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Introduction: A prospective study was conduit on prenatally diagnosed primary non-refluxing megaureters (PM), followed with observational management. The purpose was to evaluate the impact of urinary tract infections (UTIs) on natural history and management of PM, during the first year of life.
Materials and Methods: all patients with prenatally diagnosed PM, born between January 2007 and April 2013, were prospectively followed with observational management. Antibiotic prophylaxis was administered in all cases but those with mild dilatation (retrovesical ureter <10mm and hydronephrosis grade <3). Voiding cystourethrogram was performed to exclude reflux. Observation consisted of monthly urine culture, trimestral clinical evaluation and trimestral renal ultrasonography; MAG3 nuclear scan was performed once, over 1 month of age. Events of interest during the first year of life were: development of UTIs, spontaneous resolution of PM, need of surgery.
Results: 42 patients (38 males, 4 females) with 53 PM were included. PM was bilateral in 11, left in 24, right in 7. At first ultrasound, ureteral retrovesical diameter was<10mm in 22 PM and ≥10mm in 31; hydronephrosis grade was 1 or 2 in 28, 3 in 16 and 4 in 9. MAG3 scan, performed in 33 patients with 40 PM, showed the following drainage curves (according to O’Reilly’s classification): type a (normal) in 5, type b (obstructed) in 1, type c (dilated non-obstructed) in 23, type d (partially obstructed) in 4. Antibiotic prophylaxis was not administered to 13 patients (16 PM) with mild dilatation: 1/16 patient developed 1 afebrile UTI. Antibiotic prophylaxis was administered to the remaining 29 patients (37 PM) with moderate/severe dilatation; UTIs developed in 8/29 (27%) : 1 single episode in 3 patients, recurrent UTIs in 1, febrile UTIs in 2 and urosepsis in 2. Overall, 9/42 (21%) patients developed UTIs during observation: 3/9 required hospitalization. In none of these 9 patients a change in management was required. Among 9 patients with UTIs, 3 showed a type b or d curve at renogram. On the other side, among 5 patients with type b or d curve, 3 developed UTIs (2/3 urosepsis with hospitalization). At 1 year of age, 11 PM had spontaneously resolved, 27 had improved, 13 were stable and 2 had needed ureteral reimplantation (because of obstruction and reduced function at renogram, associated with worsening hydronephrosis). In the subgroup with mild dilatation (13 patients with 16 PM), 7/16 PM resolved, 5/16 improved and 1 was stable.
Conclusions: observational management of prenatally diagnosed PM is safe during the first year of life. Most of cases spontaneously improve, while surgery is rarely needed under one year of age. UTIs can develop during the first year of life, regardless of antibiotic prophylaxis, but they are well tolerated and do not seem to modify outcome. Patients with obstructive or partially obstructive renographic drainage curves, seem to develop more severe UTIs, requiring hospitalization. In cases with initial mild dilatation antibiotic prophylaxis is not required, incidence of UTIs is negligible and hydroureteronephrosis is likely to resolve or improve within the first year of life.