Brief communication Sonographic screening forurinary tract abnormalities inpatients withSchistosoma haematobium infection: pitfalls inexamining pregnant women

InareaswhereSchistosoma haematobium isendemic, urinary schistosomiasis andpregnancy are frequently concomitant; however, boththeseconditions mayproduce similar urinary tract changes in ultrasound scansandhencetheir differential diagnosis may be difficult. Inpatients withurinary schistosomiasis, focal and/or diffuse urinary bladder wall changes arefrequently detected ultrasonically. Dilatation ofoneorbothureters andprogressive hydronephrosis maybeobserved inmoresevere cases. Satisfactory ultrasound examination oftheurinary bladders ofpregnant womenisgenerally notfeasible because mechanical compression bythefetus ortransitory lower urinary tract infection hampers adequate filling ofthebladder. Pregnancy itself isfrequently associated with dilatation ofoneorbothureters and/or hydronephrosis; this isduetohormonal factors, infection, orcompression ofoneorbothureters bythe enlarged uterus andgrowing fetus. Hence, whensonography oftheurinary bladder isnotfeasible such pregnancy-associated changes arevirtually indistinguishable fromthose caused byS.haematobium, and maybeincorrectly attributed tothelatter. Pregnant women,therefore, should beexcluded fromultrasonic surveys ofurinary schistosomiasis. Incontrast, ultrasound scansofadolescents andofwomenwith positive parasitological findings and/or pathological alterations intheurinary tract should include examination ofthe uterus inorder toassess whether thewomanispregnant; thereby, misinterpretation ofsonographic findings canbeavoided. Pregnant womenwithsignificant hydronephrosis mustbeclosely followed upbyan obstetrician sincethis condition mayindicate a complication ofthepregnancy; insomecasesonlya postpartum examination will permit definitive diagnosis.