The lymphatic system is a network of tissues and organs that help rid the body of toxins, waste and other unwanted materials. The primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body. Lymph also picks up the body’s excess interstitial fluid and returns it to the bloodstream.
When the lymphatic system becomes clogged or blocked it can cause a buildup of fluid in the tissues known as lymphedema. This most commonly occurs when lymph nodes are damaged or removed due to cancer treatment. However, there are also several other causes that can lead the lymphatic system to become backed up and clogged.
What is the Lymphatic System?
The lymphatic system consists of lymphatic vessels, lymph nodes, spleen, thymus gland and bone marrow. Here are the key components and their functions:
– Lymphatic Vessels: A network of thin tubes that carry lymph fluid throughout the body. They are similar to veins and arteries but have thinner walls. The vessels branch deeper into tissues to drain lymph back to the circulatory system. There are also lymph capillaries that collect excess fluid from tissues.
– Lymph Nodes: Bean-shaped glands located along the lymphatic vessels that filter lymph. They contain white blood cells that remove viruses, bacteria and other foreign substances. There are hundreds of lymph nodes found throughout the body.
– Spleen: Located in the upper left part of the abdomen, it filters foreign substances and old red blood cells from the bloodstream. It contains lymphoid tissue that produces lymphocytes.
– Thymus: Located between the lungs and behind the sternum, the thymus plays a key role in development of immune cells called T lymphocytes or T cells.
– Bone Marrow: Found within bones, bone marrow contains the stem cells that produce lymphocytes including T cells and B cells. These white blood cells fight infection.
This network of organs works together to circulate lymph and defend the body against germs and illness. Disruption of the lymphatic system can impair immune function and cause a fluid buildup.
Causes of Lymphatic System Blockage
There are several ways in which the lymphatic system can become backed up, slow or clogged. Common causes include:
– Lymph Node Removal: This is the most common cause of lymphatic system obstruction. Lymph nodes may be surgically removed during treatment for cancers like breast cancer, melanoma, gynecologic cancer and others. This can disrupt normal lymph drainage routes.
– Radiation Therapy: Radiation used to treat cancer can cause scarring and damage to nearby lymph nodes and vessels. It essentially burns the pathways and prevents proper drainage.
– Tumors: Cancerous tumors can grow into lymph nodes and vessels, compressing them and obstructing flow. The tumor itself can also shed cells that clog up the lymph drainage.
– Infections: Bacterial infections of the lymphatic system (known as lymphangitis) can cause inflammation and blockage of vessels. Viruses may also infect and damage lymph nodes.
– Scar Tissue: Scarring from surgeries, burns, trauma or chronic infections can impair lymphatic flow and function if the scar tissue compresses vessels.
– Parasitic Infections: Parasitic diseases such as filariasis are caused by microscopic worms that live in the lymphatic system. This causes major vessel dilation and dysfunction.
– Genetic/Primary Lymphedema: Some babies are simply born with abnormal or poorly-functioning lymphatic vessels due to genetic mutations and developmental problems.
Anything that damages the microscopic lymph capillaries in skin and tissues can increase risk for lymphatic blockage and clogged areas. Swelling often occurs below site of obstruction as fluid accumulates.
Signs and Symptoms
When portions of the lymphatic system become blocked, typical symptoms include:
– Swelling (lymphedema): Most commonly seen in arms and legs, this is characterized by enlargement and edema in a limb. It may start distally and spread proximally as more vessels clog over time. Swelling is soft and pitting.
– Discomfort, aching, heaviness: The swollen limb often feels uncomfortable as it is overfilled with fluid, creating tension on the tissues. Mild discomfort to more severe pain may be present.
– Skin changes: The skin may appear stretched, tightened and shiny. Later on the affected area can develop a pebbly “orange peel” texture.
– Infections: Fluid-filled limbs are prone to bacterial and fungal infections. Repeated lymphangitis and cellulitis are common.
– Restricted mobility: As the limb swells, normal range of motion is impeded. Everyday activities may be inhibited.
– Fatigue: Poor lymph drainage allows toxins and waste to accumulate, causing malaise and fatigue. The overloaded lymphatic system cannot filter properly.
Other possible signs include leaking fluid through skin, thickened skin, and swollen genitalia in cases of pelvic/groin lymph node removal. Lymphedema of internal organs can impair their function as well.
Risk Factors
A number of factors can increase risk for developing lymphedema when the lymphatic system becomes overwhelmed and clogged:
– Cancer surgery/radiation: As noted, a major risk factor is surgical excision of lymph nodes during cancer treatment. Removal of many deep lymph nodes or full lymph node dissections leads to high risk. Axillary node removal for breast cancer is most common.
– Obesity: Being overweight or obese stresses the lymphatic system as it must handle higher lymph loads. Excess fat can also compress vessels.
– Infection history: Recurrent infections including lymphangitis, cellulitis, parasites, etc. can damage lymph drainage over time.
– Trauma: Injuries or scarring from significant burns or other trauma can impair lymphatic function.
– Family history: Some people inherit lymphatic abnormalities or prone lymph vessels that predispose them to problems.
– Inactivity: Lack of muscle contractions helps pump lymph through vessels. Lack of movement allows fluid accumulation.
