Schistosomiasis (Schistosoma haematobium)
Presentation
- Pathophysiology: repeat exposure required for clinical manifestations, otherwise short term exposure leads to adult worms dying within 3-5yrs and no parasitic reaccumulation
- Acute: rash, fever, headache, diarrhea, eosinophilia, urticaria
- Hematuria: considered sign of "male puberty" in some cultures, can cause anemia
- Eggs accumulate and calcify in GU tract, leading to decreased compliance and obstruction
- LUTS: bladder contraction can lead to volumes as low as 50mL with LUTS
- Hydroureter: may be segmental (downstream fibrosis without upstream hydronephrosis), tonic (thick-walled, impaired peristalsis, with complete upstream dilation), or atonic (thin walled, atrophic, upstream dilation)
- UTI: bacterial superinfections common
- Bladder cancer: squamous cell more common, may be synergistic with tobacco
- Female infection: fibrotic nodules in uterus, cervix, and GU tract, can lead to dyspareunia, infertility, and vaginal bleeding
Diagnosis and Management
- Lab diagnosis: eggs in urine/stool is gold standard, PCR is highly sensitive but less available, collect urine between 9AM-3PM (max shedding around noon) rectal biopsy preferred over bladder biopsy, can use ELISA
- Imaging: KUB may show calcified bladder, IVU shows hydronephrosis and obstructed ureters
- Praziquantel: 20mg/kg x2 6-8hr apart on same day, can repeat if concern for recurrent/persistent infection, mild side effects
- Surgery: indicated for bladder hemorrhage, contracted bladders, persistent ureteral obstruction after medical therapy (can use balloon dilation)
Lymphatic filariasis (LF)
Presentation
- Species: Wuchereria bancrofti, Brugia malayi, and Brugia tiimori
- Acute infection: fever, enlarged LN, and lymphangitis, scrotal pain, and scrotal lymphatic drainage
- Hydrocele: can be large, thick fibrous tunica with cholesterol/calcium deposits
- Funiculoepididymitis: rarely causes orchitis or sterility, may be mistaken for testis cancer
- GU elephantiasis: almost always due to LF, usually in areas with poor medical care, skin thickening, can have bacterial superinfection
- Chyluria: due to damaged lymphatics, can lead to malnutrition
Diagnosis and Management
- Diagnosis: based on clinical picture and location/travel history, may be able to see microfilariae on blood smear, can use ELISA/PCR
- Medical treatment: diethylcarbamazine 2mg/kg PO TID x1 day for active infection, alternates include albendazole 400mg PO BID x3 weeks or ivermectin 150-400ug/kg PO x1 dose, can consider adding doxycycline 200mg/d PO x6 weeks to suppress microfilaremia
- Surgical treatment: rarely indicated, can consider hydrocele drainage or resection, consider lymphatic ligation, scrotal reconstruction
Other parasites
Arthropod
- Scabies: caused by parasitic mite (Sarcoptes scabiei), presents with itching and nodules in serpiginous lines (can take up to 3mo to present), diagnosed with mites on skin scraping, manage with permethrin 5% cream or ivermectin 200ug/kg PO q2w x2 doses, wash clothes/bedding in hot water or seal in a bag x3 days
- Crabs: caused by pubic lice (Pediculosis pubis), presents with itching and rash, diagnosed with lice/nits on hair shaft, manage with permethrin 1% cream rinse (q1w x2 doses) or malathion 0.5% lotion, wash clothes/bedding in hot water or seal in a bag x3 days
Non-Arthropods
- Onchocerciasis (Onchocerciasis volvulus): can cause scrotal elephantiasis, treat with ivermectin 150ug/kg PO x1, repeat q6-12mo until asymptomatic, can consider adding doxycycline 200mg/d PO x6 weeks to suppress microfilaremia
- Loaiasis (Loa loa): can cause hematuria/proteinuria (30%), rarely causes hydrocele and lymphadenitis, treat with diethylcarbamazine 2-3mg/kg PO TID 2-3 weeks, treatment in patients with high levels microfilaremia can cause encephalopathy
- Echinococcosis (Echinococcus granulosus): can cause painful renal cysts (2-3%), may have large cyst with calcified wall, manage with albendazole 400mg PO BID 1-6mo or surgical excision (cyst rupture can cause anaphylaxis)
- Enterobiasis (Enterobius vermicularis): commonly cause perianal pruritus, can spread through female GU tract and cause granulomas/adhesions, treat with albendazole 400mg PO or mebendazole 100mg PO x1
- Amebiasis (Entamoeba histolytica): can cause renal infection or perianal/genital ulcers, treat with tinidazole 2g PO QD x3-5d or metronidazole 750mg PO TID x10d, followed by paromomycin 8-12mg/kg PO TID x7 days or iodoqinol 650mg PO TID x20d
References
- AUA Core Curriculum
- Chang, A., B. Blackburn, and M. Hsieh. "Tuberculosis and Parasitic Infections of the Genitourinary Tract." Campbell-Walsh-Wein Urology. 12th ed. Elsevier (2020): 1129-1201.
- Wieder JA: Pocket Guide to Urology. Sixth Edition. J.Wieder Medical: Oakland, CA, 2021.