You are in: eMedicine Specialties > Urology > Infections and Related Inflammatory Conditions Hydrocele, FilarialArticle Last Updated: Dec 27, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Bradley Fields Schwartz, DO, FACS, Associate Professor of Urology, Director, Center for Laparoscopy and Endourology, Department of Surgery, Southern Illinois University School of Medicine Bradley Fields Schwartz is a member of the following medical societies: American College of Surgeons, American Urological Association, Association of Military Osteopathic Physicians and Surgeons, Endourological Society, Society of Laparoendoscopic Surgeons, and Society of University Urologists Coauthor(s): Joe Miller, MD, Staff Physician, Division of Urology, Southern Illinois University Affiliated Hospitals; Rizk El-Galley, MD, Director of Clinical Research, Assistant Professor, Department of Surgery, Division of Urology, University of Alabama Editors: Edmund S Sabanegh, MD, Assistant Professor of Urology, Uniformed Services of the Health Sciences; Chier, Section of Male Infertility, Glickman Urological Institute, Cleveland Clinic Foundation; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; J Stuart Wolf, Jr, MD, FACS, David A Bloom Professor of Urology, Director, Division of Minimally Invasive Urology, Department of Urology, University of Michigan Medical Center; Edward David Kim, MD, FACS, Professor of Surgery, Division of Urology, University of Tennessee Graduate School of Medicine; Consulting Staff, University of Tennessee Medical Center Author and Editor Disclosure Synonyms and related keywords: filarial hydrocele, scrotal lymphedema, filarial worms, filaria, filariae, Filaria bancrofti, F bancrofti, Wuchereria bancrofti, W bancrofti, Brugia malayi, B malayi, Filaria malaya, F malaya, Culex pipiens, C pipiens, parasitic disease, parasitemia, parasite infection, filariasis, mosquito bite, lymphatic filariasis, nematode, roundworm, round worm, lymphangiectasia, filarial infestation, scrotal filarial infestation, skin sclerosis, elephantiasis, tropical eosinophilia, eosinophilic interstitial pneumonitis, chyluria, bancroftian filariasis, acute filarial lymphangitis, AFL, filarial dance sign, FDS INTRODUCTIONSection 2 of 11
  Lymphatic filariasis is a parasitic disease caused by the nematodes Wuchereria bancrofti, Brugia malayi, and Brugia timori. The adult worms of the species W bancrofti have a predilection for the intrascrotal lymphatic vessels in hosts; thus, hydrocele is the most common manifestation of bancroftian filariasis. In endemic areas, filarial hydrocele is a major cause of disability and disfigurement, as well as a source of direct and indirect economic loss, social stigma, family discord, and sexual burden. History of the ProcedureFilariasis has been a known disease for thousands of years. The first documentation of this disease was found in Egyptian papyrus prior to 5000 BC. In 1900, Sir Ronald Ross, a scientist from the Liverpool School of Tropical Medicine, reported that lymphatic filariasis is transmitted through mosquito bites. In 1902, Sir Ross was awarded the Nobel Prize in medicine for his discovery that malaria is transmitted to humans through mosquito bites. ProblemAccording to World Health Organization (WHO) statistics, 1 billion people in more than 80 countries are at risk for infection with this parasite. More than 120 million people have been affected by the parasites, and more than 40 million of them are seriously incapacitated and disfigured as a result. One third of infected people live in FrequencyBancroftian filariasis is endemic in tropical regions throughout the world. In the The WHO estimates that more than 1.3 billion people in 83 countries and territories are at risk for microfilarial infection. More than 90% of the estimated 120 million infections are due to W bancrofti, of which 26.79 million cases are hydrocele. No racial predilection for filarial infection has been shown. The sexual prevalence of filarial infection varies by region, possibly because of variable exposure in cultural or employment patterns that result in contact with vector species of mosquito. All ages are susceptible to microfilarial infection. Clinical manifestation and acute presentations of lymphatic filariasis increase in prevalence with age. The prevalence of filarial hydrocele also increases with age. EtiologyEight main species of nematodes (roundworms) can cause filariasis; however, the most common is W bancrofti (100 X 0.3 mm), followed by Brugia organisms. The nematodes can live for several years in the lymphatic vessels and lymph nodes. The female worms produce microfilariae (200-300 µm), which circulate in the blood. The microfilariae infect biting Culex pipiens mosquitoes (less commonly Anopheles, Aedes, and Mansonella species). It