Laminitis is a condition we see very commonly. In simple terms, it describes inflammation of the laminae within the hoof capsule. The laminae attach the pedal bone to the hoof wall. The precise reason why this damage takes place is poorly understood, however the resulting damage can have devastating consequences within the hoof capsule.
What causes it?
Over 90% of laminitis cases are what we describe as endocrine laminitis cases.
Endocrine associated laminitis includes the 2 conditions we associate most with laminitis-Cushing's Syndrome and Metabolic Syndrome.
Cushing's Syndrome (Pituitary Pars Intermedia Dysfunction)
- most commonly seen in older patients (see notes on Cushing's Syndrome)
Equine Metabolic Syndrome
- most cases have excess fat deposits and hence become insulin resistant
- insulin resistance leads to the development of high circulating levels of insulin
- high levels of insulin lead to damage to laminae and hence laminitis
Sometimes we can see laminitis cases associated with other conditions
If a horse has a severe lameness with one limb it will often overload the opposite leg which can sometimes lead to the development of laminitis within this limb.
In severe cases of septicaemia and colic we can sometimes see laminitis develop secondary to the toxic effects on the laminae.
Symptoms of Lamintis
The symptoms of laminitis can vary between horses but the most common symptoms reflect the fact that the feet, especially the toes are painful. Many horses will be reluctant to move and may be found unwilling to walk, or at least very stiffly.
Often the feet will be warm, and the horse may be shifting weight from one foot to another. It is often possible to palpate the digital pulse (see video for further details). Many horses will adopt the classic 'rocked back' appearance as they try to take weight off the front of their feet.
What to do?
The first thing to do when you suspect laminitis is to contact your veterinary surgeon. The biggest priority is to relieve the pain and discomfort they are in and your vet will be able to administer pain relief in the form of either an injection or as oral medication.
Restricting movement is very important, so we almost always recommend the horse be brought in and put on a deep bed of shavings. The deep bed of shavings helps to support the foot and prevent any movement of the pedal bone within the foot.
We will often use dental impression material to make a pair of supports for your horse's feet. The aim of these is to support their weight in an attempt to reduce the likelihood of any movement of the pedal bone.
Unfortunately, in severe cases, the attachment between the hoof wall and the pedal bone becomes so damaged and weak that further changes take place. As we described earlier, the laminae are there to hold the pedal bone in position. If they are damaged to the point whereby they cannot support the weight of the horse then it is possible for the pedal bone to move within the hoof.
We sometimes can suspect this if we see certain changes on the sole of the foot, or at the coronary band. To investigate further we will take radiographs to assess the position of the bone. Using these radiographs, we can then calculate how much rotation or sinkage there has been. This allows us then to identify what the prognosis for the horse may be, and how best to manage them.
The key to managing any case of laminitis is to identify what the original cause was. The most likely cause may be easily evident- for example an overweight 6 year old Welsh Pony is most likely to have Metabolic Syndrome and Insulin Resistance, whereas a 28 year old hairy thoroughbred is more likelyto have Cushing's Syndrome. It is also possible to have both though, and following a diagnosis of laminitis we will always try to identify all the causes and address them.
Remember LAMINITIS is a SYMPTOM not a disease !!!
For more information about Cushings Syndrome, see section on Advice For Horse Owners above.
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New House Farm, Belbroughton Rd, Blakedown DY103JH