Friday, January 2, 2009

Happy New Year!

Everyone loves a clean slate and we hope 2009 is just that for in small animal land we're taking some time out to plan the next twelve months or so, resolving to read more, take more photos of interesting cases (instead of having a mental debate and missing the moment) and spend a bit more time chillaxing.

Meanwhile given we're in tick season (a bit of a misnomer these days since we're seeing more ticks in the traditionally "tick-free" months of the year) I wanted to share an interesting case with you. A young Border collie pup who presented to me with a history of vomiting and profound depression and bradycardia (a slow heart rate - it was sitting at around 40-60 beats per minute when a dog her age and size should be around 120-160). She could hardly move. To all intents and purposes she looked like a dog suffering from tick paralysis. The night before her loving family had decided to prevent tick envenomation - washing her with an anti-tick shampoo then adding an anti-tick collar just to be sure. Well, being the age she was she ate part of her collar. The active ingredient in the collar, amitraz, prevents ticks...but being an alpha-2 agonist, it has sedative properties when eaten. Vets use alpha-2s to induce sedation or as part of an anaesthetic protocol in animals. These days they're used more in zoo and large animal medicine, but have been larely superseded in small animal medicine. Fortunately though, because vets have the need to reverse sedation, the drugs used to reverse these agents can also reverse side effects of amitraz ingestion - as I discovered when I spoke to Dr Mark Kelman, technical services vet for the manufacturer of the collar.

The full case report, together with a discussion on the pharmacokinetics of amitraz, is written up in the latest issue of the Australian Veterinary Practitioner. The good news is that after a few days hospitalisation, during which I painstakingly waited for the dog to poo out the ingested remnants of collar, the patient made a full recovery and her loving family bought her back in the next week to show us how bright and happy she was.

Fawcett AF and Kelman M (2008) Amitraz toxicity in a dog following ingestion of amitraz-impregnated collar. Australian Veterinary Practitioner 38(4):142-145.