Just Ask the Expert: Differential diagnoses in a dog with a head tilt

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We saw a 5-year-old spayed female rat terrier mix 11 days ago for acute onset of imbalance and stumbling. No nystagmus or nausea or change in mentation had been noted. On examination, the dog was ataxic and had a head tilt down and to the right. Its left ear was held erect, as was normal for both of the dog's ears, but the right ear was held down. No nystagmus or spinal pain was noted. The dog appeared to have normal cranial nerve function, but we could not evaluate the ears or conscious proprioception reflexes. We initiated treatment with antibiotics, and there has been no change in clinical signs. What should be on our differential diagnosis list other than vestibular disease?

A. With the acute onset of signs that are nonprogressive in a 5-year-old dog, I think the most likely diagnosis is a brain infarction. You would need magnetic resonance imaging to confirm it, but given the patient's history and examination results, this would be a likely diagnosis.

Dr. David S. Bruyette

Often, we do not find an underlying cause for an infarction, but it would be a good idea to screen for hypothyroidism, check the urine for proteinuria, and obtain a blood pressure measurement to rule out hypertension.

David S. Bruyette, DVM, DACVIM

VCA West Los Angeles Animal Hospital

1818 S. Sepulveda Blvd.

West Los Angeles, CA 90025

Veterinary Diagnostic Investigation and Consultation

26205 Fairside Road

Malibu, CA 90256

SUGGESTED READING

1. Garosi L, McConnell JF, Platt SR, et al. Clinical and topographic magnetic resonance characteristics of suspected brain infarction in 40 dogs. J Vet Intern Med 2006;20(2):311-321.