Page 112 - June 2022

VETERINARY VIEWS
EQUINE MUSCLE DISORDERS:
EXERTIONAL RHABDOMYOLYSIS AND EQUINE POLYSACCHARIDE STORAGE MYOPATHY
by Nancy S. Loving, DVM
In most cases, a muscle disorder in an athletic horse arises from one of the following situations:
• Muscle strain
• Rhabdomyolysis
• Weakness and exercise intolerance
• Abnormal muscle contraction and
nerve conduction
• Muscle atrophy
Identifying the exact nature of a horse’s muscle problem depends on characterizing the symptoms to narrow down the problem. In addition to careful, physical inspection of a horse’s muscle mass and symmetry, hands-on palpation provides information about muscle tone and a horse’s comfort level or pain. Motion evaluation of the horse is also telling along with a full lameness exam.
Typical clinical signs of muscle problems include muscle stiffness, altered muscle tone,
© Getty Images
© Getty Images
110 SPEEDHORSE June 2022
Hands-on palpation provides information about muscle tone and a horse’s comfort level or pain and helps identify muscle problems.
muscle cramping, acute onset hind limb lameness, refusal to move, and other signs of distress such as increased heart and/or respiratory rates, sweating, and/or colic symptoms.
EXERTIONAL RHABDOMYOLYSIS (ER)
Skeletal muscle disease has long been associated with exercise and is referred to by many names: Azoturia, Monday morning
In the initial days following an ER episode, a horse should be confined to a stall with
minimal hand walking. Once stiffness dissipates, the horse may be turned out into a small paddock with monitoring of muscle enzymes until their values return to normal.