Changes

* Access to lush pastures - particularly in the early morning when high levels of fructans are present in the grass

* Access to lush pastures - particularly in the early morning when high levels of fructans are present in the grass

* Grain overload (Ingestion of large quantities of soluble carbohydrates)

* Grain overload (Ingestion of large quantities of soluble carbohydrates)

* Retained Placenta, colic, diarrhoea and any other systemic illness causing endotoxaemia

* Retained Placenta, [[Colic|colic]], diarrhoea and any other systemic illness causing endotoxaemia

* Animals having little exercise

* Animals having little exercise

* Pituitary Pars Intermedia Dysfunction / Equine Cushing's

* Pituitary Pars Intermedia Dysfunction / Equine Cushing's

* Equine Metabolic Syndrome

* Equine Metabolic Syndrome

* Trauma/excessive work on hard surfaces

* Trauma/excessive work on hard surfaces

* Increased weight bearing on one limb

* Increased weight bearing on one limb - normally caused by lameness in the contralateral limb.

* Pony breeds

* Pony breeds

== Pathogenesis ==

== Pathogenesis ==

Acute disease develops rapidly and most commonly occurs in the front feet. In the early stages of disease or if the case is mild the horse presents as reluctant to move, with frequently shifting of weight between the affected feet and a characteristic stilted gait.

Acute disease develops rapidly and most commonly occurs in the front feet. In the early stages of disease or if the case is mild the horse presents as reluctant to move, with frequently shifting of weight between the affected feet and a characteristic stilted gait.

In more severe cases the horse normally presents with a characteristic posture in which the horse appears to be leaning back on its heels. In this posture the feet are placed normally but the head is low, the back arched as the horse attempts to relieve the pressure on the toe, particularly in the fore-feet. The horse may also be unwilling to move or pick up its feet and can potentially collapse if it is forced to do so. Signs of pain such as anxiety, sweating, increased heart and respiration rate are frequently seen.  

In more severe cases the horse normally presents with a characteristic posture in which the horse appears to be leaning back on its heels. In this posture the feet are placed normally but the head is low and the back arched as the horse attempts to relieve the pressure on the toe, particularly in the fore-feet. The horse may also be unwilling to move or pick up its feet and can potentially collapse if it is forced to do so. Signs of pain such as anxiety, sweating, increased heart and respiration rate are frequently seen.  

In the most severe cases there may be serum like exudate at the coronary band and the hoof may become detached and shed. Although this does indicate a bleak prognosis, with good and dedicated owners, vets and farriers who are prepared for the time and cost of treatment the horse can survive sloughing of the hoof and go back to normal work.

In the most severe cases there may be serum like exudate at the coronary band and the hoof may become detached and shed. Although this does indicate a bleak prognosis, with good and dedicated owners, vets and farriers who are prepared for the time and cost of treatment the horse can survive sloughing of the hoof and go back to normal work.

== Diagnosis ==

== Diagnosis ==

Diagnosis should be based on clinical signs and patient history. Pain may be present on palpation around the coronet and the horse may display a marked withdrawal in response to hoof testers. Increased height and strength of pulse in the palmer digital artery

Diagnosis should be based on clinical signs and patient history. Pain may be present on palpation around the coronet and the horse may display a marked withdrawal in response to hoof testers. The height and strength of pulse in the palmer digital artery is normally increased. If the pedal bone has sunk a concavity may be palpable at the junction of the coronet, and in very severe cases the pedal bone may be visible through the sole of the hoof. Definitive diagnosis is achieved using radiography.  

If the pedal bone has sunk a concavity may be palpable at the junction of the coronet, and in very severe cases the pedal bone may be visible through the sole of the hoof. Definitive diagnosis is achieved using radiography.  

=== Radiography ===

=== Radiography ===

* Rotation of the pedal bone as a tilting of the distal aspect towards the sole

* Rotation of the pedal bone as a tilting of the distal aspect towards the sole

* Sinking of the pedal bone (which is the main indicator of prognosis).

* Sinking of the pedal bone (which is the main indicator of prognosis).

Serum build up may be evident as a radiolucent line between the dorsal hoof wall and the pedal bone.

Serum build up may be evident as a radiolucent line between the dorsal hoof wall and the pedal bone. In chronic cases the pedal bone may even develop the appearance of a Turkish slipper, as a result of the pressure placed on tip of the rotated P3.  

You should measure:

You should measure:

* Distance between the top of the hoof wall the top of the extensor process of pedal bone

* Distance between the top of the hoof wall the top of the extensor process of pedal bone to assess rotation of P3

* Distance between dorsal hoof wall and dorsal cortex of pedal bone

* Distance between dorsal hoof wall and dorsal cortex of pedal bone to assess sinking of P3

== Prognosis ==

 

== Treatment ==

 

 

 

Several factors effect the prognosis in laminitis cases. The pursuit of treatment and the likelihood of its success is very dependant of financial and emotional commitment of the owners.

Analgesics, mainly [[NSAIDs]] (Phenylbutazone) and box rest are the standard treatments. Other available NSAIDs are Flunixin Meglumine, Ketoprofen and Dimethyl Sulfoxide.

