Abstract
Objectives: To describe a case of equine muscular dystrophy with myotonia. Methods: A 5-year-old horse presented with hypertrophy and delayed relaxation of the muscles of the hindlimbs from age 2 months. Testicular atrophy developed from 2 years of age. Action and percussion myotonia was associated with weakness in these muscles, and EMG showed diffuse myotonic discharges and myopathic features. Biopsy of the gluteal muscle showed adipose and connective tissue infiltration, marked variation in muscle fibre size, and moth-eaten, ring and whorled fibres. Results: Injection of apamin, a peptide blocker of calcium-activated potassium channels, which inhibits myotonia in human myotonic dystrophy, was ineffective in blocking myotonic discharges. Discharges promptly abated with 2% lidocaine injection. Conclusions: Myotonia in this horse is associated with dystrophic changes similar to human myotonic dystrophy, though there are some pharmacological differences.
Original language | English |
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Pages (from-to) | 294-299 |
Number of pages | 6 |
Journal | Clinical Neurophysiology |
Volume | 112 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2001 |
Keywords
- Apamin
- EMG in myotonia
- Equine
- Muscular dystrophy
- Myotonia
- Myotonic dystrophy
ASJC Scopus subject areas
- Clinical Neurology
- Radiology Nuclear Medicine and imaging
- Neurology
- Sensory Systems
- Physiology (medical)