Dr. Byers welcomes critical care questions from veterinarians and veterinary technicians.
Click here to submit your question, or send an e-mail to email@example.com
with the subject line "Critical care questions."
Alice, my patient and my own dog, has acutely and progressively gone blind over the past two weeks. She is a 13-year-old spayed
female Staffordshire terrier. Her vaccination status is current, she is receiving internal and external parasite preventives,
and she has had no exposure to toxins. She has not had any polyuria or polydipsia but has become noticeably polyphagic. She
seems disoriented, and some movements are what I would call jerky or sudden. Her gait and the rest of her initial neurologic
examination findings were normal. Her complete blood count, serum chemistry profile, and urinalysis results were normal, as
were her pupil sizes and pupillary light reflexes. Could she have a tumor on her optic chiasm or another neurologic condition?
A. Alice's clinical signs are interesting and, unfortunately, not very clear-cut. If the primary issue is ultimately a visual
deficit with behavioral changes, perhaps the jerky movements are secondary to this deficit. However, these movement abnormalities
may certainly be secondary to something more sinister such as a cerebellar lesion or a prosencephalic lesion, and, thus, multifocal
disease must be considered.
Dr. Christopher G. Byers
I first recommend a blood pressure measurement and then a complete ophthalmic examination to rule out sudden acquired retinal
degeneration syndrome (SARDS), progressive retinal atrophy (PRA), and a hypertensive retinopathy. This examination will also
allow evaluation for possible optic neuritis. If no abnormalities are documented on ophthalmic examination, evaluation by
a neurologist to follow with advanced imaging (particularly magnetic resonance imaging) and cerebrospinal fluid evaluation
are likely needed.