The last eight years have seen an unprecedented leap forward in our understanding of what causes laminitis, and this has significantly improved the way that we are now able to manage this debilitating and painful condition in our horses and ponies.
One of the most important discoveries has been the realisation that 90% of laminitis cases have an underlying hormonal cause.1
Talk About Laminitis (TAL) has been working since 2012 to raise awareness of this link between laminitis and hormonal disease, so that laminitic horses can be routinely tested for hormonal disease and therefore managed appropriately depending on their diagnosis.
There are two hormonal diseases which are commonly associated with laminitis: Equine Cushing’s disease (PPID) and EMS (Equine Metabolic Syndrome).
Most horse owners are aware that laminitis is an inflammatory condition of the hooves which causes lameness in horses and ponies.
However, recent research has shown that in many horses and ponies there is a period where laminitis is present and causing changes to the hooves, but lameness is not yet evident. Picking up these early signs of laminitis before there is any pain associated with the condition gives owners and vets the opportunity to adjust management strategies and treat underlying disease with the aim of preventing a painful episode of laminitis developing.
If you would like to learn more about what is happening inside a laminitic horse’s hooves, take a look at our sister website www.careaboutcushings.co.uk which has more information about this.
Laminitis can be classified into three main types:
This is where a septic condition, such as an infection of the uterus (toxic metritis), causes laminitis.
This is where severe lameness in one limb, for example after fracture fixation, and the subsequent increase in weight-bearing by the opposite limb, results in laminitis of that opposite limb.
This is by far the commonest form of laminitis, and is where laminitis occurs in association with hormonal disease (endocrine disease).
A paper published in 2018 titled ‘Paradigm Shifts in Understanding Equine Laminitis’2 recognises the recent advances in our understanding of what causes this important disease, and describes three paradigm shifts that have taken place over the last few years.
Historically it was thought that laminitis was a disease of the foot and hoof, but now it is understood that laminitis is a group of clinical signs and laboratory findings that can result from several different systemic (whole-body) diseases (or sometimes from increased weight-bearing in the supporting limb of a lame horse).
This means that accurate diagnosis of the associated systemic disease (or abnormal weight-bearing) is pivotal to managing laminitis effectively and preventing recurrence.
Historically it was thought that the main cause of laminitis was pasture consumption, but now it is understood that hormonal laminitis (endocrine laminitis) is the most common cause of laminitis where horses present primarily for lameness.
This means that we need to be vigilant is looking for systemic hormonal disease in all laminitis cases that present primarily for lameness.
Historically it was thought that the most important change in laminitic hoof was associated with a structure called the basement membrane, but now we understand that the earliest changes in the hoof are in the lamellar cells, and that this represents an early sub-clinical phase of laminitis. In some horses this sub-clinical phase is evidenced by the appearance of divergent hoof rings.
This means that the presence of divergent hoof rings may signify a window of opportunity for treatment of early stages of laminitis before they progress to becoming painful for the horse.
As discussed in the second paradigm shift above, now we know that the most important factor that influences whether a horse develops laminitis is the presence of hormonal disease.
There are two hormonal conditions that are known to be associated with laminitis: PPID (Pituitary Pars Intermedia Dysfunction, also known as Equine Cushing’s disease) and EMS (Equine Metabolic Syndrome). The exact mechanisms whereby these hormonal diseases cause laminitis is currently unknown although both diseases are associated with high levels of insulin in the bloodstream (hyperinsulinaemia) which is known to cause laminitis. There are a variety of tests which can be used to investigate whether a horse or pony has one of these hormonal conditions: these include the basal ACTH test for Equine Cushing’s disease (PPID) and basal insulin (to look for hyperinsulinaemia).
If your horse develops laminitis it is recommended that you test for PPID if he/she is over 10, and that you test the insulin levels and assess body condition to determine whether EMS is present. An individual horse can have EMS and PPID concurrently, and therefore it is usually worth testing for both conditions.
The signs of laminitis can be broadly grouped into two groups: signs associated with hoof changes, and signs associated with hoof pain.
You can use our laminitis checklist to assess whether your horse or pony is showing any signs that may be associated with laminitis.
Severe laminitis is an emergency, and ongoing ‘moderate’ disease can result in painful long-term consequences. Prompt attention and treatment as soon as the signs of laminitis are recognised will not only relieve the pain, but also reduce the long-term damage.
1) Seek veterinary advice
2) Until the vet arrives:
When the vet arrives they will examine your horse. If they confirm a diagnosis of laminitis, they will treat the painful symptoms and make recommendations with respect to trimming, farriery, and management. The vet may also test for underlying hormonal conditions: identification and treatment of these may reduce the risk of future painful attacks and permanent damage.
If your vet considers a test for Equine Cushing’s disease (PPID) to be appropriate for your horse, they can claim a voucher for a complimentary* blood test on your behalf.
More information about laminitis and Equine Cushing’s disease is available on our Care About Cushings website.
Care About Cushings members benefit from access to even more information about Equine Cushing’s disease. Register for membership below.
1. Karikowski et al 2011 The prevalence of endocrinopathic laminitis among horses presented for laminitis at a first opinion/referral equine hospital Domestic Animal WEndocrinology 41 111-117.
2. J.C.Patterson-Kane et al 2018 Paradigm shifts in understanding equine laminitis The Veterinary Journal 231(33-40)
The Talk About Laminitis initiative continues to do sterling work in awareness-raising but also crucially in increasing the information we have about the disease and related conditions.
PPID (Cushing’s disease) is a significant risk factor for developing the devastating disease of laminitis, but thanks to this initiative, more cases can be identified early.
We encourage all horse owners, who are concerned about PPID in their horses, to take up this fantastic complimentary offer.