Tie up is one of the alternative terms for a condition called exertional rhabdomyolyisis (ER). There are a number of possible causes but the most common of these is over exertion. This causes damage to muscles, particularly in the hindlimbs and hind quarters, leading to the clinical signs of the condition.
The classic signs of ER are extreme stiffness and reluctance to move. Other signs that may be seen are sweating, hard, painful muscles over the hind quarters, increased respiration rate and dark/red urine.
A diagnosis of ER may be possible based on history and clinical signs alone. However, in many cases your vet will take a blood sample to check for any elevation in the muscle enzymes, creatine kinase (CK) and aspartate aminotransferase (AST), to confirm their diagnosis. These enzymes are released by damaged muscle and the extent of their increase reflects the severity of the damage.
Follow up bloods may be taken to monitor your horse’s recovery.
It may be necessary to conduct further blood tests and take urine samples to check the health of your horse’s kidneys. This is important because the characteristic red urine that ER can cause is due to myoglobin being released from the damaged muscle cells. Myoglobin is toxic to kidneys and their function must be monitored for any sign of damage to ensure your horse receives the required treatment.
Shotter & Byers has a blood machine that allows us to conduct these tests in house to ensure we rapidly have the information we need allowing us to provide your horse with the very best care.
Treatment of ER is dependent on the fundamental cause. Although it usually involves box rest to allow the damaged muscle to recover.
Anti-inflammatories may be given to decrease inflammation and provide pain relief. It may also be warranted to give more stronger pain relief, sedation and anti-anxiety drugs to calm your horse and aid muscle relaxation.
The risk ER poses to the kidneys makes it is extremely important that your horse is well hydrated. Depending on the severity of the ER and level of dehydration this can involve passing a nasogastric tube to give water or the administration of intravenous fluids.
ER can be avoided by ensuring your horse stays fit and that they are well warmed up before strenuous exercise. An hour of exercise a day is better than 5 hours in one day! In some cases, the risk of ER can be lowered by decreasing the amount of concentrate feed. Good quality forage is the most important part of your horse’s diet. If your horse requires extra calories, these can come from the addition of oil to the feed without predisposing for ER.