In clinically affected dogs, ataxia usually presents as pelvic limb hypertonicity and kyphosis without signs of pain and can be induced with minimal exercise. Normal ambulation is restored following a period of rest. Symptoms usually worsens with age but rarely become life threatening.
The disorder appears to be due to a deficiency in concentrations or function of serotonin in the CNS and decreasing CNS concentrations of serotonin via para-chlorophenylalanine (pCPA) will profoundly increase the severity of the disease although the basic defect does not involve serotonergic neurons.
Definitive diagnosis can be established by muscle biopsies and trial injections of methysergide, where symptoms markedly worsen.
Administration of benzodiazepines, vitamin E, or phenothiazines has been recommended for treatment of episodes of hypertonicity, but often does not result in control of clinical signs.
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