Cobalamin concentrations were previously investigated in cats, but little information is available concerning the follow up of hypocobalaminemic cats. We aimed to assess the frequency of hypocobalaminemia within a large cohort of cats with gastrointestinal signs and describe the epidemiological, clinical, biological and follow-up characteristics of hypocobalaminemic cats.
1495 cats with gastrointestinal signs and for which a cobalamin assay (SimulTRAC-SNB radioassay kit VitaminB12®, MPBiomedical) was performed between 2007 and 2014 at the LDHVet laboratory were retrospectively included in the study.
259 (17.3%) cats presented for gastrointestinal signs had an hypocobalaminemia: the majority were Domestic Short Hair, 47% were males (84% castrated) and 53% females (94% castrated), aged from 3 months to 18 years. The main clinical signs included chronic diarrhea (93%), weight loss (71%), polyuropolydypsia (48%), vomiting (43%), polyphagia (38%), fatigability (36%) and dysorexia (19%) with a median duration of 4 months before diagnosis. Cobalamin values ranged from 44 to 400 ng/L (median: 296 ng/L). 60% of the hypocobalaminemic cats had also a hyperfolatemia (folate > 12 ng/L) at diagnosis. fT4 was measured in the 64 older cats (> 12 yrs) and revealed an hyperthyroidism (fT4 > 40 pmol/L) in 20% of the cases. 67/259 hypocobalaminemic cats had a known clinical and biological follow-up (median time follow-up = 44 days): cobalamin significantly improved one month after treatment (50µg/kg IM cyanocobalamin in a single dose) for 87% of the cats, even if 16% remained hypocobalaminemic. 62% of the followed cats were clinically improved, of which 85% with an associated higher cobalamin value. Clinical and biological improvement after cobalamin supplementation was significantly associated with an increase in folate concentration (p-value = 0.02).
However, 33% of the cats with an improved cobalamin value did not show any clinical improvement.
Hypocobalaminemia is frequently observed in cats as a consequence of gastrointestinal signs. Cobalamin concentrations could be used as an indicator of the severity of various gut diseases more than a primary cause, because one third of the cats did not show any clinical improvement despite an improved cobalamin value. A hyperfolatemia appearing after treatment of hypocobalaminemia seems to be a good indicator of a clinical improvement associated with a return to a normal intestinal integrity.