One foot ……three different types of laminitis…. type three- supporting limb laminitis (SLL) and traumatic laminitis Supporting limb laminitis happens as a secondary event to another leg being affected by a painful and/or traumatic injury. It often follows a fracture or severe synovial infection of joint infections, or ulcerations following lymph infection. Incidence of this type of laminitis is thought to be around 10%, it often depends of the severity of the lameness of the other leg and the level of primary infection. Mortality is around 50% as so many cases develop into ‘sinkers’. Because the primary source of lameness is in another leg SLL is often overlooked and owners of horses with very lame/hospitalised/fractured horses are advised to watch for the following signs… Examine the coronet band in the morning and again in the evening, in most healthy horses, it will sit flat against the hoof wall. Look out for a developing depression between the hoof wall and the skin at the coronary band which will indicate the coffin bone (P3) may be coming detached and sinking into the sole. Also look carefully at the skin around the hoof to see if it starts to sink and stretch, also indicating coffin bone movement; Monitor the sole for pain and normal growth A current area of research is using tissue microdialysis to monitor energy metabolism in the foot. This technique should be able to spot changes in local blood flow or lack of, this would be especially useful for horses with SLL as they are unable to shift their weight from limb to limb which significantly increases the risks of compromised blood flow. Supporting limb laminitis The pathogenesis of supporting limb laminitis (SLL) is also unique among the various forms of laminitis. While a limb is heavily loaded, there is no filling of any artery below the coronary band. When the limb is persistently loaded in this way, such as occurs in horses at risk for SLL, lamellar ischemia presumably ensues. Lamellar bioenergetics are currently being investigated in an effort to further elucidate the pathophysiology of SLL In a recent UK study of the medical records of 113 horses Medical treated with half limb, full limb or transfixation pin casts at an equine referral hospital from 2000 to 2009 , 14 (12%) developed confirmed support limb laminitis. The bodyweight of the horse and duration of casting in weeks were significantly associated with support limb laminitis. Horses requiring full limb casts or transfixation pin casts were more likely to develop this complication than horses requiring half limb casts. Invest in a set of pillow wrap bandages as supports to all 4 legs in the event of a long term injury. Traumatic laminitis caused by concussion was the most common type of the disease when horses were used for transport and travelled long distances. More recently it has been discovered in feral horses from arid and semi-arid regions of the Australian outback, particularly those living in hard, rocky terrain and traveling great distances for forage and water. Depending on the type of ground surface and distances travelled, the incidence of chronic laminitis in these populations ranged from 40% to 93%, with the highest rates being reported for the horses in the harshest terrain. In all but one of the horses, whose changes were considered severe, the laminitis was categorized as mild or moderate. The most common histopathologic features were very thin SELs inner hoof wall, multi-branched SELs, and weakening and degeneration of the PEL. Radiographic features included an increase in the “sinker distance” (vertical distance from the proximal margin of the dorsal hoof wall to the top of the extensor process of P3), an increase in the distance between the external hoof wall and coffin or pedal bone, and side bone. This type of laminitis is viewed as overuse injury of P3 due to concussion and failure of the lamellar suspensory apparatus.
Posted on: Tue, 09 Sep 2014 09:47:00 +0000
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