chronic | Horse Racing Free Tips

Pain Management Strategies for Laminitic Horses: Different Solutions For Different Causes

Very few equine conditions can be as debilitating as laminitis, which can be triggered by a variety of events or occur on its own. Laminitis occurs when the laminae, a set of finger-like structures which support the coffin bone and hold it in place in the hoof capsule, become inflamed. This inflammation is incredibly painful and can be catastrophic for the horse's athletic career.

Many horses that develop laminitis are not euthanized because of the changes to the laminae, but because of the uncontrollable pain the condition brings on. A virtual session of the 2020 American Association of Equine Practitioners annual convention summarized the current research on the best way to manage pain in different types of laminitis cases.

The pain a laminitic horse feels is multidimensional. It can be brought on by pressure within the hoof capsule, inflammation of the laminae, tearing of soft tissues, a reduction of blood supply to the hoof, contact between the coffin bone and the sole of the hoof, and neuropathic pain.

Dr. Katherine Ellis of Gail Holmes Equine Orthopaedic Research Center at Colorado State University, explained several different strategies for different causes of laminitis. Phenylbutazone (bute) is commonly given to treat laminitis, but that other drugs, including as flunixin, ketoprofen or firocoxib, may be better at controlling laminitic pain.

Ellis stressed that if an NSAID doesn't seem to be providing pain relief to a laminitic horse, another should be considered. A horse that has developed laminitis from overindulging in grain would benefit from having his hooves submerged ice water. This will be helpful for controlling pain and limiting injury. Ideally, the hooves would be submerged constantly for 48 to 72 hours, though this is a labor-intense endeavor.

Metabolic issues like equine metabolic syndrome (EMS) and Cushing's disease can put a horse at risk for chronic laminitis. Gabapentin has been shown to be an effective pain medication for horses with chronic laminitis, but higher doses of pain medications may be necessary to provide relief.

Ellis noted that acupuncture and use of a TENS unit may offer some additional pain relief. Chiropractic work and massage may offer respite from body pain brought on by the laminitic stance.

A horse that has an injury to a leg may develop supporting limb laminitis. Ellis suggests using morphine and butorphanol blocks and fentanyl patches to help control pain in these cases. A tramadol and ketamine infusion can also be used. Ellis notes that biologics like stem cells and platelet-rich plasma can be used for the anti-inflammatory properties.

Cellulitis: A Challenging Condition To Cure

Cellulitis is a sudden, painful skin infection that requires aggressive, immediate care. Most commonly affecting the hind legs, many horses recover readily, but complications are possible, and chronic flare-ups are a possibility.

Cellulitis occurs when bacteria penetrate the epidermis of the skin and multiplies in the subcutis, which is made up mainly of fatty and connective tissues. Primary cellulitis has no specific point of origin and exactly how it penetrates the skin is often unknown. Secondary cellulitis occurs when bacteria enter tissues through a known route, like a wound or surgical incision.

Cellulitis can be caused by a variety of bacteria and needs to be treated promptly. Left untreated, the infection can affect bone, tendon or synovial structures. Sepsis and laminitis can also occur.

Signs of cellulitis include:

Dramatic swelling that comes on rapidly and feels firm
Heat
Pain that tends to appear when the horse is asked to step forward rather than bear weight
Fever
Wetness: the swelling can progress rapidly to the point where fluid leaks from cracks in skin that is overstretched

A vet may take X-rays or do an ultrasound to rule out other possible issues like a joint infection or fracture. He or she may also culture the fluid weeping from the leg; this will help determine what bacteria is involved so that the proper antibiotic can be administered.

The primary treatment for cellulitis is intravenous antibiotics, as well as nonsteroidal anti-inflammatories to help with pain and swelling. Cold hosing or ice boots or bandaging can also help.

Horses with secondary cellulitis tend to recover more rapidly. Though some cases of cellulitis can be managed at home, severe cases may need to be referred to an equine hospital.

Horses that have had even one episode of cellulitis become susceptible to chronic cellulitis, specifically in the same limb, whether the skin was permanently damaged from the extreme swelling or because circulatory and lymphatics systems have been damaged to the point that they are unable to mount an immune response. Horses that have had cellulitis even once should be monitored carefully as even the tiniest wound may initiate a new round of cellulitis.

Tips to avoid cellulitis recurrence:

Turn out the horse as much as possible in dry condition
Use shampoo sparingly when bathing
Avoid sharing grooming tools and sterilize them regularly

Chronic Pain Can Be Detected In Equine EEGs

Chronic pain is difficult to assess as it involves subjective emotional and cognitive facets. There has been increasing interest in using electroencephalograms (EEGs), which measures brain waves, on resting horses to help determine if the horse is experiencing chronic pain. EEGs have been used as a tool in human medicine to help decipher chronic pain.

Riding horses are prone to chronic back pain; horses that experience this pain show lower levels of engagement and shorter attention spans. Drs. Mathilde Stomp, Serenella d'Ingeo, Séverine Henry, Clémence Lesimple, Hugo Cousillas and Martine Hausberger hypothesized that horses with chronic back pain would have resting-state EEGs that differed from horses that were pain-free.

The researchers fitted 18 horses with a headset and a telemetric recorder. The horses stood in a covered arena while they underwent back evaluations that noted the back's shape and muscular tension, as well as took precise spinal measurements. Thirteen of the horses had surface electromyography (sEMG) exams to measure muscle activity; each horse was monitored for 60 minutes to see if they had any stereotypic behavior.

The scientists found that the horses had consistent EEG profiles over time. Horses that were assessed as having back pain had resting-state EEGs that had more fast waves and fewer slow waves. The study team also linked back tension to the frequency of stereotypic behaviors. They scientists concluded that resting-state EEGs are a promising tool to assess chronic back pain in horses.

Read the full study here.