Thiamine deficiency

From Dog

Thiamine is an essential vitamin (B1).

Thiamine deficiency is relatively rare in dogs and is usually caused by feeding sulphite-treated fresh meat, which catalyses thiamine in the feed[1].

This condition is usually a dietary-induced disease, although it has been reported following use of amprolium for treatment of intestinal parasites[2] and lead toxicity and can affect dogs of any age, with thiamine deficiency resulting in malacia of multiple brainstem nuclei and oedema of the cerebral cortex.

Amprolium is an analog of thiamine that acts via competitive inhibition and can cause signs of thiamine deficiency in dogs[3].

Clinically affected patients present with a history of inappetence, weight loss and vomiting that rapidly progresses to signs of multifocal intracranial disease including mental dullness, paresis, seizures, spontaneous nystagmus and strabismus.

Diagnosis is based on blood thiamine levels and postmortem confirmation of caudate nuclei malacia and cerebral edema.

A differential diagnosis would include Leigh syndrome (necrotizing encephalomyelopathy)[4].

Treatment usually requires thiamine supplementation, both parenterally and dietary, given at 25 – 50 mg/day parenterally or orally.


  1. Singh M et al (2005) Thiamine deficiency in dogs due to the feeding of sulphite preserved meat. Aust Vet J 83(7):412-417
  2. Hazlett MJ et al (2005) A degenerative encephalomyelopathy in 7 Kuvasz puppies. Can Vet J 46(5):429-432
  3. Plumb DC (2002) Appendices. In: Plumb DC ed. Veterinary Drug Handbook, 4th pocket ed. Iowa State Univ Pr. pp:806–807
  4. Brenner O et al (2000) Alaskan husky encephalopathy — a canine neurodegenerative disorder resembling subacute necrotizing encephalomyelopathy (Leigh syndrome). Acta Neuropathol 100:50–62