Case 32: Blind

Case 32 — Blind

Primary clinician: Brad Gavaghan, DVM, DACVIM (Cardiology)
Supervising clinician: Mark D. Kittleson, DVM, PhD, DACVIM (Cardiology)

Mickey is presented to the VMTH with a 2-month history of progressive vestibular dysfunction and loss of vision OU.
The owner first noticed him being clumsy when jumping on and off obstacles.
Four to six weeks ago, he became gradually more unstable on his front limbs and would bunny hop when attempting to climb stairs.
Three weeks ago the referring veterinarian noticed cataracts OU and he remarked that this cat came from a known litter of amyloid sufferers. Thoracic radiographs revealed slight cardiomegaly.
Mickey has mydriasis and limited vision OU.
A urinalysis showed +++ protein. T4 was normal at 1.4. Hematocrit was high at 48%. Albumin was mildly elevated at 3.95 g/dl, BUN was high at 39.5 mg/dl, and glucose was high at 224.4 mg/dl (possibly stress induced). Rest of blood work was unremarkable.
Today, Mickey is initially circling a lot, predominantly to the right; he loses his balance occasionally and falls to the right as well. He will also fall on his left side occasionally. He is very curious yet cautious, and he turns his head from side to side constantly.
Mickey eats baked chicken breast, chicken baby food, and Iams dry food. He is a finicky eater.

General: BARH, nervous, cautious. BCS: 5/9. T = 101.0°F; P = 244; R = 32.
Integument: NSF.
EENT: Eyes — mydriasis OU; poor to unresponsive pupillary light responses (PLRs) both direct and consensual bilaterally; mucoid discharge OU. Mouth — moderate dental calculus.
Musculoskeletal: Lean musculature, no atrophy.
Cardiovascular: No murmur ausculted at this point; a soft gallop rhythm was noted. Mucous membranes pink; CRT < 1 second; no edema; strong femoral pulses.
GI: NSF.
GU: Small soft bladder.
Lymph nodes: WNL.
Neurological Exam: Mentation — nervous, constantly pacing the room. Gait — insecure, moving head in wide excursions from side to side; holds head high when walking on the floor and low when carried on arm. Cranial Nerves — direct and consensual PLRs nearly non-existent OU; rest of cranial nerve exam normal. Postural Responses — tactile placing is present, while visual placing is absent. Hopping — slow but purposeful hopping. Spinal Reflexes — present. Muscle Tone — normal. Sensation/Pain — normal.

The blindness and decreased PLRs are consistent with a problem situated at the level of the retina, optic disc or optic nerve; however, brain disease must also be considered.
Rule outs include: (1) Extracranial abnormalities: metabolic, toxic or nutritional diseases; and (2) Intracranial causes: infectious/inflammatory disease; degenerative disease; vascular/ischemic incident; trauma; neoplasia.
Plan: Ophthalmology and cardiology consults today. Tomorrow we will perform an MRI and a CSF tap if consults and bloodwork are normal.