Diagnosis: Lymphedema secondary to obesity and vascular impairment

Lymphedema is the clinical manifestation of subcutaneous accumulations of protein-rich interstitial fluid (lymph stasis) resulting from an acquired obstruction or infiltration of the lymphatic system. Progressive, chronic, and deforming, lymphedema is both physically and psychologically debilitating.

The three primary categories of genetic lymphedema arecongenital lymphedema (Milroy disease), lymphedema praecox (Meige disease), and lymphedema tarda. Causes include innate valvular incompetence and congenital hypoplasia or aplasia of the peripheral lymphatics.

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Acquired lymphedema can be due to infection, congestive heart failure, vascular impairment, portal hypertension, renal dysfunction, obesity, trauma, radiation, or surgery. While the underlying etiologies of secondary lymphedema vary, clinical progression is similar and difficult to control.

Lymphedema most commonly affects the extremities, but it can involve the face, genitalia, or trunk. Recurrent attacks of lymphangitis (one key type of which is cellulitis) are a common pathophysiologic cause. Worldwide, the most common cause of acquired lymphedema is filariasis, obstruction of the leg’s lymphatic vessels by the parasite Wuchereria bancrofti. Lymphedema commonly occurs in developing countries, particularly in south Asia, and results in permanent lymphedema of the limb. Chronic lymphedema causes epidermal fissuring and impairment that allows bacteria to enter and grow.

The earliest symptom is nontender pitting edema, usually in the shins, followed by centripetal advancement. Edematous areas are frequently marked by erythema and thickening of the skin, which has a peau d’orange or woody edema appearance. Superinfection of broken skin can result in yellow crusts. Palpation can evoke a positive Stemmer sign (inability to pinch the dorsal aspect of skin between the first and second toes).

The differential diagnosis of lymphedema of unknown duration includes cellulitis, erysipelas, active filariasis, lymphangioma, pretibial myxedema, thrombophlebitis, edema related to hypoalbuminemia, renal and/or congestive heart failure, squamous cell carcinoma arising in lymphedema, and lymphedemalike Kaposi’s sarcoma. Acute-onset lymphedema likely has an acute infectious etiology.

Skin biopsy can help diagnose pretibial myxedema and is mandatory in areas of chronic ulceration to rule out malignancy. Liver function, blood urea nitrogen/creatinine levels, and urinalysis will identify a renal or hepatic source. A complete blood count with differential may reveal infection. Worms cause an extremely high eosinophil count. Lymphoscintigraphy, the gold standard, allows detailed visualization of the lymphatic channels and assesses areas of obstructed lymph flow, with minimal risk. Ultrasonography can identify changes in the lymphatic and venous systems and exclude venous abnormalities, e.g., deep venous thrombosis. MRI and CT detect neoplasms causing lymphatic obstruction, such as Kaposi’s sarcoma.

Treatment must begin as soon as lymphedema is suspected. First-line treatment involves physical therapy and compression hose. Physical therapy is geared toward producing manual lymphatic drainage through massage and exercise. Leg muscles must be strengthened, as this enhances venous return. Compression stockings (producing pressure >30-40 mm Hg), Unna boots, multilayer bandaging, and pneumatic pumps have been advocated. Leg elevation is essential. Maintenance of skin barrier function and debridement can be helpful. Natural skin moisturizers, such as urea and lactic acid, are beneficial. Diuretics are ineffective. Inducing remission of an obstructing neoplasm can resolve the lymphedema.

Minimizing infectious insults can improve the morbidity associated with lymphedema. Tinea pedis and onychomycosis provide portals of entry for gram-positive bacteria; treat with itraconazole or terbinafine. In cases of recurrent cellulitis or lymphangitis, long-term antibiotic therapy with such agents as penicillins or cephalosporins or with topical agents has been reported to yield some positive results. Filariasis is treated with diethylcarbamazine and albendazole.

Surgery is seldomly used and more seldomly effective. Approaches include drainage of lymph from the subcutaneous tissue to radical excision of the subcutaneous tissue with primary or staged skin grafting to total superficial lymphangiectomy.

Our patient’s lymphedema did not respond to physical therapy and compression hose. He was lost to follow-up.

Dr. Scheinfeld is assistant clinical professor of dermatology at Columbia University in New York City, where he has a private practice.