Clinical characteristics of Scottie Cramp in 31 cases.

OBJECTIVE: To report the clinical features, with response to therapy and long-term outcome of Scottie Cramp as described by owners. METHODS: Owners of affected dogs provided a description of clinical signs, age of onset and disease progression. Medical records, pedigrees and videotapes of cramp episodes were evaluated. RESULTS: Thirty-one dogs were recruited; 19 showed generalised spasticity and 12 exhibited only hind limb spasticity and skipping. Episodes were noted in the first year of life in 76% of dogs and were triggered by excitement, stress and exercise. Episode frequency and severity decreased over time with behaviour modification and decreased exposure to triggers playing a role in their development. One dog was euthanased because of severe refractory signs. Fluoxetine reduced the frequency and duration of episodes in seven dogs, but not in one severely affected dog. Female dogs were over-represented with only eight affected males in the study cohort, and the presence of dogs with cerebellar degeneration in the same pedigrees may suggest a more complex mode of inheritance than previously reported. CLINICAL SIGNIFICANCE: The disorder recognised as Scottie Cramp by dog owners includes dogs with hind limb spasticity in addition to generalised cramping. Signs usually improve over time without specific treatment.

A canine BCAN microdeletion associated with episodic falling syndrome.

Episodic falling syndrome (EFS) is a canine paroxysmal hypertonicity disorder found in Cavalier King Charles spaniels. Episodes are triggered by exercise, stress or excitement and characterized by progressive hypertonicity throughout the thoracic and pelvic limbs, resulting in a characteristic 'deer-stalking' position and/or collapse. We used a genome-wide association strategy to map the EFS locus to a 3.48 Mb critical interval on canine chromosome 7. By prioritizing candidate genes on the basis of biological plausibility, we found that a 15.7 kb deletion in BCAN, encoding the brain-specific extracellular matrix proteoglycan brevican, is associated with EFS. This represents a compelling causal mutation for EFS, since brevican has an essential role in the formation of perineuronal nets governing synapse stability and nerve conduction velocity. Mapping of the deletion breakpoint enabled the development of Multiplex PCR and Multiplex Ligation-dependent Probe Amplification (MLPA) genotyping tests that can accurately distinguish normal, carrier and affected animals. Wider testing of a larger population of CKCS dogs without a history of EFS from the USA revealed that carriers are extremely common (12.9%). The development of molecular genetic tests for the EFS microdeletion will allow the implementation of directed breeding programs aimed at minimizing the number of animals with EFS and enable confirmatory diagnosis and pharmacotherapy of affected dogs.

Use of a selective serotonin reuptake inhibitor for treatment of episodes of hypertonia and kyphosis in a young adult Scottish Terrier.

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.

Newborn endothelin receptor type B mutant (piebald) mice have a higher resting anal sphincter pressure than newborn C57BL/6 mice.

Hirschsprung's disease is characterized by aganglionosis of the distal colon and hypertonicity of the anal sphincter. Endothelin receptor type B mutant (piebald) mice phenotypically resemble infants with Hirschsprung's disease in that these mice are susceptible to developing toxic megacolon because of the absence of ganglion cells in their distal colon. Therefore, we hypothesized that newborn piebald mice would have a higher resting anal sphincter pressure than would newborn wild-type mice. To test this hypothesis, we developed a reliable and reproducible technique for measuring the resting anal sphincter pressure in mice. Heterozygote breeding pairs of endothelin receptor type B mutant mice were purchased and bred in our animal facility. Pregnant, time-dated C57BL/6J mice provided control newborn mice. One-day-old newborn mice were evaluated for resting anal sphincter pressure. Under the operating microscope, a 24-gauge open-tip epidural catheter was placed into the anus until a deflection (approximately 3 to 5 mm) was noticed on a polygraph pressure monitor. Three consecutive measurements were obtained for each mouse. Mean values for each group were determined and compared using Student's t test. The resting anal sphincter pressure (mean +/- standard deviation) in newborn C57BL/6J mice was 13.3 +/- 2.6 mmHg, whereas that in piebald mice 22.7 +/- 2.5 mmHg (P < 0.0001). Therefore, because of their increased resting anal sphincter pressure, piebald mice may provide a useful animal model for the study of Hirschsprung's disease.

Acute polymyopathy after carbamate poisoning in a dog.

The acute polymyopathy in a seven-year-old German shepherd dog was attributed to the muscular hypertonia, tremors and seizures which developed during the acute phase of carbamate poisoning. After two days of generalised muscular rigidity, the dog adopted a characteristic fetal position which could be explained by the imbalance between the injuries to the extensor and flexor muscles. The polymyopathy resolved gradually over the course of a week.

Vertebral fracture, extensor hypertonia of thoracic limbs, and paralysis of pelvic limbs (Schiff-Sherrington syndrome) in an Arabian foal.

An Arabian foal, which was recumbent for 4 days, had signs of extensor rigidity of the thoracic limbs and hypotonic paralysis of the pelvic limbs. Survey radiography revealed a lesion at T15, with radiographic impression of a compression fracture or a hemivertebra. Postmortem examination revealed a fracture at T15. Clinical and pathologic findings in this case were compatible with the Schiff-Sherrington syndrome, which is characterized by thoracic limb extensor hypertonia associated with paraplegia from acute thoracolumbar trauma.