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and potentially have detrimental effects on healing. Movement can help reduce pain and maintain range of motion, as well as providing low level appropriate stress to the healing muscle. If a focal area of muscle damage has been identified, application of ice may be the most appropriate method of providing analgesia and anti-inflammatory effects. If the affected muscle is relatively thin and superficial, it can be iced for 10 minutes several times per day. If it is a larger muscle mass, then more prolonged application of ice (20 mins) can be performed several times per day. Other treatment modalities have the potential to provide analgesia and facilitate return of function, including therapeutic ultrasound, cold laser, acupuncture, and massage. These can be used in combination for severe focal injuries, however, preliminary investigations indicate that laser and ultrasound are probably limited substantially by restricted penetration depth. In regard to pharmacologic management, although nonsteroidal anti-inflammatory medications are frequently used for suspected or confirmed muscular injuries, evidence in other species suggests that they can significantly delay healing due to disruption of muscle satellite cell function and other critical processes. Therefore they should be used judiciously, and only in cases where significant pain and inflammation necessitate their use. Muscular injuries that are associated with significant pain, rhabdomyolysis or impaired movement may also benefit from the use of muscle relaxants, including methocarbamol, phenytoin, diazepam or dantrolene sodium. These are often most beneficial in the acute stage when there is significant pain and/or loss of function, and potentially when large muscle groups are affected. The most well studied of these drugs in regard to muscular disorders is dantrolene sodium. The pharmacokinetics and clinical effects of this drug are published for horses. Dantrolene is a skeletal muscle calcium channel blocker which can be dosed orally in horses and which has utility in the treatment of severe or diffuse muscle injuries creating pain, lameness, and/or myoglobinuria. It prevents muscle necrosis and can speed healing and return of function. In horses it can be dosed at 4 mg/ kg per os two to three times daily (preferably accompanying recent feed intake) during initial treatment of significant muscle injury. However, it should probably be avoided in horses with uncertain or positive HYPP status, since it can induce hyperkalemia (only demonstrated after prolonged general anesthesia at this time).

Once control of pain and inflammation is achieved, horses can be exposed to escalating exercise routines that accommodate their limitations and encourage functional motion within the affected muscle group, applying appropriate limits to avoid re-injury. It is important to develop an individually appropriate warm-up routine to help with transition to more demanding exercise by preparing relevant muscle groups. Ideally, horses should have a regular (i.e. three to seven times per week) exercise routine since intermittent training has been shown to exacerbate episodes of rhabdomyolysis in horses with predisposing conditions, and higher post-exercise serum muscle enzyme activities have been demonstrated in healthy horses training two versus three times per week. Training volume should be incrementally increased over time, and a solid base of weeks to months accrued before any return to intensive or explosive exercise. Where possible, stall rest should be minimized and pasture turnout emphasized with appropriate companionship that does not encourage over-activity or traumatic interactions. Serial monitoring of muscle enzymes can be performed (e.g. pre- and post-competition) where underlying muscular disorders or repeat injury is possible. An example protocol for rehabilitating a horse with a significant hindlimb muscle injury might commence with seven to 14 days of directed treatment for pain and inflammation, encompassing ice, very light hand walking with stall restriction, and systemic or topical non-steroidal agents if required for severe pain or inflammation. Soft tissue mobilization above and below the area of concern can also provide pain relief and improve mobility and can continue over weeks if it appears to provide improvement. Direct massage of the injury site should be avoided initially, though crossfrictional massage followed by fiber direction massage has

Image 4: Horse warming up

8  The Practitioner†Issue 4 • 2017

Profile for FVMA

Practitioner Issue 4, 2017  

A publication by the Florida Association of Equine Practitioners, an equine-exclusive division of the FVMA. Your Invitation to Attend the Oc...

Practitioner Issue 4, 2017  

A publication by the Florida Association of Equine Practitioners, an equine-exclusive division of the FVMA. Your Invitation to Attend the Oc...

Profile for fvma_faep