Larger and heavier animals carry a poorer prognosis, as do animals with a greater number of affected feet. Clinical signs help guide prognosis but there are big differences between the signs displayed by stoical and relatively wimpy horses, and it is considered better to use response to treatment in the individual horse as a guide. The Obel grading system was developed (in 1948) to help grade prognosis, with lower grade horses having a better prognosis:

As the pathogenesis of laminitis is not fully understood there is some controversy surrounding the use of some drugs and the theories behind their use - such as vasodilators and anticoagulants. Therefore it is up the individual clinician to decide whether these drugs are indicated. However it is unanimously agreed the box rest and anti-inflammatory drugs are the mainstays of treatment.

'''GRADE 0'''. There is no lameness at walk or straight trot on a hard surface

Mechanical support is important and may provide some pain relief and help prevent rotation or sinking of the pedal bone. It can be done with polystyrene or other packing materials or by keeping the animal on soft, deep bedding. Elevating the heel with a wedge or wedge shoe may be useful to take off some of the strain on the deep digital flexor tendon and help to reduce rotation. The farrier will be able to help with the use of egg bar, heart bar and plastic shoes.

'''GRADE 1.''' At rest, the horse alternately lifts its feet, but no lameness is observable at walk. There is a short stilted gait at straight trot on a hard surface and when turned at walk

Horses should be fed on a very low energy diet of soaked hay. Low carbohydrate, high fibre concentrates such as 'Hi-Fi' or 'Happy Hoof' may be added in small quantities if appropriate.  

'''GRADE 2.''' The horse does not move freely at walk and has a ‘stiff’ gait. At trot on a hard surface, the animal has a short stilted gait, and it turns with great difficulty. A foot can be lifted off the ground without great difficulty

The response to treatment should be monitored physically and radiographically.  

'''GRADE 3.''' The horse is reluctant to move at walk on any surface. It is difficult to lift a limb and the animal might be virtually non-weightbearing on the affected limb

It should be stressed that management plays a huge role in both the management of an active case of laminitis and in preventing its recurrence in the future. Recovery from laminitis may be prolonged especially in severe cases, and return to work should always be gradual. In the cases where an underlying cause (e.g. Cushing's Disease) is suspected, this should be identified and treated appropriately.

'''GRADE 4.''' The horse will not move without coercion. It is particularly reluctant to move from a soft to a hard surface and it is almost impossible to lift a limb

In very severe cases the only option may be euthanasia.

Radiography is the main tool required for prognostics. It is generally recognised that the worse the rotation of the pedal bone the less chance of returning to athletic function. However there should not be too much emphasis placed on pedal bone rotation when considering the prognosis. The fast rate of rotation is suggestive of further structure collapse - repeat radiographs are useful when assessing this.

Overweight and unfit animals should be managed appropriately with diet and exercise changes. Horses with a history of laminitis should not be allowed to graze lush pasture, especially in Spring and Autumn and early in the morning. Following injury or lameness to one limb, the other limbs should be monitored closely for signs of laminitis (increased heat and digital pulses) and the animal placed on a deep bed to help prevent it occuring. In horses where endotoxaemia may develop, anti-endotoxic drugs such as NSAIDS should be given as they may prevent the development of laminitis. As mentioned, in the cases where an underlying disease is suspected, this should be identified and treated appropriately.

Symptoms of the following diseases can be similar but there is no pain in the feet:

'''GRADE 0'''. There is no lameness at walk or straight trot on a hard surface

Acute laminitis is an '''emergency'''. Box rest is an important part of treatment and return to work should be very gradual.

'''GRADE 2.''' The horse does not move freely at walk and has a ‘stiff’ gait. At trot on a hard surface, the animal has a short stilted gait, and it turns with great difficulty. A foot can be lifted off the ground without great difficulty

'''GRADE 3.''' The horse is reluctant to move at walk on any surface. It is difficult to lift a limb and the animal might be virtually non-weightbearing on the affected limb

* Relieve pain and reduce inflammation

* Dilate blood vessels in the foot

* Prevent rotation or sinking of the pedal bone

Analgesics, mainly [[NSAIDs]] (Phenylbutazone) are the main treatment. It may also help break the theorised pain-hypertension-vasoconstriction cycle.

'''GRADE 4.''' The horse will not move without coercion. It is particularly reluctant to move from a soft to a hard surface and it is almost impossible to lift a limb

Other available NSAIDs are Flunixin Meglumine, Ketoprofen and Dimethyl Sulfoxide.

Mechanical support is important and may provide some pain relief and help prevent rotation or sinking of the pedal bone. It can be done with polystyrene or other packing materials or keeping the animal on soft, deep bedding. Elevating the heel with a wedge or wedge shoe may be useful to take off some of the strain on the deep digital flexor tendon and help to reduce rotation. The farrier will be able to help with the use of egg bar, heart bar and plastic shoes.

'''GRADE 5.''' The horse is mostly recumbent and will not stand for more than a few minutes

Treatment should be monitored physically and radiographically.

Radiography is the main tool required for prognostics. It is generally recognised that the worse the rotation of the pedal bone the less chance of returning to athletic function. However there should not be too much emphasis placed on pedal bone rotation when considering the prognosis. A fast rate of rotation is suggestive of further structure collapse - repeat radiographs are useful when assessing this. The level of sinking of the pedal bone is the main prognostic indicator, with distal movement of the pedal bone suggesting a poor prognosis.

==References==

==References==