Рабдомиолиз у лошадей: причины, симптомы и лечение.

Equine exertional rhabdomyolysis (ER) is a syndrome that affects the skeletal muscles within a horse. This syndrome causes the muscle to break down which is generally associated with exercise and diet regime. Depending on the severity, there are various types of ER, including sporadic (i. e., Tying Up, Monday Morning Sickness/Disease, Azoturia) and chronic (i. e., Polysaccharide Storage Myopathy (PSSM) and Recurrent Exertional Rhabdomyolysis (RER)).

A horse may need fluids, especially if its urine is colored, it is receiving NSAIDs, or it is dehydrated. Fluids increase the production of urine that, in turn, helps flush out the excess, and potentially damaging, myoglobin from the kidneys and reduce NSAID produced kidney damage. Fluids should be administered until the urine is clear, which usually takes from a few hours to a few days. Vasodilators, such as acepromazine, can help improve blood flow to the muscles, but acepromazine only should be administered if it is prescribed by a licensed veterinarian, as it can lower the animal's blood pressure and can cause collapse in a severely dehydrated horse. The human drug dantrolene is sometimes given to alleviate the muscle spasms and prevent further degeneration of muscle tissue. Vitamin E is an antioxidant, so may help prevent further cell degeneration in the affected muscles. However, vitamin E products must be used with caution if they also contain selenium. Bicarbonate does not help offset any lactic acid in the bloodstream, as lactic acid generally only accumulates in the affected muscles. Except to get to its stall, a horse showing signs of severe ER should not be moved until comfortable enough to do so eagerly. This may take several days. After this point, hand walking the horse a few times each day or turnout in a pasture or paddock is needed.

For horses who exhibit chronic ER, treatment will vary according to genetic and in some cases breed. Management is key for treating horses with Chronic ER as in most cases this type of ER doesn't go away. Reducing the trigger effects will help with management of the animal. In some cases a licensed veterinarian may prescribe tranquilizers if the horse is thrashing or nervous. This will help to keep the horse calm and provide some pain relief. Tranquilizers may also be advised to be used during training upon the horse returning to work. Changing diet regime to a high fat low starch can be beneficial for the horse, as it can help with excitement.

Symptoms may take several days to several weeks to subside, all depending on severity and type of ER. If initial symptoms have subsided a horse may be allowed turn out. A horse may be returned to work if symptoms have ceased and is no longer on NSAIDs or other prescribed drugs related to treatment of ER, this can otherwise can hide signs of another bout of ER. If NSAIDs or other treatment drugs are needed to keep the horse comfortable, or if the horse is reluctant to continue work, the animal is not yet ready for a return to its regular training program. Blood tests such as Creatine Kinase Concentration (CK), Aspartate Transaminase Levels (AST), and/or Lactate Dehydrogenase (LDH) should be normal before the horse is returned to work.

Depending on the damage and destruction to the muscle tissue prognosis can vary. Prognosis can also vary depending on type and severity as well. However some signs of a positive prognosis may include, a horse being able to stay up and not lying down too much, keeping the horse quiet can also help with the healing factor, if the horse appears to be back to normal within 24 hours the prognosis outlook is better. There are also possibilities that a horse may showcase lameness and/or permanent damage to muscles. In some cases if horse goes into kidney failure due to untreated myoglobinuria, results could be fatal.

For bouts of Sporadic ER, reducing any extra energy in a horse's diet is essential. Decreasing carbohydrates and increasing the daily intake of hay or pasture can usually accomplish this. Grain may need to be cut in half and feed ration should also be downsized prior to rest days. Feeding a well balanced diet of both vitamins and minerals can also be beneficial. For bouts of Chronic ER, a high fat low starch diet can be beneficial. Gradually the horse should be introduced to this new diet. For some cases of Chronic ER such as RER, the horse may need a higher intake of calories. This is where feeds specially created and designed for ER will be necessary.

For bouts of Sporadic ER proper conditioning is essential in prevention. IN using proper training techniques a horse should be warmed up thoroughly before intense training and/or riding. The same should be done when cooling down. Ensure that the horse is cared for, for an issues to the immune system and allowed to recover before continuing training. A horse ideally should receive exercise once, or possibly twice a day, every day, to prevent the recurrence of ER. If possible, avoid breaks in the horse's exercise schedule. For bouts of Chronic ER depending on type, the focus should be on preventing overexcitement. This can be accomplished by allowing pasture time, utilizing a hot walker, and minimizing stall time. Horses with Chronic ER should also be injected with a low dose tranquilizer during intense training, to help with overexcitement, this however is more for the RER type of Chronic ER.

As with any supplements and drugs, conferring with a veterinarian as to the recommended dosages is best. Some drugs are not allowed in competition and may need to be withheld a few days before. Adding potassium and salt to the diet may be beneficial to horses that suffer from recurrent bouts of ER both chronic and sporadic. Horses in hard training may need a vitamin E supplement, as their requirements are higher than horses in more moderate work. The horse may also be deficient in selenium, and need a feed in supplement. Selenium can be dangerous if overfed, so a blood test to confirm that the horse is in need of supplemental selenium should be used. Other drugs that have been used with success include phenytoin, dantrolene, and dimethylglycine.