Chronic progressive lymphoedema
|
Chronic progressive lymphoedema is a specific lymphostatic disease which has been found in several heavily feathered breeds - the Shire, Clydesdale, Belgian Draft and Gypsy Cob. Recently a similar condition has been noted in Friesians.
CPL was first identified at the UCDavis School of Veterinary Medicine. It was originally thought to be a 'therapy resistant' pastern dermatitis, until it was realised that these infections and infestations were secondary to an underlying lymphoedema. It is important to realise that the pastern dermatitis does not cause the lymphoedema, but can further damage the already fragile skin which results from lymphoedema.
CPL is described in detail on the UCDavis website, and the degree to which it develops varies greatly between horses. It starts at an early age and progresses throughout the horses life, and in evere cases can end in disfigurement and disability in the legs comparable to the most severe stage of human lymphoedema.
|
The first symptom, a soft 'pitting' oedema, is difficult to detect under the heavy feather and usually goes unnoticed, followed by the development of firm, fibrotic folds of tissue in the rear of the pastern. The presentation of CPL varies, but firm folds up the back of the lower leg and nodules between the coronet and knee/hock appear.
(Picture: early folds, clipped leg, Gypsy Cob)(M Way).
|
|
With time these can become extremely hard. The limb volume can dramatically increase and the skin may crack and a protein rich fluid seep out, which is caustic and very attractive to bacteria. The nodules may interfere with movement and damage underlying structures such as tendons and ligaments. Lymphangitis may develop.
 |
Clipping the feather is very helpful, and scrupulous attention must be paid to avoiding secondary infections and other causes of inflammation, but it is crucial to remember that CPL is not 'just' pastern dermatitis, and that the underlying lymphostatic disease will still be present no matter how well pastern dermatitis is controlled.
As always with lymphoedema, skin care must be gentle and avoid irritating the skin. Please see under 'Conditions, Lymphoedema' and 'Equine Lymphoedema Complex' for more information.
|
Fibrotic nodules deform leg
Research has shown that horses with CPL have altered elastin, a substance essential for the function of their lymphatic system. It is a congenital 'primary' lymphoedema and possibly hereditary. A significant amount of interbreeding within/between the affected breeds has been observed and further research is in progress to try to identify a genetic marker so that horses with the condition can be identified before symptoms appear, and not used for breeding.
However this may cause a dilemma for some breeders. CPL was initially thought to be rare but is now identified in many horses, and if hereditary may be more severe in some bloodlines than others. Also, some of the breeds almost died out in the last century and are still considered 'at risk'. This may contribute to current contention within some breed fraternities over whether CPL exists, with some breeders and owners unwilling to accept this, despite the scientific evidence, whilst others have expressed great concern about the condition and are keen to do everything they can to eradicate it.
A small trial which we undertook at UCDavis Centre for Equine Health has shown that EMLD can be used successfully to manage Chronic Progressive Lymphoedema, and results are published in the Equine Veterinary Education Journal, Feb. 2012. Details can be found at:
Powell, H. and Affolter, V. K. (2012), Combined decongestive therapy including equine manual lymph drainage to assist management of chronic progressive lymphoedema in draught horses. Equine Veterinary Education, 24: 81–89. doi: 10.1111/j.2042-3292.2011.00311.x
|