Elephantiasis is a condition characterized by gross enlargement of an area of the body, especially the limbs. Other areas commonly affected include the external genitals. Elephantiasis is caused by obstruction of the lymphatic system, which results in the accumulation of a fluid called lymph in the affected areas.
Functioning as part of the immune system, the lymphatic system helps to protect the body against infection and disease. It consists of a network of tubular channels (lymph vessels) that drain a thin watery fluid known as lymph from different areas of the body into the bloodstream. Obstruction of these vessels results in the massive swelling and gross enlargement characteristic of elephantiasis.
In areas where filariasis is endemic, the most common cause of elephantiasis is a parasitic disease known as lymphatic filariasis and, in the medical literature, the terms lymphatic filariasis and elephantiasis may be used interchangeably. Elephantiasis due to lymphatic filariasis may also be referred to as "true" elephantiasis. In most areas, the lymphatic damage associated with elephantiasis has other causes including certain sexually transmitted diseases (e.g., lymphogranuloma venereum); tuberculosis; an infectious disease called leishmaniasis; repeated streptococcal infections; leprosy; and environmental factors such as exposure to certain minerals (e.g., silica). In some cases, no cause can be identified (idiopathic).
Recently a team of researchers funded by the National Institute of Allergy and Infectious Diseases (NIAID), one of the National Institutes of Health (NIH), has recently revealed the genetic secrets of one of these parasites. The researchers report solving the complete genome of Brugia malayi, one of the worms that causes the often debilitating disease elephantiasis.
The main symptom of elephantiasis is gross enlargement and swelling of an area of the body because of the accumulation of fluid. The arms and legs are the areas most often affected. An entire arm or leg may swell to several times its normal size resembling the thick, round appearance of an elephant’s leg. The skin of the affected areas usually develops a dry, thickened, pebbly appearance and may become ulcerated, pitted and darkened (hyperkeratosis). Fever, chills, and a general feeling of ill health (malaise) may also be present.
Elephantiasis may also affect the male and female external genital organs. In a male, there may be enlargement of the scrotum, and the penis may be retracted under skin which has become thickened, nonelastic, hot and painful. The spermatic cords may thicken. Affected individuals may experience pain and a burning sensation.
The external parts of the female genital organs (vulva) may also be affected by elephantiasis. A tumorous mass covered by thickened and ulcerated skin may develop between the thighs and may be accompanied by enlarged lymph nodes (lymphadenopathy) of the legs. In some women the breasts may become enlarged.
Underlying damage to the lymphatic system may leave individuals susceptible to secondary bacterial and fungal infections that can greatly worsen the condition. Although the legs, arms and external genitalia are most often affected, elephantiasis can affect any area of the body.
Elephantiasis is caused by obstruction of the lymph vessels of the lymphatic system. As lymph moves through the lymphatic system, it is filtered by a network of small structures known as lymph nodes that help to remove microorganisms (e.g., viruses, bacteria, etc.) and other foreign bodies. Groups of lymph nodes are located throughout the body, including in the neck, under the arms (axillae), at the elbows, and in the chest, abdomen, and groin. In addition to the lymph nodes, the lymphatic system includes the spleen, which filters worn-out red blood cells and produces lymphocytes, and the tonsils, which are masses of lymphoid tissue in the throat region that help to fight infection. Lymphatic tissues also include the thymus, a relatively small organ behind the breastbone that is thought to play an important role in the immune system until puberty, as well as the bone marrow, which is the spongy tissue inside the cavities of bones that manufactures blood cells. Lymphatic tissue may also be located in other regions of the body, such as the skin, small intestine, liver, and other organs.
In underdeveloped regions of South America, Central Africa, Asia, the Pacific Islands and the Caribbean, obstruction can be caused by a parasitic disease known as lymphatic filariasis. Lymphatic filariasis is caused by three different species of worms known as Brugia malayi, Brugia timori and Wuchereria bancrofti. These worms cause damage and inflammation to the lymphatic system. The larval form of the worms is introduced into the human body through the bite of infected mosquitoes.
