A 6-month-old male sheltie is presented for head tilt and possible deafness. The clinical signs have been present since birth and are not progressive. The puppy has grown normally. There are two other littermates that may be affected.
Physical and Neurological Examinations
The puppy has a pronounced left head tilt but walks with minimal ataxia. The head swings in wide excursions to the left and right. There is no nystagmus or strabismus and conjugate eye movements cannot be elicited when the head is rotated left or right. The dog is visual, pupils are normal size in room light, and pupillary light reflexes are normal. Palpebral reflexes and menace responses are normal. Postural reactions and spinal reflexes are normal. The dog is not startled by loud noises and does not respond to auditory commands. Otoscopic examination is normal.
Identify the problems in this dog and write an initial plan for each complete with possible rule-outs.
Deafness is recognized by an animal’s failure to respond to auditory commands or to loud sounds. It is hard to detect in dogs and cats unless it is bilateral and nearly complete. Unilateral deafness is rarely recognized except in working dogs that have problems orienting to auditory commands or through electrodiagnostic testing.
Deafness is classified as central or peripheral and as congenital or acquired. To understand each classification, an understanding of normal hearing is necessary.