then develops into the infective filariform larvae within 1-2 weeks. During subsequent bites by the mosquito, the larvae infect human hosts and migrate to the lymphatic tissues, where they develop into adult worms within a year. PathophysiologyHumans are the definitive host of W bancrofti. Numerous species of mosquitoes from the genera Anopheles, Culex, Aedes, and Mansonia serve as the intermediate host. In infected humans, the adult W bancrofti worms are most commonly found in periaortic, inguinal, and intrascrotal lymphatic tissue. The microfilariae produced by the female worms enter the bloodstream and are ingested by feeding mosquitoes. Once in the mosquito, the juvenile worms pass through 2 larval stages before development halts. Subsequent blood meals taken by the mosquitoes transmit the third-stage larvae into the human dermis. The juvenile worms then migrate to lymphatic tissue in the infected human, where maturation is completed. While the adult female worms can continue to produce microfilariae in the human host, the adult worm burden cannot increase in the absence of the intermediate host. In endemic areas, filarial infection begins in childhood and the adult worm burden increases upon repeated exposures. Acute presentations most commonly occur in the fourth or fifth decade of life. Death of the adult worm causes an inflammatory reaction that manifests as acute filarial lymphangitis (AFL). Granulomatous nodule formation and recurrent episodes of AFL impair lymphatic flow, which predisposes the host to secondary bacterial infections. Secondary bacterial infections result in fibrosis, lymphatic obstruction, and lymphedema. High-protein lymphedema causes further inflammation and tissue destruction. Once damage is sufficient to overwhelm the lymphatic system, chronic hydrocele results. Recent research has implicated the endosymbiotic bacteria Wolbachia as a possible trigger in the immune reaction following the death of adult worms.2, 3 Release of these obligate intracellular bacteria by the dead adult W bancrofti worm increases the host’s plasma levels of interleukin (IL)–6, IL-10, lipopolysaccharide-binding protein (LBP), and soluble tumor necrosis factor (TNF)–alpha receptors. The exact role of Wolbachia in lymphatic filariasis and the possibility of novel targets for prevention and treatment, including tetracycline antibiotics, have not been fully studied. ClinicalAlthough filarial infection in endemic areas is generally acquired in childhood, the disease may take years to manifest before being diagnosed clinically in early adulthood. Therefore, in endemic areas, up to 50% of the population (more commonly men) may have subclinical infection and may develop pathologic sequelae (although rare). This is characterized by the presence of thousands or millions of parasites in the blood. However, this small number of infections in endemic areas with pathologic changes accounts for the bulk of clinical disease. Many individuals with filarial infection develop fever due to immune reactions. Patients present with episodic fever associated with lymphangitis, lymphadenitis, funiculoepididymitis (ie, inflammation of the spermatic cord and epididymis), transient edema, and small hydroceles. Patients with secondary infections may also present with fever and a purulent reaction. The hallmark of clinical disease is lymphedema. Patients in the prepatent period (50-150 d) may develop acute lymphedema of the scrotum that remits spontaneously or after medical treatment. In these patients, lymphatic tissues show typical changes of filarial infection, but adult worms are rarely found. In contrast, patients with established infections develop permanent lymphatic scarring, which results in progressive lymphedema. The genitals and lower extremities are the areas most commonly affected. Elephantiasis of the penis and scrotum in patients with filariasis is the most common clinical problem encountered by urologists. Secondary bacterial infections of the skin and local lymph nodes are common in these patients. Although bacteria play no role in chyluria or filarial hydrocele, elephantiasis and lymph scrotum are often superinfected. Bacterial or fungal infections (most commonly streptococci) lead to recurrent lymphangitis, erysipelas, chronic ulcers, or persistent fungal crusting, aggravating the clinical conditions. Chyluria develops before elephantiasis in young adult patients. Chyluria results from obstruction of the retroperitoneal lymphatic channels, which leads to dilatation and rupture in the urinary collecting system. Initially, chyluria may alarm patients; however, subsequently, it may be disregarded. Occasionally, urinary protein loss may be significant and may lead to hypoalbuminemia and anasarca. Most cases of chyluria are intermittent and