Scrotal filariasis
Scrotal filariasis is a manifestation of filariasis and refers to scrotal involvement from parasitic nematodes of the superfamily Filarioidea.
Epidemiology
Known disease of the tropics and subtropics and a cause of morbidity in Asia, Africa and the Western Pacific regions .
Clinical presentation
Patients may be asymptomatic or present with:
- fever
- scrotal swelling
- loss of sex drive
- testicular atrophy
Pathology
Etiology
Filarial nematodes (sometimes shortened to filariae) are transmitted via mosquito bite to humans. The nematodes invade through the skin and into the lymphatics, where they form nests and multiply.
Lymphatic filariasis is transmitted by different types of mosquitoes:
- Culex spp.: widespread in urban and semi-urban areas
- Anopheles spp.: mainly in rural areas
- Aedes spp.: mainly in endemic islands in the Pacific
Lymphatic filariasis is caused by infection with nematodes (roundworms) of the superfamily Filarioidea. There are three types of these thread-like filarial nematodes:
- Wuchereria bancrofti: responsible for 90% of cases
- Brugia malayi: causes most of the remainder of cases
- Brugia timori: causes a minority of cases
Adult nematodes lodge in the lymphatic system and disrupt the immune system.
Radiographic features
Ultrasound
Dilated lymphatic channels (average diameter 6 mm) containing curvilinear echogenic undulating structures representing the microfilariae (usually 5-6) exhibiting the characteristic - but not pathognomonic - "filarial dance sign".
The parasites may affect the scrotum unilaterally or bilaterally and cause an associated hydrocele.
Treatment and prognosis
Treatment options include diethylcarbamazine (DEC) 6 mg/kg body weight in combination with albendazole.
Complications
Grossly dilated lymphatics and edema progressing to elephantiasis.
Differential diagnosis
