Case description: A 2.5-year-old 12.4-kg (27.3-lb) castrated male Scottish Terrier was evaluated because of episodes of hypertonia and kyphosis for which a presumptive diagnosis of so-called Scottie cramp had been made when the dog was a puppy.
Clinical findings: Findings of general physical, orthopedic, and neurologic examinations were within reference limits. Pelvic limb hypertonicity and kyphosis without signs of pain were induced with minimal exercise; ambulation returned to normal after a period of rest.
Treatment and outcome: Fluoxetine, a selective serotonin reuptake inhibitor, was administered orally at a dosage of 1.2 mg/kg (0.55 mg/lb) once daily for 1 month. After this period of treatment, clinical signs of the disease were greatly reduced; the dosage of fluoxetine was changed to 0.8 mg/kg (0.36 mg/lb) twice daily, and response to treatment continued.
Clinical relevance: 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. It has been suggested that the pathogenesis of this disease is related to deficiencies in concentration or function of serotonin in the CNS; thus, a logical choice for treatment is administration of a serotonin reuptake inhibitor. In the dog of this report, fluoxetine resulted in good control of clinical signs. The use of an effective medication (other than a controlled substance) that is administered once or twice daily, has minimal adverse effects on the patient's mental status, and is inexpensive may lead to better owner compliance and an improved quality of life for affected dogs.