Differential Diagnoses of Equine Myopathies
Myopathy Type | Differential Diagnoses |
|---|---|
Non-exercise-associated Rhabdomyolysis | |
Inflammatory | Influenza myositis Immune-mediated myositis |
Toxic | Ionophore toxicity Senna occidentalis Rayless goldenrod/white snakeroot Hypoglycin A in box elder and European sycamore trees |
Traumatic | Compressive anesthetic myopathy Trauma |
Genetic | Glycogen branching enzyme deficiency in Quarter Horse foals Polysaccharide storage myopathy types 1 and 2 Malignant hyperthermia in Quarter Horses Myosin heavy chain myopathy (Quarter Horse-related breeds) |
Exertional Rhabdomyolysis | |
Focal muscle strain Overexertion, dietary imbalances, vitamins, minerals, electrolytes | |
Polysaccharide storage myopathy types 1 and 2 Recurrent exertional rhabdomyolysis Idiopathic chronic exertional rhabdomyolysis | |
Exertional Myopathy with Normal CK activity | |
Polysaccharide storage myopathy type 2 Myofibrillar myopathy | |
Muscle Atrophy | |
Myogenic atrophy | Severe rhabdomyolysis Disuse Immune-mediated myositis (rapid atrophy) Vitamin E–responsive myopathy Homozygous polysaccharide storage myopathy type 1 Myofibrillar myopathy |
Neurogenic atrophy | Equine protozoal myelitis Local nerve trauma Idiopathic peripheral neuropathy Toxic peripheral neuropathies |
Muscle Fasciculations | |
Pain, fear Weakness (botulism, chronic debilitation) Electrolyte abnormalities Hyperkalemic periodic paralysis Hypokalemia Otobius megnini (ear tick) infestation Stiff horse syndrome |