While genetics plays a role, most impaired lymphatic drainage is acquired throughout life rather than inherited. It typically arises due to injury or external factors overwhelming a previously normal system.
Diagnosis
Doctors utilize several approaches when diagnosing lymphedema:
– Observation and physical exam: Swelling in an arm or leg may be apparent upon examination. Pressing into the tissue will leave an indentation that persists, unlike common edema which rebounds quicker. The swollen area may be detected along lymph drainage paths.
– Medical history: The individual will be asked about risk factors, surgeries, radiation, family history, trauma, and timeline of swelling onset and progression. Doctors assess overall health.
– Imaging tests: Doppler ultrasound can show blockage in lymph vessels and nodes. MRI or CT scans may also identify swollen nodes or abnormalities. Lymphoscintigraphy uses radioactive tracer injected into tissue to track lymph flow.
– Volume measurements of limbs: Special water displacement tests can precisely measure and compare limb volumes on each side of body.
– Lab tests: Bloodwork, urinalysis and other labs rule out organ dysfunction contributing to edema. They may identify infections implicating lymphangitis.
Tracking the pattern of swelling and listening closely to the person’s history helps distinguish lymphedema from other causes of limb/fluid swelling. Biopsies are not normally needed for diagnosis.
Complications
Some potential complications that can develop from chronic lymphedema include:
– Infections: Bacteria including Staph and Strep organisms can infect the compromised area leading to episodes of lymphangitis and cellulitis which may recur. Antibiotics are needed to treat active infection.
– Lymphedema distichiasis: A rare inherited disease causing lymphedema and double rows of eyelashes which irritate the eye. Can lead to corneal damage.
– Lymphangiosarcoma: A very rare cancer of the lymphatic vessels arising from chronic lymphedema, occurring in about 1% of these patients. It manifests as multiple discolored lesions/nodules.
– Cosmetic impairment: Significant limb enlargement and tissue changes can cause psychosocial distress regarding appearance.
– Decreased mobility: In advanced stages, severe limb swelling impairs normal range of motion and ability to perform daily tasks. Walking can become difficult.
– Loss of limb function: Fluid pressure on nerves and tissues can lead to weakness and loss of limb strength needed for movement. Fine motor skills are affected.
– Skin injury: Weeping and cracking skin increases infection risk. Small wounds can worsen into ulcers and open sores.
– Poor wound healing: Impaired lymphatic drainage prevents clearing of bacteria and proper healing after any type of cut, surgical incision or wound.
Regular monitoring, prompt treatment of infections, and good limb hygiene helps reduce complications and severity in chronic lymphedema.
Treatment
Treatment focuses on reducing limb size and discomfort, preventing progression, and lowering infection risk. Options may include:
– Compression bandages/garments: These elastic sleeves or stockings provide gradient pressure to help drain fluid from a limb and can be worn long-term. Bandages may be used initially to reduce size faster.
– Manual lymphatic drainage (MLD): Specialized light massage techniques stimulate flow in stagnant areas and divert fluid to functioning lymph vessels and nodes. A lymphedema therapist performs MLD.
– Exercise: Specific exercises and stretches improve lymph drainage. However, overexertion can worsen swelling so moderation is important.
– Elevation of limbs: Keeping the affected arm or leg raised above heart level utilizes gravity to drain excess fluid from the extremity.
– Good skin care: Moisturizing, avoidance of cuts/burns, and proper nail and callus care protect the vulnerable skin and prevent infection entry.
– Pneumatic compression pumps: These devices use inflatable chambers that inflate and deflate in a sequence to push fluid out of swollen tissues. Often used as adjunct therapy.
– Medications: Antibiotics are used acutely for infections. Some diuretics may provide modest edema reduction but are not very effective long-term.
– Surgery: Operations to repair or bypass damaged vessels or remove excess tissue are options in severe cases unresponsive to other treatments.
Treatment is most effective when started early at first onset of swelling. A combination approach is commonly used for optimal lymph drainage.
Prevention
Preventing lymphedema altogether is challenging but these strategies may help reduce risk:
– Avoiding injury/trauma to at-risk areas: This protects vulnerable lymph nodes and vessels from damage.
– Promptly treating infections: This prevents lymphangitis episodes that can impair drainage over time.
– Maintaining a healthy weight: Obesity is a controllable risk factor that stresses the lymphatic system.
– Performing regular exercise: Muscle movement assists lymphatic flow through compressions.
– Avoiding constrictions: Clothing, jewelry or objects that constrict limbs can compress local vessels.
– Seeking prompt treatment for cancer: Early detection and careful surgical techniques may better preserve lymph drainage. Radiation is planned to avoid lymph exposure.
Patients undergoing lymph node removal for cancer should be educated about lymphedema prevention and monitored by their oncology team for any signs of swelling.
Conclusion
The lymphatic system can certainly become clogged or blocked due to its vulnerabilities. Cancer treatments, infections, trauma, chronic swelling, or inherited abnormalities in vessel formation all contribute to an overwhelmed, high-traffic system. When lymph drainage pathways are damaged or removed, backward flow and leakage into tissues results in lymphedema.
While complete prevention is difficult, early detection, prompt treatment, and diligent self-care can control symptoms and improve outcomes. Advances in microsurgery, medications and compression garments continue to provide hope for treating lymphedema. With proper awareness and management, it does not have to severely impact quality of life.