If a patient has a gross generalized swelling of his leg, arm, or scrotum, or if a woman has a similar swelling of her breast or vulva, the condition is known as elephantiasis. Usually, this is due to long standing lymphatic obstruction. Occasionally, it is due to venous obstruction, but this is seldom gross enough to need surgery. Distinguishing between lymphatic and venous obstruction can be difficult. Oedema due to lymphatic obstruction becomes solid quite rapidly, but early cases may show pitting. Oedema due to venous obstruction becomes solid late, and eventually reaches a stage where it fails to pit.
In most areas, the causes of lymphatic obstruction (lymphoedema), in decreasing order of frequency are: (1) Tuberculosis. (2) Repeated lymphangitis leading to incompetent valves, usually due to streptococci from wounds. (3) Malignant glands in the groin, or less often the axilla. (4) Kaposi's sarcoma. (5) Block dissection of the glands, usually for carcinoma. (6) Congenital lymphatic hypoplasia, or incompetent lymphatic valves (Milroy's disease). Other causes include chronic fungal infections, and lymphogranuloma inguinale.
Two important causes of lymphatic obstruction are restricted to certain endemic areas: (1) filariasis (commonly due to infection with W. bancrofti and less often to Brugia malayi, or Brugia timori.). (2) ''Podoconiosis' (also called non-filarial endemic elephantiasis). Filariasis is restricted by the prevalence of the insect vectors, and podoconiosis by particular characteristics of the soil. Filariasis may involve any of the parts of the body listed above, but usually the legs or scrotum, whereas podoconiosis only involves the legs.
''Mossy foot' is a term used to describe: (1) Commonly, a variety of podoconiosis in which the epithelial hyperplasia is extreme. (2) Rarely, other disease causing multiple excrescences on the feet, notably chromoblastomycosis. Elephantiasis due to advanced podoconiosis (whether it has reached the ''mossy foot' stage or not) responds fairly well to surgery. Elephantiasis due to filariasis is difficult to treat surgically. It is a popular misconception that filariasis is the commonest cause of lymphoedema; this is so only in filarial hyperendemic areas.
In practice, the exact diagnosis of the grosser forms of oedema leading to elephantiasis is not absolutely essential, because the practical methods of surgical treatment are similar in all of them[md]excision and grafting.
ELEPHANTIASIS This is the patient with gross enlargement of some part of his body.
LYMPHATIC OR VENOUS OBSTRUCTION? Lymphatic obstruction is much more likely.
Suggesting lymphatic obstruction[md]a slow onset, pitting except in late stages, when there is much secondary fibrosis, hyperkeratosis of the epidermis, which may be extreme (''mossy foot').
Suggesting venous obstruction[md]a rapid onset, some obvious cause for the obstruction, pitting on pressure, often ulceration of the skin, rarely gangrene.
INVESTIGATIONS. If he comes from an area where W. bancrofti is endemic, examine several nocturnal blood smears. There are no bone changes, so an X-ray is normal. Lymphangiograms are unlikely to be helpful.
THE DIFFERENTIAL DIAGNOSIS includes the common medical causes of peripheral oedema (heart failure, nephritis, and cirrhosis of the liver, etc.). In these the swelling is usually equal in both legs. In the surgical causes, particularly podoconiosis, it is usually unequal.
Suggesting bancroftian filariasis[md]scrotal involement, oedema which starts at the most dependent part for each site and moves upwards[md]below the malleoli for the leg, the fundus for the scrotum, the foreskin for the penis, and the dorsum of the hand for the arm. Elephantiasis of the scrotum with few changes in its skin.
Suggesting podoconiosis [md]a bare-footed patient from a podoconiosis area; worse on one leg than the other; below- knee swellings most marked distally. Symptoms are the first evidence of disease (in filariasis they are the last), and include burning of the lower legs at night, with persistent itching of the 1st and 2nd toe clefts, and plantar oedema of the forefoot. No filaria in the blood, and a chronic warty thickening of the lower legs (''mossy foot').
Suggesting chronic non-specific infection[md]some source for it, such as a tropical ulcer (if the swelling is in the lower leg). Acute recurrent attacks of lymphangitis. Enlargement of the nodes draining the swollen area only: these may be large and firm, or small and fibrotic. Lines of hyperpigmentation on the skin indicating previous lymphangitis (not easy to find, so look carefully; and seldom visible on a dark skin). A lymph node biopsy showing fibrosis and non-specific inflammatory changes.
Suggesting tuberculosis[md]chronic enlargement of many superficial nodes[md]inguinal, axillary, and cervical; a history of prolonged illness in the past, with fever and enlarged nodes, some of which discharged for long periods; multiple sinuses, or the scars that follow their healing. Lymphogranuloma also produces sinuses, but these are usually confined to the superior group of nodes, over the medial part of the inguinal ligament. Scars over the lower end of the vertical chain are more likely to be caused by tuberculosis. Involvement of an entire leg from toes to groin, or an entire arm or a woman's breast. A positive lymph node biopsy confirms the diagnosis; if tuberculosis is no longer active only non-specific fibrosis may be seen.
The site involved also influences the probable cause. Breast and arm, or vulva[md]tuberculosis. Scrotum[md]bancroftian filariasis. Lower leg[md]filariasis, podoconiosis.
CHEMOTHERAPY. If you are in doubt, try the appropriate specific treatment for tuberculosis or filariasis. Lymphoedema due to tuberculosis nearly always settles with chemotherapy, unless it is diagnosed very late. Antibiotics are unlikely to influence chronic non-specific inflammation.