[Concept]
Lymphedema is an edema caused by the retention of lymphatic fluid in a part of the body due to a defect in the lymphatic system. Long-term lymphedema is prolonged due to the change of local subcutaneous fatty tissue into fibrous connective tissue, keratinization and thickening of the skin, and even the appearance of elephantiasis.
[Diagnosis]
1. Clinically, the course of the disease can be divided into 3 stages: stage 1 is concave edema, which can be basically relieved by elevating the limb; stage 2 is non-concave edema, which cannot be well reduced by elevating the limb; stage 3 is irreversible edema, which can even develop into recurrent infection, fibrosis and sclerosis of the skin and subcutaneous tissues, i.e., the common rubber leg stage. In some cases, milky lymphatic vessels with varicose lower limbs can be observed as the reflux of celiac disease.
2. Laboratory tests: In filariasis, an increase in eosinophils may be observed, and peripheral blood smears may show Bancroftian filariasis. Other laboratory tests are mostly non-specific.
3.Lymph nucleus visualization: The lymph nucleus isotope is injected into the distal part of the limb to observe the lymph nucleus isotope visualization of the limb, and the following conditions can be considered as lymph nucleus abnormalities: slow or even no clearing of the visualization at the injection location; diffuse or subcutaneous visualization of the visualization at the distal part of the limb; little or no visualization of the lymph nodes in the groin, axilla or main-iliac artery; abnormal visualization pathways.
4.Lymphadenography: Abnormalities of lymphatic vessels and lymph nodes may appear. Abnormalities of lymphatic vessels may be manifested as: thickening of lymphatic vessels, distortion, appearance of collateral circulation, or retention of contrast agent in lymphatic vessels after 24 hours; abnormalities of lymph nodes may be: enlargement, filling defect, destruction, reduction or disappearance of lymph nodes.
5.CT/MRI is used for the differential diagnosis of limb edema, and other causes of limb edema such as tumor and lipoedema can be detected.
[Differential diagnosis]
1. Differentiation of primary lymphedema and secondary lymphedema
Primary lymphedema refers to edema caused by congenital abnormalities of lymphatic vessels, such as dysplasia or hyperplasia of lymphatic vessels. It can also be divided into 2 categories, hereditary and sporadic, and the latter is seen. Hereditary lymphedema is usually seen in boys before the age of 1 year, with bilateral onset and a family history of the disease, and the edema usually includes all of the lower extremities. Sporadic lymphedema is most often seen in girls in their late teens and occurs unilaterally in the lower extremities, mostly involving only the lower knee.
Secondary lymphedema is mostly caused by surgery, trauma, infection, inflammation and tumor, etc. Filariasis is the most common type of lymphedema, which can eventually form a typical elephant skin leg.
2.Differentiation of lymphedema from other edema
Systemic edema: cardiogenic edema, mostly concussive edema at the ankles bilaterally, can appear as other findings of right heart failure, such as enlargement of the liver and positive hepatic jugular venous reflux sign. Nephrogenic edema, mostly edema of the eyelids in the early morning, and laboratory tests may reveal impairment of renal function. Hepatogenic edema, mostly abdominal enlargement due to ascites, can be detected on physical examination with signs of ascites and laboratory tests reveal significant impairment of liver function.
Venous edema: skin atrophy and hyperpigmentation, and ulceration of the limbs are more frequent, while lymphedema is mostly without tissue microcirculation disorders, without hyperpigmentation and ulceration. Ultrasound of the veins of the lower extremities may reveal reflux due to thrombosis of the deep veins or impairment of valve function.
Iliac compression syndrome: venography may reveal compression of the left iliac vein by the right common iliac artery
Lipoedema: occurs mostly in women with diffuse, symmetric, non-depressed increased subcutaneous tissue in the limbs. mri can help identify.
[Treatment]
1. Prophylactic treatment: mainly includes eradication of filariasis, aggressive treatment of infectious or rheumatic inflammation of the lower extremities, attention to protection of the axillary and inguinal lymph nodes and surrounding venous blood flow during radical surgery for malignant tumors (e.g. breast cancer, gynecological pelvic tumors, osteosarcoma of the lower extremities) and subsequent radiotherapy.
2. Drug therapy: Benzoprogesterone reduces the intercellular protein concentration by increasing the activity of mononuclear giant eosinophils, thus making the tissue edema decrease. Diuretics and local injections of cortisol hormone can work briefly, but the side effects of long-term use are more significant.
3.Physical therapy: For patients with early lymphedema, some physical therapy can be used to relieve limb tension, mainly including elevation of the affected limb, massage, bandages, functional exercise, pressure pumps and some physical therapy including heat therapy.
4.Surgical treatment: The majority of patients can be relieved by the above-mentioned conservative treatment, while about 10% of patients need surgery. The indications for surgery are functional impairment due to continuous increase in limb volume or recurrent lymphangitis, and the surgical method is mainly to remove the redundant edematous tissue under the flap in stages, which can be divided into 2-3 stages with an interval of 3 months. Postoperative drains are placed in the wound for more than 5 days, absolute rest is given for >1 week, and pressure bandages are given for 3 weeks. The improved procedure can bury part of the skin tissue of the flap as under the incision, that is, to form a subcutaneous flap, which has the advantage of facilitating the formation of lateral branches of lymphatic vessels.
5.Lymphangioplasty: including direct lymphangioplasty, i.e. lymphangiovenous anastomosis, or artificial lymphangioplasty; and indirect lymphangioplasty by increasing lymphangiopathic reflux, but the long-term effect is yet to be proved.
[Line of treatment]
The diagnosis of lymphedema should be considered after the patient presents with swollen limbs, after ultrasound, CT, MRI, and laboratory examination of heart, liver, and kidney functions, after excluding causes due to organ failure, venous edema, and tumors, and after combining his surgical history, family history, and history of filarial infection with the presence of typical tissue edema and skin keratinization on examination. Lymphatic nuclear imaging and lymphography can be performed for further clarification, and again the former is preferred as non-invasive.
Conservative treatment is preferred for lymphedema with a clear diagnosis, and if it is ineffective, or if there is a huge limb with functional impairment, surgery is considered, with staged decongestion being the preferred surgical approach.