Classification of Some Muscle Diseases

Classification of Muscle Diseases (Myopathies) in Horses

The primary signs that horses have often allow a muscle disease to be divided into 4 broad catagories;

1. Muscle damage (rhabdomyolysis)
   • Non-exertional rhabdomyolysis
     • Inflammatory causes
     • Nutritional causes
     • Toxic causes
       • Pasture myopathy (atypical myopathy)
     • Metabolic causes
   • Exertional rhabdomyolysis
     • Sporadic causes
     • Chronic causes
2. Muscle atrophy
   • Neurogenic causes
     • Equine Motor Neuron Disease
     • Equine Protozoa Myelitis
     • Focal Nerve Damage
   • Myogenic causes
     • Immune-mediated myopathy:
     • Chronic Disease
     • Malnutrition
     • Disuse
     • Cushings Disease
     • PSSM
3. Abnormal muscle twitching (fasciculations)
   • Myogenic origin
     • Myotonia
     • hyperkalaemic periodic paralysis (HYPP) 
     • Electrolyte imbalances
     • botulism
   • Neurogenic causes
     • Shivers
     • Myoclonus
     • Foacal nerve trauma
     • Ear ticks
4. Muscle weakness and exercise intolerance
   • Metabolic disorders

The focus of research in our laboratory is on causes of rhabdomyolysis and its treatment. Therefore more detailed information is provided on those topics on this website.