Page 873 - Problem-Based Feline Medicine

39 – THE CAT WITH TREMOR OR TWITCHING 865

Diagnosis HYPOKALEMIA

Cerebrospinal fluid may contain increased numbers
of nucleated cells and/or elevated protein concentra- Classical signs
tions.
● A short duration tremor may be present
Nucleated cell counts can vary from mildly inflamma- episodically and usually when the cat
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tory (0.005–0.020 × 10 cells/L [5–20 cells/μl]; normal attempts purposeful movement.
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< 0.002–0.005 × 10 cells/L [2–5 cells/μl]) to greatly ● Aged cats or Burmese < 1 year.
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inflammatory (> 0.05 × 10 cells/L [50 cells/μl]). ● Ventral neck flexion.
● Stiff, stilted gait.
The nucleated cell type is variable, but most often is
● Reluctance to walk or jump, and physical
a mononuclear cell population. Neutrophils may also
inactivity.
be seen.
● +/- Sensitivity to palpation of larger
In cats with FIP, CSF protein concentrations are usually muscle groups.
elevated at greater than 2 g/L (200 mg/dl), and nucle-
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ated cell counts are greater than 0.1 × 10 cells/L (100 See main reference on page 893 for details (The Cat
cells/μl). With Neck Ventroflexion) and on page 945 (The
Cat With Generalized Weakness).
In cats with FIP the predominant nucleated cell type
present in the CSF is neutrophils
Clinical signs
In cats with encephalitis from other suspected viral eti-
ologies, CSF protein concentrations are usually less Signalment is typically aged cats > 8 years or young
than 1 g/L (100 mg/dl), and nucleated cell counts are Burmese < 1 year (usually 2–6 months).
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less than 0.05 × 10 cells/L (50 cells/μl).
Typically there is a history of acute onset of weakness.
Advanced imaging studies (CT or MR) may show However, decreased activity and inappetence are
multifocal lesions. Often these lesions are enhanced often present for weeks to months prior to presenta-
by intravenous contrast administration. tion.

A short-duration tremor may be present episodically
Differential diagnosis and usually when the cat attempts purposeful move-
ment
Rule out other inflammatory, metabolic, and degenera-
tive causes of tremor. Clinical signs include ventral neck flexion, stiff,
stilted gait, and a reluctance to walk or jump.
Physiological functions such as shivering from cold or
Typically, weak cats do not walk far, but soon sit or lie,
apprehension should be considered.
flopping down, instead of carefully sitting as normal
cats do. Sensitivity to palpation of larger muscle groups
Treatment may be noticed.
Treatment with corticosteroids (prednisolone 2 mg/kg Dyspnea occurs when the potassium is very low
q 12 h initially) may improve clinical signs. (2.0–2.5 mmol/L), because of weakness of the respira-
tory muscles. It may occur after fluid administration
If clinical signs improve, the corticosteroid therapy
because volume dilution and increased urinary potas-
should be slowly tapered (over months) to prevent
sium loss induced by diuresis may lead to further wors-
recurrence.
ening of the hypokalemia.
Young Burmese cats are susceptible to this disease,
Prognosis
and potassium depletion may have played a role in the
Clinical response to corticosteroid is variable. previously described myopathy of Burmese cats.