Miniature Dachshund puppy Margot who devoured a tube of Dovonex ointment and gave herself potentially fatal vitamin D toxicity has made a full recovery, thanks to the internal medicine team at leading veterinary referral practice Davies Veterinary Specialists (Davies), based near Hitchin, Hertfordshire.
Dovonex ointment, which is prescribed to humans to treat psoriasis, contains calcipotriol, a synthetic vitamin D3 analogue.
“We calculated that four-month-old Margot had ingested between 500-1000µg (161µg/kg – 323µg/kg) of calcipotriol,” said Katherine Clarke who is an Internal Medicine resident at Linnaeus-owned Davies. “Toxicity studies in dogs suggest that 1.8 to 3.6µg /kg /day of calcipotriol can cause disturbances in calcium homeostasis, so it wasn’t surprising that Margot developed evidence of toxicity.”
On presentation Margot was severely hypercalcaemic and mildly azotaemic. She was also nauseous, lethargic and depressed. She was hospitalised and her vitamin D toxicity was initially managed with prednisolone, furosemide and intravenous fluid therapy (using Plasma-Lyte). Although she improved clinically, the hypercalcaemia persisted, prompting the addition of pamidronate to her treatment. This combination resulted in normocalcaemia and resolution of the azotaemia. The furosemide was then stopped, and the intravenous fluid therapy was gradually reduced over a few days; her calcium remained normal.
Margot was discharged on tapering doses of prednisolone and blood tests were performed prior to each dose reduction to ensure she remained normocalcaemic. She has now been off all treatment for a couple of months, is clinically very well and there does not appear to be any permanent damage caused by the vitamin D toxicity.
“Vitamin D toxicity is relatively rare, although the growing trend in vitamin D supplementation in the human population means that dogs are more likely to have access to this vitamin,” said Katherine.
“Ingestion of psoriasis cream, either by licking it from the skin of the owner or direct ingestion by chewing the tube, is another well recognised mechanism of vitamin D toxicity in dogs,” she continued. “The addition of vitamin D (cholecalciferol) to rodenticides is also increasing, ingestion of which would cause the undesirable combination of vitamin D toxicosis and a coagulopathy”.
“The prognosis for vitamin D toxicity is variable with some cases experiencing an acute kidney injury or severe gastrointestinal bleeding due to calcification of the soft tissues. However, with prompt, aggressive treatment the prognosis can be reasonable.”
To find out more about Davies visit www.vetspecialists.co.uk