Vestibular and auditory dysfunction Flashcards
How does mentation vary based on whether a vestibular lesion is central or peripheral?
Central - depressed, stupor, obtunded, comatose
Peripheral - normal or slightly disorientated
Head tilts are common in unilateral vestibular dysfunction. Are they towards or away from the lesion?
Towards
except paradoxical vestibular dysfunction
Nystagmus can be jerk or spontaneous. If nystagmus is vertical, where is the lesion?
Central vestibular system
With peripheral and central vestibular disease, is the nystagmus fast phase towards or away from the lesion?
Peripheral - away
Central - either
Give examples of what may cause bilateral vestibular dysfunction, with loss of balance to both sides and no postural symmetry
Thiamine deficiency
Metronidazole toxicity
Bilateral otitis media/interna
Ischaemia of the brain is more common than haemorrhage. Give examples of common underlying systemic conditions that may cause cerebrovascular accidents
Hypertension PLE/PLN Cushing's Thyroid pathology Endocarditis Neoplasia
Which infarction is associated with vestibular signs?
Cerebellar infarction
Seen with decerebellate rigidity, ataxia +/- hypermetria
Deafness can be congenital sensorineural. Give examples of what animals this may be seen in
White pigmentation and blue eyes
Piebald/Merle genes
(NOT related to albinism)
Give examples of what may cause acquired deafness
Presbycusis (old age) Chronic otitis Ototoxicity Noise trauma Anaesthesia related
What are the 2 main diagnostic tests for testing hearing function?
Brainstem auditory evoked response (BAER - more expensive, more reliable) Otoacoustic emissions (OAE - less expensive, less reliable)
Idiopathic vestibular dysfunction is seen in what age dogs?
Older
AKA geriatric vestibular syndrome
What is the treatment for idiopathic vestibular dysfunction (or geriatric vestibular syndrome)? What is the prognosis?
None - self resolving
(NO STEROIDS!)
Prognosis good but head tilt may be permanent
Metronidazole toxicity may be seen in cats and dogs with a history of high doses of metronidazole. How is this treated?
Diazepam
Symptomatic therapy
(Prognosis good-excellent)
What causes otogenic abscessation?
Ascending infection (otitis media/interna) via vestibulocochlear nerve (CNVIII)
With paradoxical vestibular dysfunction, are head tilts and fast phase of nystagmus towards or away from the lesion?
Nystagmus fast phase towards lesion
Head tilt away
