Page 847 - Problem-Based Feline Medicine

38 – THE CAT WITH A HEAD TILT, VESTIBULAR ATAXIA OR NYSTAGMUS 839

severity of the inflammation. Although inflamma-
DISEASES CAUSING A HEAD TILT,
tory diseases are multifocal or diffuse pathologi-
VESTIBULAR ATAXIA OR
cally, this is often not the case clinically, where the
NYSTAGMUS
neurological deficits in most cases can be assigned
to one location.
IDIOPATHICVESTIBULAR SYNDROME***
Diagnosis is based on careful history taking (to dis-
close if there is somnolence or quietness of the ani-
Classical signs
mal), physical, neurological, otoscopic and
ophthalmoscopic (including Schirmer tear test) ● Acute to subacute onset of a head tilt,
examinations, serum protein concentration, cere- falling, rolling and nystagmus.
brospinal fluid analysis (CSF), CSF anti-coronavirus ● Disorientation can be severe with the cat
IgG titer, electrodiagnostic testing (brain auditory- unwilling to move and crying out with
evoked responses), bullae radiography, computed anxiety.
tomography (CT) and magnetic resonance imaging ● Otherwise healthy cat.
(MRI) scan.
Reference ranges for feline CSF. Pathogenesis
9
● RBC < 0.030 × 10 /L (30/μl)
9
● WBC ≤ 0.002 × 10 /L (2/μl) Unknown.
● Cytology (%)
Clinical signs
– Monocytoid cells 69–100%
– Lymphocytes 0–27% Possibly higher incidence in July and August in north-
– Neutrophils 0–9% east United States.
– Eosinophils 0
– Macrophages (large foamy mononuclear cells) Cats of any age or sex, median age is 4 years old.
0–3% Acute, non-progressive, unilateral and occasionally
● Protein 0.036 g/L (36 mg/dl) bilateral, peripheral vestibular disturbance.

It is good practice to request electrodiagnostic testing The head tilt, ataxia and nystagmus (most often hori-
(BAER) to evaluate for deafness. If deafness is con- zontal) can be severe with the animal crying out with
comitantly present, it is an indication of a more aggres- anxiety, reluctant to walk, remaining in a crouched pos-
sive disorder and a thorough diagnostic work up should ture or with wide abduction of the limbs.
be pursued.
Rarely, can be bilateral.
When a head tilt is present, or when there is facial
Vomiting occasionally occurs, usually soon after onset
paresis/paralysis or a Horner’s syndrome, bulla radi-
of signs.
ography is recommended to evaluate the middle
ear cavities. An open mouth view is best to compare Affected cats are otherwise healthy.
the density between the bullae. Bulla radiography is
not a sensitive tool. It may be normal despite the pres- Diagnosis
ence of disease. Computed tomography (CT) scan of
History of an acute to subacute onset, in a previously
the bullae is superior and should be done when avail-
healthy cat, of severe disorientation, falling and rolling,
able.
that improves rapidly (a few days to 2 weeks) and with-
Regardless of the cause of the vestibular signs, nystag- out treatment.
mus and vestibular ataxia usually resolve, but the head
The cat is otherwise healthy and has no other neurolog-
tilt usually persists for the life of the animal. It may
ical signs.
be barely noticeable but may be exacerbated after
a general anesthetic or when the cat is ill. The otoscopic examination is unremarkable.