Learn about equine lymphology in the lessons below. Find out how the lymphatic system works, what makes it stop working and how feather mites can trigger CPL. We also learn the differences between primary and secondary lymphoedema and why the term ‘Chronic Progressive Lymphoedema’ is something of a misnomer.
Important references for CPL specifically:-
- Session 2 Figures 1 – 5: Diagrams of the nodes, ILVs, collectors and lymphatic system.
- Session 3: Skin territories. This is important to know when treating CPL as most therapeutic services need to avoid directly working on the affected skin territories (territory 3 for front limbs and 7 for hind limbs), which are far more extensive than one might expect.
- Session 3 Paragraph 15-16: How scarring and feather mites can trigger CPL in the genetically pre-disposed horse.
- Session 4 Figures 1 – 3: Dissection showing lower leg lymph vessels, diagrams showing the deep drainage of the body and hind limb.
Equine Lymphology and the Treatment of CPL
Sadly, we are now learning that the Manual Lymphatic Drainage (MLD) component of Combined Decongestive Therapy (CDT) is not particularly helpful for horses with CPL due to the extent of the damage to the lymphatic system. So medically-correct compression is the only tool we have and even that is little help in the advanced stages.
“Of all the horse’s biomechanical systems, perhaps one that is least understood or looked at is the lymphatic system. Much of our current research on equine lymphology has been conducted at the Veterinary University at Hannover in Germany, where they have discovered significant differences between the equine lymphatic system and that of the humans, and this has profound implications on the way we need to look at and treat lymphatic problems as well as how we keep and manage horses on a daily basis.”Rebecka Blenntoft
Schools of Lymphology
⭕ Ice/cryotherapy including ice boots, wraps, gel
Ice can hasten the progression of the disease and must not be encouraged.
The application of ice or very cold temperatures impedes the ability of the lymphatic system to transport lymph. The vessels will not work effectively. It also shuts down the microcirculation of the arterioles and venules. When the leg is removed from ice water there is a massive “re-starting” of the microcirculation – the arterial blood supply opens up (imagine a dam opening) and oxygen/nutrient rich blood fills the interstitium. This is sometimes called “rebound swelling” and greatly increases the burden on the lymphatic system.
The makers of such ice products/therapies then take samples and claim that they have increased blood flow, oxygen and nutrients which can only be a good thing… right? Sadly not for horses with lymphatic disease because it is the circulatory and lymphatic systems that then have to take all of that flooding away. If we bear in mind how even the lymphatics of healthy horses are compromised when standing still, then its not hard to see how horses with CPL (already struggling with overloaded, inadequate lymphatics) will fare.
Exposure to heat, including hot water and direct sun is also suspected to affect the rebound process described above and can cause discomfort.
It seems counter-intuitive but any therapy or product that increases blood flow to the affected area is strongly contraindicated. You can read why in the first point about Ice Therapies and the rebound effect.
“If someone is trying to sell you a product that they claim will help with CPL, ask them how it works. If it increases circulation/blood flow/arterial filtrate to the legs then it’s a no. They may maintain that it has helped CPL patients, in which case you can ask them this: “What parameters are you using to measure how it has helped over time?” To give a commentary on improvement of lymphatics, they need to be educated on equine lymphology and should therefore be able to advise on their monitoring methods. Don’t forget, that often a rapid reduction in limb size using contraindicated therapies could come back to bite you further down the line with decreased tissue quality and increased non-pitting oedema.“Rebecka Blenntoft
Piercing or cutting the skin can lead to infection and exacerbation of the lymphoedema.
⭕ Obesity/being overweight/mares in foal
Simply puts too much strain on the struggling lymphatic system, increasing the risk of infection and poor wound healing. As such, obesity or pregnancy should be considered potential triggers for CPL or a cause of flare ups in the already established disease.