Border collie case study: hereditary selective cobalamin malabsorption

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1 Vet Times The website for the veterinary profession Border collie case study: hereditary selective cobalamin malabsorption Author : ELUNED SALISBURY Categories : Vets Date : August 25, 2008 ELUNED SALISBURY describes her own dog s experience of this condition, and urges practitioners to consider it as a diagnosis for certain breeds that present in a deteriorated state with a poor appetite AS we leave the farmyard after a protracted large animal visit, how many of us veterinary surgeons in mixed practice have given a quick shot of the pink stuff to a sheepdog that is reportedly a bit off colour and not eating brilliantly? How many of us were surprised - at least initially - to hear that the dog has subsequently never looked back? It s comforting and interesting to know that there may actually be a sound scientific basis for the reason that vitamin B 12 seems to have a miraculous effect on many unthrifty border collies. For this reason, I d like to share Elsi s story - my own dog s experience of selective cobalamin malabsorption. Inappetence and enteritis I took possession of Elsi when she was eight weeks old. She was a happy, healthy and welladjusted puppy with a good appetite. She was quick to learn, grew well and was enjoying life to the full, until she was seven months old. At this time, she began to look unthrifty and, for the next two months, she failed to grow or gain any weight. 1 / 6

2 Her appetite had deteriorated progressively since she was about five months old, but from the age of seven months, her poor appetite began to be an issue, despite the fact that she was otherwise fit and happy. Her appetite had deteriorated progressively since she was about five months old, but from the age of seven months, her poor appetite began to be an issue, despite the fact that she was otherwise fit and happy. She went on to develop a severe enteritis (as did many dogs in our area), but Elsi s condition was completely unresponsive to treatment. A full blood profile and a canine-specific lipase test suggested that she had acute pancreatitis, which we considered odd in such a young dog. Within a fortnight, her condition deteriorated so much that we began to suspect an abdominal catastrophe, and one of my colleagues performed an exploratory coeliotomy. No gross pathology was detected, so we kept Elsi hospitalised and administered treatment for acute pancreatitis. Deterioration and hospitalisation Five days later, following no signs of improvement, the dog deteriorated further. She looked anaemic and she was very weak and hypokalaemic, so I referred her as an emergency to the University of Liverpool small animal teaching hospital. The abnormalities detected by routine biochemistry tests, which were performed on admission, are described in. Intravenous fluids with Hartmann s solution and colloids were administered, together with supportive treatment. Further diagnostic tests were performed over the next few days. These showed that Elsi had mild anaemia and neutropaenia. However, her ACTH stimulation test, canine pancreatic lipase immunoreactivity, radiography, ultrasonography, urinalysis/ culture and sensitivity, and faecal analysis were all normal. Her serum folate was low (6.7µg/L - reference range µg/L), but the most striking result was an immeasurably low serum cobalamin concentration (100.Ong/L - reference range Ong/L). Cyanocobalamin therapy and resolution As a result, parenteral cyanocobalamin therapy (vitamin B 12 at 20µg/kg) was given. After this, 2 / 6

3 Elsi s diarrhoea resolved and she showed a remarkable improvement in her overall demeanour, and her appetite improved overnight. Ever since that day, she has enthusiastically eaten everything and anything offered to her. Evaluation In this case, it was initially unclear whether the low serum cobalamin was the primary problem - causing a secondary enteropathy - or whether the enteropathy was causing malabsorption of cobalamin from the distal small intestine. Given that border collies are predisposed to a hereditary selective cobalamin malabsorption, and given the dramatic improvement after starting cyanocobalamin supplementation, the former possibility seemed more likely. A urine sample was submitted for methylmalonic acid (MMA) measurement - a metabolic precursor that is elevated in cobalamin deficiency - to the Metabolic Screening Laboratory at the University of Pennsylvania, which confirmed the likelihood of cobalamin malabsorption. Consequently, Elsi was discharged from Liverpool within 48 hours of her first vitamin B12 injection, and regular cobalamin supplementation has been continued ever since. Her latest level was 418ng/L, so we have reduced the frequency of her injections from weekly to fortnightly. Hereditary selective cobalamin malabsorption in dogs has previously been described in giant schnauzers, beagles, border collies and Australian sheep dogs in the USA, but it remains a littleknown abnormality in the UK (Fyfe et al, 1989, 1991; Outerbridge et al, 1996; Fordyce et al, 2000; Fyfe, 2000; and Cullen, Fyfe and Giger - unpublished observations). Frustratingly, a genetic screening test for the condition has not yet been developed, but research is ongoing. As a practising vet, who almost gave up on her own beloved pup, I am hoping that practitioners will consider the possibility of selective cobalamin malabsorption in any juvenile border collie that is failing to thrive and presents with a poor appetite. The diagnostic test for this condition is simple, and response to treatment is rapid, cheap and fantastically rewarding. Acknowledgements The author extends her sincere and grateful thanks to Alex German (Waltham senior lecturer in small animal medicine) and Thomas Ingman Roberts (then a final-year veterinary student) - of the department of veterinary clinical sciences at the University of Liverpool s small animal teaching 3 / 6

4 hospital - for the professionalism and care with which they handled Elsi s case, and for their help with this article. Elsi (pictured) was a healthy puppy until the age of seven months, when she appeared unthrifty and, for the next two months, failed to grow or gain weight. Tests revealed an 4 / 6

5 immeasurably low serum cobalamin concentration. Parenteral cyanocobalamin therapy proved to be successful. 5 / 6

6 Powered by TCPDF ( Elsi (pictured) was a healthy puppy until the age of seven months, when she appeared unthrifty and, for the next two months, failed to grow or gain weight. Tests revealed an immeasurably low serum cobalamin concentration. Parenteral cyanocobalamin therapy proved to be successful. TABLE 1. Routine biochemistry results 6 / 6