Diagnostic Ultrasound - Abdomen and Pelvis

Schistosomiasis, Bladder
TERMINOLOGY
Synonyms
• Bilharziasis, parasitic infection
Definitions
• Infection of urinary system by parasite Schistosoma
hematobium
IMAGING
General Features
• Best diagnostic clue
○ Curvilinear bladder wall calcification in patient from
endemic area
• Imaging findings correspond to pathologic course
○ Acute phase: Nodular bladder wall thickening
○ Chronic phase: Contracted, thick-walled bladder with
calcifications
Ultrasonographic Findings
• Noncompliant, thick-walled, small-capacity bladder with
significant postvoid residual
• Echogenic calcification within bladder wall
• Hydronephrosis and hydroureter due to distal ureteric
stricture
Radiographic Findings
• Calcifications of bladder wall (4-56%)
• ± calcification of ureter (34%), seminal vesicle (late)
Fluoroscopic Findings
• Mucosal irregularity, inflammatory pseudopolyps of
bladder
• Ureteritis cystica, distal ureteric stricture
• Vesicoureteric reflux
CT Findings
• NECT
○ Best delineation of extent of bladder calcification, mural
pathology, ureteral involvement
DIFFERENTIAL DIAGNOSIS
Bladder Calculi
• Mobile echogenic focus within bladder lumen
Bladder Carcinoma
• Irregular wall thickening± focal mass with vascularity
• Associated lymphadenopathy ± multiple sites of
involvement
Urachal Carcinoma
• Intramural exophytic mass arising from dome of bladder
extending toward umbilicus
• May have focal calcification
Cystitis
• Diffuse or focal hypoechoic thickening of bladder wall; no
wall calcification
• Clinical, not imaging distinction
Emphysematous Cystitis
• Infection by gas-forming organism
• Echogenic foci within area of bladder, wall thickening with
ring-down shadowing
• Gas in bladder wall or lumen easily detected on CT
PATHOLOGY
General Features
• Etiology
○ Female parasite discharges eggs into urine and feces
○ Ova hatch into miracidia, infecting fresh water snails
(intermediate host)
○ Cercariae pass from snail to water and penetrate human
skin
○ Pass into lymphatics, lungs, and liver and migrate to
pelvic venous plexus
○ Ultimately eggs are deposited and erode into bladder
wall
Microscopic Features
• Encapsulated eggs in bladder wall/vessels cause
inflammatory granulomatous reaction
• Fibrosis traps ova in tunica propria of bladder wall where
ova die and calcify
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Frequency, urgency, dysuria, hematuria
Demographics
• Epidemiology
○ Endemic in Middle East, India, Africa, Central America,
and South America
Natural History & Prognosis
• Squamous cell carcinoma of bladder is late complication
Treatment
• Drugs: Praziquantel, metrifonate
DIAGNOSTIC CHECKLIST
Image Interpretation Pearls
• Degree of hydronephrosis and irregularity of bladder wall
correlates strongly with prevalence and intensity of S.
hematobium infection, microhematuria, and proteinuria
SELECTED REFERENCES
1. Rinaldi G et al: New Research Tools for Urogenital Schistosomiasis. J Infect
Dis. 211(6):861-869, 2015
2. Sabe I et al: New concept of schistosomiasis lesions of urinary bladder versus
development of bladder cancer. J Egypt Soc Parasitol. 38(1):85-102, 2008
3. Gouda I et al: Bilharziasis and bladder cancer: a time trend analysis of 9843
patients. J Egypt Natl Canc Inst. 19(2):158-62, 2007
4. Mungadi IA et al: Urinary bladder cancer and schistosomiasis in North-
Western Nigeria. West Afr J Med. 26(3):226-9, 2007
5. Wong-You-Cheong JJ et al: From the archives of the AFIP: Inflammatory and
nonneoplastic bladder masses: radiologic-pathologic correlation.
Radiographics. 26(6):1847-68, 2006
6. Degremont A et al: Value of ultrasonography in investigating morbidity due
to Schistosoma haematobium infection. Lancet. 1(8430):662-5, 1985
Diagnoses: Urinary Tract
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