Brief review about urinary schistomiasis in the Middle East

1. Urinary Schistosomiasis
Literature Review
Mahmoud Alameddine, MBBS
Associate Consultant Urology
International Medical Center

2. Urinary Schistosomiasis
• Schistosomiasis is a chronic infection caused by the parasitic
trematodes of the genus Schistosoma.
• Human infection begins with free-swimming cercariae penetrating the
skin and eventual development of the adult male and female worms.
• The paired adult worms reside in the venous plexuses of the abdominal
viscera.
• S. mansoni and S. japonicum reside in the mesenteric veins,
leading to gastrointestinal and/or hepatic disease.
• S. haematobium dwells principally in the perivesical venous plexus,
resulting in urinary schistosomiasis

4. S. haematobium egg: small spine at
their terminal end
S. Mansoni egg : small spine at
their lateral edge

6. Epidemiology
• Of the 200 million persons affected with schistosomiasis, 80 to 90
million are infected with S. haematobium. Engels et al, 2002
• As many as 10 to 40 million have obstructive uropathy or other
complications secondary to this parasitic disease. Engels et al, 2002

8. Status of Control Program, WHO

10. Progress achieved in the elimination of schistosomiasis from the
Jazan region of Saudi Arabia.
Al Ghahtani AG, Amin MA. Ann Trop Med Parasitol. 2005
• Prevalence and intensity of Schistosoma haematobium infection in
Jizan have been kept very low for several years.
• No infected snails can now be found in the region and new cases of
human infection with S. haematobium are only being detected in
border villages.
• The strategy to eliminate human infection based on:
i. Case finding
ii. Treatment of infected individuals
iii. Chemical and environmental control of freshwater snails
iv. Health education
v. Screening at primary-healthcare centres, by mobile teams and at
diagnostic units

11. Pathogenesis and Pathology
• Schistosomal disease results directly from the granulomatous
host response to schistosome eggs
• Microscopic examination of tissue shows edematous
granulation tissue diffusely infiltrated by eosinophils,
lymphocytes, and plasma cells
• On gross examination, the areas exhibit in large, bulky,
hyperemic, and polypoid masses projecting into the lumen

12. • In the active stage of disease, schistosomiasis is characterized by
presence of viable eggs in urine or biopsy and multiple large
inflammatory polyps.
• Inactive disease occurs after adult worms have died, and is
characterized by the presence of “sandy patches” which is destroyed
or calcified eggs and the tissues that undergo fibrotic reaction.

13. Chronic Schistosomiasis
• Is often complicated with obstructive uropathy
• The obstructive uropathy is usually asymmetric.
• The location of the obstruction varies from:
i. The urethral meatus (1%),
ii. Interstitial ureter (10% to 30%)
iii. Juxtavesical ureter (20% to 60%)
iv. Lower third of the ureter (15% to 50%)
v. Combination of these areas (30% to 60%)
• Left untreated, schistosomal hydronephrosis advances to
progressive renal impairemnt.

14. Bladder cancer
• Is the final pathologic sequelae of schistosomiasis
• High frequency of squamous cell carcinomas (60% to 90%), with 5%
to 15% adenocarcinomas
• More than 40% of schistosomiasis-associated squamous cell
carcinomas of the bladder are well-differentiated that are exophytic
and carry an overall good prognosis

15. Clinical Manifestations

16. • Hematuria and terminal dysuria is the first sign of
established S. haematobium infection, often appearing 10 to 12
weeks after infection
• Katayama fever (in S. Japonicum): fever, lymphadenopathy,
splenomegaly, eosinophilia, urticaria.
• Involvement of these genital structures often present with scrotal
pain or a testicular mass
• Over time, a late, chronic, active stage developes “schistosomal
contracted bladder” consistent with pelvic pain with associated
urinary urgency, frequency, and incontinence.

17. • Patients finally enter a chronic inactive phase, in which viable
eggs are no longer detected in urine or tissues
• This stage are caused by sequelae of the immune reaction to the eggs
rather than the schistosomal infection itself
• Silent obstructive uropathy may develop throughout this phase
as fibrosis replaces polypoid lesions and the bladder and ureters
undergo irreversible damage
• Unfortunately, 40% to 60% present to us at this stage of their
disease

18. Diagnosis
• The presence of eggs in the urinary sediment is diagnostic.
• If eggs are not found in the urine, a bladder biopsy should be
attempted.
• Serology tests of the blood that combine a FAST-ELISA followed by
Western blot analysis are available.
• But they do not distinguish between acute and chronic disease.
Antibody titers can remain positive even after curative treatment.
• Real-time PCR of the urine is in developmental testing, and may
hold some promise in the future

19. • Since early diagnosis of pre-cancerous conditions associated
with urinary schistosomiasis could save countless lives, studies are
being carried out to find non-invasive methods to detect
schistosome-based bladder cancer
• A variety of tumor markers have been studied in urine specimens.
e.g. Aberrant Methylation of RARb2 and APC Genes in Voided
Urine

21. Medical Treatment
• All patients with schistosomiasis should be treated regardless of the
intensity or apparent activity of their infection
• Praziquantel is the drug of choice for all schistosoma species.
• The recommendation is 2 oral doses of 20 mg/kg (or a single
40 mg/kg dose)
• Cure rates are from 73% to 100%
• Praziquantel is extremely well tolerated
• The lack of serious side effects has made it an excellent agent of
choice in mass chemotherapy campaigns

22. Surgical Treatment
• Anatomic ureteral stenosis, with or without calculi, has been
identified in up to 80% of obstructions. (El-Nahas et al, 2003)
• when there is residual ureteral stenosis after successful
chemotherapy it is usually amenable to surgical intervention.
• Depending on the extent and location of the stricture (excision or
dilatation)
• Balloon dilatation has reportedly proved effective but frequently
followed by repeat stenosis.
• The best outcome is ureteral reimplantation (Leadbetter -Politano
operation)

23. • In long or multisegmental lesions, excision of the affected portion
leaves an inadequate residual ureter for reimplantation.
• Boari flap, ileal interposition or long-term nephrostomy drainage
can be done

24. Can schistosomiasis be eliminated?

25. • Schistosomiasis is being successfully controlled in many countries
but remains a major public health problem, with an estimated 200
million people infected, mostly in Africa.
• Constraints to control include, the lack of political commitment and
infrastructure for public health interventions in some countries.
• Anti-schistosomal drugs are expensive and the cost of individual
treatment is a high proportion of the per capita drug budgets.