Genital elephantiasis can also be caused by bacterial sexually transmitted diseases, specifically lymphogranuloma venereum (LGV) and donovanosis. The bacterium that results in LGV, Chlamydia trachomatis serovar L1-L3, damages the lympathic system resulting in lymphatic obstruction in the genitals. Chronic obstruction eventually results in genital elephantiasis. Donovanosis is caused by the bacterium Calymmatobacterium (Klebsiella) granulomatosis. Donovanosis causes genital elephantiasis because the body’s immune system response to the bacterium causes inflammation and narrowing (constriction) of the lymphatic vessels.
Elephantiasis is also associated with a disorder known as podoconiosis. Podoconiosis, sometimes referred to as nonfilarial elephantiasis, is a disorder caused by the absorption of minute mineral particles from the soil through the feet of barefoot individuals. It is believed that the mineral particles cause an immune system response eventually resulting in the formation of inflammatory masses of nodules (granulomas) in the lymph vessels of the feet and legs.
Additional causes of elephantiasis include a protozoan disease called leishmaniasis, tuberculosis, leprosy, and a repeated streptococcal infection. Elephantiasis may also occur secondary to trauma, surgery or radiation. For example, treatment such as the surgical removal of lymph nodes to treat cancer may result in the accumulation of lymph and subsequent swelling (lymphedema).
Elephantiasis occurs with the greatest frequency in tropical regions including Southeast Asia, India, Africa and South America as a manifestation of lymphatic filariasis.
Elephantiasis due to other causes is rare. Elephantiasis can affect men or women of any age.
A diagnosis of elephantiasis is made based upon a thorough clinical evaluation, a detailed patient history and identification of characteristic symptoms. A variety of tests may be used to determine the underlying cause of lymphatic damage and subsequent elephantiasis.
Treatment of elephantiasis usually involves treating the underlying condition. Lymphatic filariasis is treated with diethylcarbamazine. LGV is treated with doxycycline. Donovanosis may be treated with azithromycin.
However, in many cases, medical therapy alone is not enough and surgery may be necessary. In cases where the male genitals have been affected, reconstructive surgery on the penis and scrotum has been successful. Anti-streptococcal antibiotics are used to relieve secondary infection. Lymphatic tissue may be removed by surgery or radiation therapy.
Other treatment is symptomatic and supportive.
A team of researchers funded by the National Institute of Allergy and Infectious Diseases (NIAID), one of the National Institutes of Health (NIH), has recently revealed the genetic secrets of one of these parasites. The researchers report solving the complete genome of Brugia malayi, one of the worms that causes the often debilitating disease elephantiasis.
The B. malayi genome reveals dozens of potential new targets for drugs or vaccines and should provide new opportunities for understanding, treating and preventing elephantiasis and similar diseases.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
For information about clinical trials sponsored by private sources, contact:
Kasper, DL, Fauci AS, Longo DL, et al. Eds. Harrison’s Principles of Internal Medicine.
16th ed. McGraw-Hill Companies. New York, NY; 2005:12-4.
Bennett JC, Plum F., eds. Cecil Textbook of Medicine. 20th ed. Philadelphia, PA: W.B. Saunders Co; 1996:1939-42.
Gupta S, Ajith C, Kanwar AJ, et al., Genital elephantiasis and sexually transmitted infections – revisited. Int J STD AIDS. 2006;17:157-65.
Fuller LC. Podoconiosis: endemic nonfilarial elephantiasis. Curr Opin Infect Dis. 2005;18:119-22.
Bouya PA, Lomina D. Scrotal elephantiasis: about seven operated cases. Bull Soc Pathol Extol. 2004;97:315-7.
Hornberger BJ, Elmore JM, Roehrborn G. Idiopathic scrotal elephantiasis. Urology. 2005;65:389.
Frommel D, Ayranci B, Pfeifer HR, et al., Podoconiosis in the Ethiopian Rift Valley. Role of beryllium and zirconium. Trop Geogr Med. 1993;45:165-7.
FROM THE INTERNET
Elephantiasis. The Columbia Encyclopedia, Sixth Edition. Copyright. 2001-05. Available at: http://www.bartleby.com/65/el/elphntia.html Accessed on: May 29, 2006.
General Practice Notebook. Elephantiasis. 2003. Available at: http://www.gpnotebook.co.uk/cache/1516961822.htm Accessed On: May 29, 2006