What are the main causes of swollen legs?
One of the most common complaints in medicine is swollen legs. Swelling of the legs or “leg edema” is a manifestation of an underlying disease that needs to be found. Many pathologies can cause swollen legs, and in many patients, we can see multiple co-existing problems contributing to the development of edema, at the same time.
Having a simple but comprehensive framework to find your way through this convoluted path is necessary to avoid delayed diagnosis and prevent many unwarranted investigations.
The four main contributors to swollen legs are Venous Hypertension, Medications side effects, Lymphedema and Lipedema.
As the name implies, ‘Venous Hypertension’ refers to the raised pressures within the leg veins, which can be attributed to two leading causes:
- Chronic Venous Insufficiency (CVI)
- Venous flow obstruction and stasis
Chronic Venous Insufficiency (CVI)
CVI occurs when the veins in the legs cannot adequately pump blood back towards the heart. This can cause blood to pool in the veins, leading to swelling, pain, and skin changes in the affected area.
CVI can be caused by a variety of factors, including:
- Damage to the valves in the veins by various causes, including long hours of standing, obesity, smoking, trauma and prior clot in the veins or DVT (Deep Venous Thrombosis). This causes blood flow reversal in the veins – towards the periphery – which is called, Reflux.
- Weakness or damage to the veins’ walls can occur due to aging.
- Genetics, as some people may be more prone to CVI due to their family history.
Symptoms of CVI may include:
- Swelling in the legs or ankles.
- Pain or aching in the legs, especially after prolonged sitting or standing.
- Skin changes in the affected area, such as thickening and discolouration (Fig-1: Lipodermatosclerosis) , or the development of varicose veins.
Treatment for CVI may include:
- Compression therapy: Wearing compression stockings or bandages can help improve blood flow in the legs and reduce swelling.
- Medications: Medications such as diuretics or blood thinners may be prescribed to help manage symptoms.
- Endovenous ablation: a minimally invasive procedure that uses heat or lasers to seal off damaged veins and redirect blood flow to healthier veins.
- Lifestyle changes: such as losing weight, exercising regularly, and avoiding prolonged periods of sitting or standing, can help improve blood flow and prevent further damage to the veins.
Venous flow obstruction and stasis
Obstruction to blood flow in the venous system is mainly caused by venous blood clots (DVT) however there are other conditions in which compression of the larger veins – for example in the thigh or pelvic area – can cause pooling of the blood in the periphery. Examples of these conditions are tumours and pregnancy.
Another important and common cause of blood pooling in the periphery is Heart Failure (HF). Although HF does not cause an actual obstruction in the venous system, it causes “sluggishness” of the blood flow, which contributes to the pooling and stasis of fluid in the lower limbs. Another contributing factor that increases lower limb edema in HF is increased – ineffective – intravascular volume, which is a compensatory mechanism by kidneys to keep the vital organs perfused and oxygenated.
Lipo-dermatosclerosis is a condition that affects the skin and fat tissue in the lower legs. It is a type of panniculitis, a group of inflammatory disorders affecting the subcutaneous fat tissue. In lipo-dermatosclerosis, the fat tissue in the lower legs becomes inflamed and fibrotic, leading to the hardening and thickening of the skin. These changes will cause pain, swelling, and redness in the affected area. Over time, the skin may become discoloured (hyperpigmented) and develop a “woody” texture. The exact cause of lipo-dermatosclerosis is unknown, but it is believed to be related to problems with blood flow in the veins of the legs. It can be associated with CVI and blood pooling in the legs. Treatment for lipo-dermatosclerosis is mainly the treatments recommended for Chronic Venous Insufficiency, including:
- Compression therapy: Wearing compression stockings or bandages can improve leg blood flow and reduce swelling.
- Medications: Non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids may help reduce inflammation and pain.
- Surgery: In some cases, surgery may be necessary to repair damaged veins and improve leg blood flow.
- Lifestyle changes: Making lifestyle changes such as losing weight, regular exercise, and avoiding prolonged periods of sitting or standing can help improve blood flow and prevent further damage to the veins.
Various pathologies can involve the lymphatic system, leading to the accumulation of lymph in the interstitium and causing swelling and edema in affected organs. In developed countries, cancer and its treatments like chemotherapy, radiotherapy, and surgery are the leading cause of lymphedema. However, parasitic infections are the primary cause of this issue worldwide.
Lipedema is a chronic disorder characterized by an excessive and abnormal accumulation of fat in the legs, thighs, buttocks, and sometimes arms that occurs almost exclusively in women and is typically symmetrical. Lipedema can cause pain, tenderness, swelling, and bruising in the affected areas. It is often misdiagnosed as obesity or lymphedema, but it is a unique condition that requires specialized treatment. The cause of lipedema is not fully understood. Still, it is thought to have a genetic component, and hormonal factors may also play a role.