serum and urine methylmalonic acid (MMA) concentrations over 16 weeks. ANIMALS Twenty client-owned hypocobalaminemic cats with enteropathy. METHODS Prospective study. Serum Cbl and serum and urine MMA concentrations were determined prospectively in cats at enrollment (t0), immediately before (t6), and 4 (t10) and 10 weeks (t16) after 6th Cbl injection (250 μg, IM q 7 days). Clinical signs severity (activity, appetite, vomiting, diarrhea, body weight) graded at each time point and expressed as clinical disease activity score. RESULTS Clinical disease activity score decreased during supplementation and increased after treatment discontinuation. Median serum Cbl concentration increased significantly from t0 (111 pmol/L, range 111-212) to t6 (2,332.5 pmol/L, range 123-22,730) (P < 0.01). Values at t10 were 610.5 pmol/L (range, 111-2,527) and 180.5 pmol/L (range, 111-2,262) at t16 (P < 0.01). Median baseline serum MMA concentration (372 μmol/L, range 0.39-147,000) decreased significantly to 1.62 μmol/L (range, 0.18-806) at t6 (P < 0.01) and gradually increased to 5.34 μmol/L (range, 0.13-1,730) at t10 and 189 μmol/L (range, 0.4-983) at t16. Similar, nonsignificant, pattern observed for urine MMA concentration. Serum and urine MMA concentrations had not normalized in 12 and 6 cats, respectively, at t6. CONCLUSION AND CLINICAL IMPORTANCE The Cbl supplementation protocol used here did not lead to complete normalization of cellular Cbl deficiency in all examined cats, and biochemical improvements were transient.