respond to bed rest and abdominal binders to increase intra-abdominal pressure. Retrograde lymphangiography and lymphosclerosis can be used in an attempt to treat persistent cases. Filarial hydroceles vary significantly in size. They can grow very large and may become socially unacceptable and cause significant morbidity and discomfort. Differentiating filarial hydrocele from idiopathic hydrocele is difficult in many cases. A history of exposure to infection from traveling to or residency in endemic areas is suggestive. The patient should be examined for other manifestations of filariasis. Patients with filarial hydroceles often have a thickened spermatic cord and epididymis with firm nodules. During surgery, the tunica is thickened with calcifications in the wall, and the hydrocele fluid is milky. These findings are uncommon in patients with uncomplicated idiopathic hydroceles. Microfilariae and adult worms are rarely detected in hydrocele fluid. INDICATIONSSection 3 of 11
Contrary to the conclusions in previous literature, a recent double-blind study in Indications for hydrocele surgery include the following:
CONTRAINDICATIONSSection 4 of 11
Because of the scarcity of information regarding surgical treatment of filarial hydrocele, clear contraindications have not been elucidated. Standard contraindications to surgical procedures probably apply. WORKUPSection 5 of 11
Lab Studies
Imaging StudiesUltrasonography: Lymphatic obstruction can be demonstrated on ultrasonography. Motile adult worms may be seen in symptomatic and subclinical filarial hydroceles. The characteristic movements of adult filarial worms are called the filarial dance sign (FDS) and are a reliable diagnostic finding. Ultrasonography may also be used to monitor response to treatment. TREATMENTSection 6 of 11
Medical therapyIn 1997, the World Health Assembly (WHA) passed a resolution calling for the initiation of lymphatic filariasis–elimination programs by the governments of endemic areas. As of 2005, the Global Programme to Eliminate Lymphatic Filariasis (GPELF) has reached nearly 50% of the at-risk world population with mass drug administration of the 2-drug regimens (DEC plus albendazole or ivermectin plus albendazole) or administration of DEC-fortified salt. Epidemiological studies indicate that several countries have demonstrated a near-total absence of transmissions as a result of mass drug administration. Programs aimed at alleviating and preventing disability from lymphatic filariasis are also underway.
Surgical therapyVarious surgical procedures have been developed to remove the edematous tissue in patients with genital elephantiasis. The principles of these operations follow general plastic-surgery principles.
Preoperative DetailsAntibiotics should be initiated the night prior to surgery and continue for a total of 5 days. Analgesics in the form of nonsteroidal anti-inflammatory drugs or oral acetaminophen should be administered as appropriate. Postoperative DetailsStandard postoperative care applies. Most patients may be discharged home the same day. Patients with undue swelling, pain, or oozing from the wound or those in whom a drain has been placed should be observed for 24-48 hours. Follow-upPatients should return for a follow-up visit within 7-10 days. COMPLICATIONSSection 7 of 11
Wound healing is slow and complicated in patients with filariasis because of the lymphedema and chronic scarring. Patients who require excision and grafting of the scrotal or penile skin are at higher risk for graft failure. Wound infections are also common in these patients. OUTCOME AND PROGNOSISSection 8 of 11
Established filarial lymphedema is a progressive condition that tends to follow a stable course within 10-15 years of clinical presentation. No medical treatment has been proven to reverse this pathology; therefore, early diagnosis and treatment are of utmost importance. FUTURE AND CONTROVERSIESSection 9 of 11
Because of the recent advances in medical treatment with single-dose therapies, global elimination of lymphatic filariasis is now considered possible. To interrupt transmission, districts where lymphatic filariasis is endemic must be identified and community-wide programs must be implemented to treat the entire at-risk population. Community education programs are necessary to raise awareness in affected patients. In January 1998, the pharmaceutical company SmithKline Beecham (now GlaxoSmithKline) announced a massive donation program of albendazole (several billion doses) to support this effort. This donation was coupled with a decision by Merck & Co, Inc to expand its ongoing ivermectin (Mectizan) donation program to include treatment of lymphatic filariasis. MULTIMEDIASection 10 of 11
REFERENCESSection 11 of 11
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