urinary schistosomiasis

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Schistosoma haematobium is the most important cause of urinary schistosomiasis.

  • develops due to the granulomatous inflammatory response to deposited eggs in tissues
    • adult worms are present in the peri-vesical venous plexus (migrated to this site via the porto-systemic anastomosis at the level of the third lumbar vertebra)
    • females travel to the bladder and lay eggs. Eggs that fail in getting their freedom remain trapped in the bladder wall leading to granuloma formation
  • it is the most important parasitic disease that occurs in the urinary tract (1,2).

The infection typically involves the bladder, lower ureters, seminal vesicles, and, less frequently, the vas deferens, prostate, and the female genital system (2).

Clinical presentation of the infection includes:

  • terminal haematuria
    • appears 10-12 weeks after infection
    • is the first sign of established disease
    • in severe cases, the whole urine sample can be dark coloured.
    • maybe confused with menses in girls
  • dysuria
  • increased frequency of micturition
  • late manifestations
    • proteinuria (often nephrotic syndrome)
    • bladder calcification
    • ureteric obstruction
    • secondary bacterial infection in the urinary tract
    • renal colic
    • hydronephrosis
    • renal failure (1,2,3)

In children, structural abnormalities of the urinary tract may be seen in some instances (1).

Chronic urinary schistosomiasis is considered to be associated with squamous cell carcinoma of the bladder

  • in Egypt, the incidence of bladder cancer has decreased in line with decreasing prevalence of schistosomiasis over the past few decades.
  • bladder squamous cell carcinomas caused by S haematobium  tend to be well differentiated and metastasise locally
  • possible carcinogenic factors are : nitrosamines, β-glucuronidase, and inflammatory gene damage 
  • another theory explain that schistosomiasis lesions intensify the exposure of the bladder epithelium to mutagenetic substrates from tobacco or chemicals (2,3)

In women

  • genital disease is seen in around a third of women infected with S haematobium .
  • eggs migrating to the genital tract causes inflammatory lesions in the ovaries, fallopian tubes, cervix, vagina, and vulva.
  • lower genital tract sandy patches are pathognomonic for female genital schistosomiasis
  • infection results in pain and has been associated with stress incontinence, infertility, and increased risk of abortion
  • advances forms of the genital tract lesionscan increase transmission of HIV (3)

In men

  • can present with haematospermia, orchitis, prostatitis, dyspareunia, and oligospermia.
  • resolve more readily after antischistosomal treatment than do those of female genital schistosomiasis (3)

Note:

  • dysuria and haematuria occur in early and late disease

Reference:

Last reviewed 01/2018

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