On Monday, when put back in work, the horse shows signs of increasing muscle stiffness and pain. The syndrome also occurs in performance horses, whether used for racing, endurance, or English or Western events. Signs may occur when the horse is just warming up, is in the middle of a workout, or is being cooled down. Other signs of tying-up include increases in heart rate, respiratory rate, and temperature and may include sweating. The horse may move only with short, stilted strides or may be unable to move at all.
Renal failure is a possible resulting complication and cause of death.
A severely affected horse should not be walked because further exertion can lead to irreversible muscle damage. Therefore, Dr. Miller urges horse owners to call their veterinarian at the first signs of tying-up for diagnosis and treatment. Recovery is monitored by the decrease of these enzymes in the blood. When both fall to normal levels, treatment can be discontinued and the horse can be put back to work. If levels of these enzymes are not elevated in the blood, then problems other than tying-up must be considered.