Problems in the lymphatic system of horses

The lymphatic system of horses plays a key role in the immune system and is of great importance for the health of the horse. When the lymph nodes and lymphatic vessels are not functioning properly, fluid can start to accumulate. This can lead to conditions such as edema, swollen legs, or Chronic Progressive Lymphedema (CPL).

In a previous article you could read about what the lymphatic system is exactly. The lymphatic system has several important functions:

• Removing waste products from the body.
• Immune function: fighting infections.
• Maintaining fluid balance in the body.
• Nourishing tissues.
• Fighting bacteria and other harmful microorganisms.
• Filtering toxins.
• Removing dead and damaged cells.

If the lymphatic system in your horse is not functioning properly, for example due to damaged lymphatic vessels or inadequate drainage of lymphatic fluid, problems can arise. Swollen legs, CPL, poor immune function, fatigue, skin problems, and shortness of breath can all be related to impaired lymphatic function.

Vulnerable

The lymphatic system is vulnerable. The balance between the inflow and outflow of tissue fluid can be disrupted by factors such as injury or lack of movement. The lymphatic system of horses is not equipped to handle a lot of extra fluid drainage, it simply cannot cope with it. This means that injuries (resulting in excess lymphatic fluid), often lead to accumulations. Especially in the (long and thin) legs, you can quickly see swellings and edema.

CPL

One of the most well-known and visible conditions related to damage to the lymphatic system is Chronic Progressive Lymphedema (CPL). With CPL, a horse's lymphatic vessels function poorly and lymphatic fluid is not adequately drained. The result is swollen legs and eventually ridges and bumps on the leg. Infections and skin problems can develop in the folds and ridges, and horses can suffer significantly from CPL. It is chronic (persistent) and progressive (it gets worse over time). CPL mainly affects hardy horse breeds such as draft horses, Shires, Friesians, and tinkers. CPL is sometimes confused with pastern dermatitis, but pastern dermatitis is easier to treat. CPL, on the other hand, does not go away. The only thing you can do is to take good care of the wounds to prevent them from worsening quickly and give the horse plenty of (free) movement. Movement activates the lymphatic system and helps drain the fluid. The cause of CPL is likely partially genetic. Poorly functioning lymphatic vessels and abnormal elastin content in the skin of certain breeds seem to play a role. In addition to movement and wound care, good nutrition is important to manage CPL.

Einschuss

In einschuss, also known as elephantiasis, the lymphatic system is (temporarily) overloaded. Einschuss usually starts with a small wound on the leg, which quickly results in a large amount of fluid in that leg, fever, and lameness. When einschuss occurs, you should always call the vet for antibiotics and/or anti-inflammatory drugs. If you act in time, you can prevent most damage to the lymphatic system and hopefully prevent the affected leg from remaining swollen. If the leg has been swollen for a long time, lymphatic vessels can be damaged and fluid drainage in that leg can be permanently impaired. The horse will then always have a slightly swollen leg.

Poor immunity and recovery from injuries

Because the lymphatic system plays such an important role in the immune system, it is involved in all injuries, illnesses, and conditions. A properly functioning lymphatic system helps the body remove dead cells, bacteria, and toxins. For example, a horse with a tendon injury may benefit from lymphatic drainage, a gentle massage technique that helps keep the lymphatic fluid moving properly. Especially when stall rest is prescribed and limited movement is possible. But even regular, minor, muscle damage resulting from training can be processed more quickly by a horse if its lymphatic system functions properly. It will then experience less muscle soreness and stiffness and will show a better training effect because the lactic acid and other waste products produced during training are removed more quickly.

Vague symptoms?

Unfortunately, a problem in the lymphatic system does not always lead to such visible symptoms as a swollen leg. Impaired lymphatic function can also result in vague symptoms such as poor resistance, fatigue, or skin problems. It can be difficult to find the cause in these cases. For many 'vague symptoms', it can be a good idea to support your horse with a mild cleansing treatment with nettle. This plant cleanses the blood and also boosts the lymphatic system.