The patency and contractility of the lymphatic channel which form the lymphatic system maintain a flow of approximately 2- 2.5 liters of lymph fluid per day. The electrolytes and the water from the lymphatic fluid will be absorbed by the lymph nodes.
Lymphedema most commonly affects the lower limb in 80% of the cases. Besides that lymphedema may also present in the upper limb regions. lymphedema is caused by accumulation of tissue fluid/lymph in the extracellular compartment/ interstitial space as a result of defective of lymphatic drainage to transport the fluid via lymphatic nodes and lymphatic vessels. Edema is another condition which is different from lymphedema. Edema is an accumulation of tissue fluid which the causes still remain unknown. Edema may associated with nutritional , renal or cardiac problems and lymphatic abnormality has not been confirmed. Besides that, lymphedema is rich in protein while edema of the kidney or heart failure has low protein content.
Lymphedema may be divided into primary lymphedema and secondary lymphedema. Primary lymphedema is associated with failure of the lymphatic system and the causes remain unknowns. Primary lymphedema initially appear to be pitted in nature and later progress to non pitting lymphedema. Primary lymphedema is usually unilateral .Primary lymphedema is associated with Milroy disease. Milroy disease is an autosomal dominant disorder. It is caused by mutation of the chromosome 5 which coded for vascular endothelial growth factor receptor. Milroy disease is a congenital disorder . Milory disease may present with aplasia of the lymph trunk . 3% of primary lymphedema is associated with Milroy disease. Other congenital disorder that may be associated with primary lymphedema may include distal obliteration, incompetence and dilation of the lymphatics. Proximal obstruction, mega lymphatic and hyperplasia may also cause primary lymphedema.
Secondary lymphedema occurs due to destruction and obstruction of the lymph nodes. ( Lymphatic system failure ). The common causes of secondary lymphedema may include neoplastic infiltration of secondary carcinoma or non Hodgkin or Hodgkin lymphoma to the lymph glands. Iatrogenic causes may also lead to secondary lymphedema. It includes the irradiation of the lymph gland which leads to production of fibrous tissue blockage that cannot be transgressed by the lymphatic pathway. Surgical excision of the regional lymph node will also lead to the formation of the secondary lymphedema. This may include the surgical resection of the regional lymphatics that are performed as part of the treatment protocol in breast cancer. The procedure is performed to due to regional lymph node infiltration. Exposure to silica may also cause secondary lymphedema . This ore which is found in the soil may enter the lymphatic channel through the bare foot and causing the inguinal node to be blocked.
Infection may also cause secondary lymphedema. It may include filariasis. Filariasis is caused by an infection /infestation with Wuchereria Bancrofti. The infestation may later lead to the formation of the elephantiasis which is a common tropical disease. Other infection such as lymphogranuloma inguinale which is a recurrent non specific infection may also cause of secondary lymphedema.
There are a few disorders which cause the formation of edema which is not part of lymphedema. The disorders may include ilia venous obstruction, post thrombotic syndrome, Klippel - Tunnel syndrome, extrinsic pressure (pregnancy, fibrosis, retroperitoneal and tumor), hereditary angio edema, cardiac failure, idiopathic cyclical edema, allergic disorders, hypoproteinemia, hepatic failure, renal failure, gigantism, fat , disuse (wheelcahir bound), lipodystrophy, lipo edema and AV malformation.
In terms of epidemiology, the primary lymphedema is uncommon. Its 2- 3 times more common in female. The annual incidence is around 1 in 6000. The secondary lymphedema is more common than primary lymphedema. Filariasis is the most common causes of lymphedema worldwide.
The pathology of lymphedema may be divided into the pathology of primary lymphedema and the pathology of secondary lymphedema. The primary lymphedema occurs due to congenital abnormality of the development of the lymphatic system.This is proved by the present of lymphatic channel hyperplasia, hypoplasia, aplasia or dilation of the lymphatic channel that affects the lower limbs.Secondary lymphedema is caused by obstruction and destruction of the lymphatic channel by known causes such as filriasis, malignancy, radiotherapy and surgery.Initially the swelling appears as an episodes of infective cellulitis or a result of minor trauma. The lymphedema is pitting in characteristic however in later stage it becomes non pitting. In filariasis the worms will enter the lymphatic system and initiated a fibrotic inflammatory reaction which leads to non-pitting edema.
In terms of age, primary lymphedema may present in young adults or at birth and in some cases it involves the young adult. People undergo treatment for cancer or old and middle age individuals are more prone to develop secondary lymphedema. In term of family history , many causes of primary lymphedema ( Milroy disease) are familial and few abnormalities in the gene has been identified.
The female is more prone to develop lymphedema than male in both primary and secondary lymphedema. Female cancer patient tends to develop lymphedema because of the breast carcinoma able to spread to the axillary lymph nodes or the metastasizes of the tumor of the ovary and uterus in the iliac lymph glands.
