Cortical scintigraphy in the evaluation of urinary tract infections

Should renal ultrasonography be done routinely in children with first urinary tract infection?

To reassess the impact of renal ultrasonography on the care of children with first febrile urinary tract infection (UTI) we conducted a computer search and review of medical records of (1) all children who were admitted to our hospital with first febrile urinary tract infection and underwent renal ultrasonography during a 25-month period beginning February 1, 1995, (2) all children diagnosed by ultrasound to have hydronephrosis during the same time period. Of a total of 124 patients with UTI, renal ultrasound appeared normal or showed evidence of acute pyelonephritis in 105 (84.7%), and in another nine (7.2%) it showed only minor findings. In 10 children (8.1%) ultrasound showed hydronephrosis and/or hydroureter. In eight of the latter 10, voiding cystourethrography showed vesicoureteral reflux; in one, posterior urethral valves; and in one, who had a unilateral nonobstructed dilatated system, cystography appeared normal. Except for the last patient, who was given prophylactic antibiotics and continued to have urinary tract infections, in no other case did ultrasound alone have any impact on the patient's management. Four children with both abnormal-appearing renal ultrasound and voiding cystourethrography required surgical intervention. One hundred of the 124 children had a voiding cystourethrogram. In 38 children it detected vesicoureteral reflux and, in another two, bladder abnormalities. Thirty-five of those with abnormal-appearing cystogram but without an indication for surgery were given prophylactic antibiotics. During the same 25-month period, 63 children without urinary tract infection were diagnosed by ultrasound with hydronephrosis. In 45 of them (71.4%) the urologic abnormality had already been detected by prenatal ultrasound. Fourteen of these 45 children (31.1%) required surgery, all for congenital anomalies related to obstructive uropathy. We conclude that routine renal ultrasonography in children with first urinary tract infection has negligible influence on their clinical management. This seems to be due to the recent widespread use, in industrialized countries, of maternal-fetal ultrasonography, which already detects a significant number of children with congenital obstructive uropathy prenatally. On the other hand imaging of the lower urinary tract is of high yield and contributes significantly to patient care. Therefore, whereas imaging of the lower urinary tract should continue to be done routinely in children with first urinary tract infection, renal ultrasound may be reserved for more select cases.

Uroradiologic evaluation of children with urinary tract infection: are both ultrasonograpy and renal cortical scintigraphy necessary?

OBJECTIVE

To compare the findings of renal ultrasonography (RUS), 99mTc glucoheptonate renal scan (GHS), and voiding cystourethrography (VCUG) in children with urinary tract infection.

DESIGN

Prospective, masked, clinical study.

SETTING

Single center, multidisciplinary, inpatients.

PATIENTS

Consecutive cases (N = 50) of children aged 2 months to 15 years (8 boys, 42 girls) with pyelonephritis in whom uroradiologic investigation was indicated.

MEASUREMENTS AND MAIN RESULTS

All patients underwent GHS, 48 had RUS, and 2 had intravenous pyelography. All but one of the patients had a VCUG. Fifteen children were found to have vesicoureteral reflux (6 unilaterally, 9 bilaterally). Of 96 kidneys evaluated by both GHS and RUS, 53 were abnormal by GHS versus 28 by RUS (p < 0.001). Findings of both GHS and US were normal in 36 kidneys and abnormal in 21 kidneys. In 32 kidneys only GHS showed abnormalities. In 7 kidneys only RUS showed abnormalities; 5 of them had mild to moderate pelvic dilation caused by reflux, which was confirmed in all 5 by VCUG. The VCUG demonstrated reflux in another four units with normal GHS and RUS findings. All combined, GHS and VCUG detected 62 of 64 abnormal renal units (96.9%). In the other two cases, RUS showed only focal hyperechogenicity of questionable importance.

CONCLUSION

In the event that one elects to use GHS for the uroradiologic evaluation of children with urinary tract infection, it can be supplemented by VCUG alone, and RUS can be saved for special cases.