Laminitis

What is it?  The definition of laminitis is the inflammation of the sensitive lamina of the hoof capsule.  This means that the layers of tissue holding the hoof wall to the coffin bone get painful, hot, and can eventually lose their ability to support the weight of the horse.  When this occurs, the coffin bone may pull away from the hoof wall through rotation or sinking.  It is this complication that makes laminitis a life threatening disease since, unfortunately, no treatment options are effective once the coffin bone has rotated or sunk past a certain point.  Laminitis can occur in any one or all four feet, although it is most commonly seen in both front feet.

Causes:   The exact physiological processes leading to laminitis are not completely understood.  However, we do know that several factors predispose horses and ponies to this disease.  Most often laminitis is seen secondary to some other disease or from over consumption of grain or lush pastures.  Some diseases predisposing horses to laminitis are: severe colic, retained placenta or metritis (uterine infection) in mares, severe diarrhea, high fever, and Cushing’s disease in older horses.  Other causes of laminitis are: prolonged work on hard surfaces (“road founder”), animals being overweight (especially ponies), and excessively long hooves.

Clinical Signs:  Lameness is almost always seen in cases of acute (or sudden) laminitis.  The type of lameness seen will depend on the foot or feet affected as well as the severity of the disease.  Most cases of laminitis are seen in the front feet, these horses will stand with their front legs out in front of them and their hind legs pulled forward under their body (“campy” or “camped out” appearance).  This altered stance helps position more of the body weight on the back legs and alleviates pressure on the sore feet. 

Other signs associated with laminitis include:

·        reluctance to allow feet to be picked up

·        reluctance to walk

·        lying down more than usual

·        short and choppy gait

·        increased heat at the coronary band

·        increased digital pulses (felt at the four o’clock and eight o’clock positions at the level of the fetlock).

Diagnosis and Treatment:  Often the diagnosis of laminitis can be made on the basis of the animal’s history and clinical signs.  X-rays are often very useful to determine the severity of the condition and to establish a baseline to measure the progression of the disease.  Treatment of laminitis usually depends on correction of the underlying process.  If the animal recently got into grain or lush pasture, then removing the stomach contents via nasogastric tube may help prevent laminitis from developing.  If the laminitis is caused by another disease, identification and treatment of the underlying disorder is essential to minimize damage to the horse’s feet.  Other therapies will depend on the severity the duration of the disease.  Most often these involve supportive measures such as judicious use of pain killers such as phenylbutazone, special hoof trimming and shoeing, placing pads underneath the horse’s feet, and extra bedding to prevent decubital ulcers (bed sores) if the horse spends a lot of time lying down.

If you suspect your horse is developing laminitis call your veterinarian immediately.  Treatments initiated in the early stages of the disease are much more effective and are more likely to help the horse return to normal function.