Managing a Horse with PSSM2/MIM

In case of an acute episode of tying-up: stop any kind of forced movement to limit further muscle damage and pain and give the horse a place where it can rest, away from possible stressors, including other horses that may want to force it to move - and call your veterinarian. Keep the horse warm while you wait for your vet to arrive, especially when temperatures are low. Your vet will most likely administer muscle relaxants and painkillers. Medication is not only  important for your horse’s comfort, but also to prevent further muscle damage or additional cramping, which could cause the episode to continue or worsen. Your vet may want to take a blood sample to assess the extent of muscle damage. Please note that horses with MIM do not necessarily show elevated LDH and CK values in their blood, even when they experience an episode of tying-up.

In order to prevent escalation of symptoms, pain medication may also be beneficial when less severe symptoms present themselves, because horses experiencing muscle pain often compensate by altering their stance or way of moving, causing compensatory additional strain on additional muscle groups. Consult with your veterinarian if it is possible to stock pain medication (flunixin paste) so  you are able to catch episodes more quickly before they worsen. As a preventative measure, it can be beneficial to administer muscle relaxants and/or pain medication before and during certain procedures, such as dentistry. If you know your horse will be exposed to stress or medical care (such as dentistry, vaccination, gelding, fireworks, a move) it can be beneficial to start increasing the amount of vitamin E and the amount of protein the horse is getting as a preventative measure. Illness and medical interventions cause a negative nitrogen balance in the body, which is a known trigger for a PSSM2/MIM episode.

The two main factors in managing a horse with PSSM2/MIM are nutrition and exercise.