The most common cause of lymphedema is filariasis. It is the most common disorder in tropical and non tropical countries which is caused by infestation of the parasites Wuchereria bancrofti. Filariasis is also associated with elephantiasis.
The patient may also present with the swelling of the upper and lower limbs. The swelling is worst most commonly towards the end of the day. Primary lymphedema mostly affects the lower limb. It may be started from a case of trivial injury or sprain of the ankle. The swelling is bilateral and may take years to develop. The secondary lymphedema is associated with swelling that appear in a few weeks and progress rapidly later.
The patient does not complain of any painful sensation on the sites of swelling. The patient however may suffer from discomfort due to mechanical disability or increase in the weight. Patient with lymphedema may also initially present with rigors , sweating and malaise. This will later proceed to swelling, redness and tenderness of the limb. This condition is known as acute cellulitis which is an episode of infection that get through the crack between the toe caused by athlete's foot ( tinea pedis). Clear and colorless fluid will be leaking from a vesicle that is present on the skin.
Toe is the most common sites that are affected by lymphedema of the lower limb. The toe may be squashed together and become square in shape and cross section. Thick scale sometimes may grow outward and form wart like structure. Lymphedema may be complicated with hyperkeratosis and secondary thickening of the skin. These conditions may lead to an inability to pinch the skin together at the dorsal surface of the second toe . This condition is known as Stemmer sign.
Lymphedema that is associated with mega lymphatic may present with chylous ascites, chylothorax and leak from the skin vesicles. Skin edema may initially be pitting . The longer duration of lymphedema may lead to the skin become non - pitting, browny and fibrotic with the weeping from the vesicles. There is a loss in the ankle contour and condylomas/thickened skin areas may present.
The patient who suffer from primary lymphedema may present with slightly enlarged and thickened lymph glands. The lymph glands will be hard in case of infiltration with primary and secondary tumors. The area which is drained by the palpable lymph gland should be examined. A full examination should be carried out to look for any possible causes of secondary lymphedema.
The investigation may include blood test, isotopes lymphoscintigraphy, contrast lymphangiography, duplex ultrasonography, X ray lymphangiography, CT scans, MRI scans, lymph node and tissue biopsy.
The blood test may include full blood count to detect the present of eosinophilia, ESR, liver function test and urea and electrolytes.
Isotopes lymphoscintigraphy will usually show the level of obstruction and confirm the diagnosis by injection of 99mTc- labelled colloid subcutaneously into the first web space of the foot and gamma counter is used to measure the movement of the isotopes. Contrast lymphangiography is now rarely performed. Duplex ultrasonography is useful to exclude any vascular compromise and causes of swelling. If surgery is planned X ray lymphangiography is performed. CT scan and MRI scan may point out the sites of obstruction.
The management may include conservative, medical and surgical approach. First / initial approaches may include exclusion of other causes of edema. Foot hygiene /skin or foot care is important to prevent the development of splits in the interdigital clefts which is the sites of entry of infection. Besides that skin and foot care is also important to prevent fungal infection. Any case of fungal infection such as tinea pedis should be treated with lamisil. Elevation of the affected areas or limbs or exercise is also suggested. Compression with graduated compressing stocking or bandaging is also advisable. Regular massaging is also important in patients that present with mild to moderate lymphedema. Pneumatic massage devices are also available to regulate the massage procedure. It is important not to perform any venesection or blood pressure measurement on the affected sites.
Medical treatment should include the prescription of the antibiotic in patients who suffer from recurrent bout of cellulitis. Anti fungal treatment is considered in cases of tinea pedis. Diuretics are not given due to its non beneficial effect.
Surgical procedure is beneficial in 2%-5% of patient from gross swelling. The surgical procedure may include lymphatic ligation to abolish reflux, bypass procedure and reducing operations. Surgery for lymphedema is performed in case there is a failure of the medical and conservative treatment. It should be carried out before obliteration of the distal lymphatics. Surgical procedure carries a poor outcome.
The surgical procedure may include Bridge operation, Charles operation and Homan operation. Bridge operation involved bypassing an obstructed iliac lymphatics from the bisected part of the inguinal nodes to an isolated pedicles of the small bowel.
Charles operation is a debulking operation. It involves excision of the subcutaneous tissue and it is followed by application of the skin graft to the exposed fascia. Homan procedure is another variant of debulking operation. It involves the removal of the wedges of tissue from the affected limb and heal with primary closure.
The complication of lymphedema may include ulceration, reduced mobility, pain related to tissue swelling, poor cosmetic appearance and increase in protein and fluid which make the skin prone to cellulitis.
Primary lymphedema has a good prognosis and response to conservative management. The prognosis of secondary lymphedema depends on the etiology.
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