Principal Body System: Lymphatic
Definition: Lymph, lymphatic vessels and structures or organs containing lymphatic tissue (large numbers of white cells called lymphocytes) such as the spleen, thymus gland and lymph nodes.
Function: Returns proteins and plasma to the cardiovascular system; transports fats from the GI tract to the cardiovascular system; filters body fluids; produces white blood cells, and protects against disease.
The lymphatic system is a major part of the immune defense system - it's the body's waste disposal system.
However, the lymphatics are probably right at the bottom of the list when it comes to being noticed - it's certainly one of the least remembered systems. Yet it's absolutely critical for health. Think of it as the body's waste disposal system - proper functioning of the lymphatic system is essential in order to properly eliminate waste. In essence the lymphatic system is the body's detoxification system, and without it working properly, the body will get very, very sick.
It has three functions: fluid recovery, immunity, and lipid absorption, lipids being essential molecules which make up the building blocks of the structure and function of living cells. It also rids blood of acidic and toxic waste, filtering the toxic matter into the body’s two major detox filtration organs, the liver and kidneys.
The whole lymphatic system resembles a second circulatory system alongside the blood circulatory system. It's connected together by a web of tiny (lymph collector) vessels under the skin transporting fluid (lymph) which carries proteins and lymphocytes (the body's army of white blood cell pathogen destroyers) to various tissues in the body for cleansing and sorting, to maintain a healthy, cleansing fluid-balance within the body. The lymph travels into larger, deeper vessels which eventually discharge into the blood stream.
The lymphatic system does not have a ‘pump’ like the circulatory system, where the heart creates a ‘beat’ to push/pump the blood around the body - it depends entirely upon movement of the body, which is why so many horses develop 'puffy leg syndrome' if stabled long-term. The lymphatic system has to work against gravity, so requires constant movement by the body and proper breathing in order to move lymph through the lymphatic vessels, and to pass it through the filters in the lymph nodes.
Approximately 70% of the horse’s body is water, which means that anything affecting this fluid balance can have a profound effect on the horse’s well being. If movement is limited or in the event of severe illness, toxins can build up and blockages (i.e. puffy legs) appear. If the skin breaks, infection can occur, and it's all the more difficult to treat as by now the immunity system overall will be significantly compromised.
Lymph is the clear watery fluid which contains white blood cells (lymphocytes, the body's killer army), with a small concentration of red blood cells and proteins. It circulates through body tissues via its system, collecting harmful materials for disposal, typically bad fats/bacteria and so on, filtering them out through the system and bathing cells in much needed nutrients and oxygen.
The lymph pathways include ‘lymph nodes’ which filter the lymph by removing toxins and releasing the lymph back into the tissues. Lymph nodes are the third essential player alongside the liver and kidneys in the body's overall filtration of toxins, and play a vital role in the immune defence system.
Why does lymphangitis affect horses?
Over millions of years the independent horse has evolved from a small, forest-living creature with padded feet, into a graceful, fast, flight athlete, standing on elongated single toes and spending most of its time in constant motion. This continual movement in the horse’s leg is vital for the transport of lymph - quite simply, if the horse doesn't move, neither does lymph.
Cue human involvement and today’s methods of horse management, as in keeping them stabled for long periods of time without significant turnout, and/or making heavy training demands upon them, and we're on a slippery slope of causing stagnant circulation of lymph in the lymphatic system.
What happens if the lymphatics get blocked?
Inflammation of the lymph vessels, aka lymphangitis, occurs if the lymphatic system is compromised. The lymph vessels become inflamed and blocked, and the legs swell because the system cannot remove fluid from these tissues quickly enough.
The lymphatic system within the horse’s lower legs is also especially vulnerable to damage from wounds and infection. Lymph vessels get damaged and can no longer drain lymph fluid from the affected area. This also means that the body cannot fight infection as well as it can with a healthy lymph system.
If swelling occurs, the limb can literally increase in size by 2-3 times. Yellow fluid may seep from the skin in several places and the horse will be in significant pain and unable to move properly. Infection in the affected area may also cause the body temperature to rise.
The initial pain and swelling usually respond rapidly once addressed, although the puffy effect may linger for many weeks. The not-so-great news is that once a horse has had the condition, lymphangitis is likely to recur, and the horse may suffer from puffy leg syndrome permanently. If your horse spends a lot of time in a stable or is relatively immobile, poor lymphatic circulation can cause further swelling in a previously affected limb, but this will tend to dissipate on exercise.
In a nutshell, movement is absolutely key to a healthy lymphatic system.
Hydrate - ensure your horse is drinking plenty of water - the lymph system requires a constant supply of fluid to keep it functioning at its best.
Massage - a great way to encourage natural drainage of the lymph from the tissue spaces in the body – studies show that it can increase the volume of lymph flow by up to 20 times, making it easier for the body to remove toxins.
Movement - critical to keeping the lymph system open and flowing. When the muscles move, they also help move and pump the lymph within its vessels, even at walk. Also, sweat is one of the major elimination routes of toxins - waste product is eliminated via the sweat glands, which is another reason why movement is so important.
Dry Brushing - helps increase circulation which helps to boost slower-than-average lymph systems.
Breathing – I know, stating the obvious really. However, comfortable breathing is really important, because sufficient movement of air through the lungs also helps move and pump fluid through the lymphatic system while providing it with fresh oxygen. Thus if your horse has respiratory issues, keep those airways open.
Feed Garlic – garlic is a powerful lymphatic cleanser - add it to feed for the first month of treatment, by which time the building blocks should be in place for a healing effect.
Stress – keep stress levels down – a happy, balanced system helps decongest the lymph system.
Pesticides & Processed Food - preservatives, pesticides, herbicides, and food additives like refined sugar, all put strain on the lymphatic system. Consuming chemically treated, highly-processed sugary and fatty foods simply creates an even larger workload for your lymph system and stops it from properly filtering toxins.
Prescription Drugs - Ultimately, prescription drugs carry toxic residue into the body which suppress the immune system.