Combined use of urinary α1-microglobulin and 99mTc DMSA scintigraphy in the diagnosis and follow-up of acute pyelonephritis and cystitis in children

Objectives: In the absence of specific symptomatology in children and neurogenic bladder disease patients, the early diagnosis of acute pyelonephritis is a challenge, The aim of the present study was to determine if dimercaptosuccinic acid (DMSA) lesion-positive (acute pyelonephritis) patients have elevated urinary alpha(1)-microglobulin (alpha(1)-MG) excretion (no false negatives) and if DMSA lesion-negative (cystitis) patients have normal urinary alpha(1)-MG excretion (no false positives), Methods: A selected population of 62 children above 3 months of age with a proven urinary tract infection were administered a DMSA scan, A control scan was performed after the acute phase of the illness, and the diagnosis of pyelonephritis (n = 44) was made retrospectively. The urinary alpha(1)-MG was determined by immunonephelometry. Results: The urinary alpha(1)-MG-creatinine ratio was highly sensitive (98%) and specific (100%) and correlated with the DMSA scintigraphy images, Only 1 of the 44 patients with pyelonephritis and all of the cystitis patients (n = 18) had a normal urinary alpha(1)-MG (<10 mg/g), The drop in absolute DMSA uptake correlated significantly (r = 0,758, p < 0.001) with the urinary alpha(1)MG-creatinine ratio, The urinary alpha(1)-MG-creatinine ratio was significantly higher (p < 0.02) in bilateral than in unilateral pyelonephritis, Conclusion: DMSA lesion-positive (acute pyelonephritis) patients have elevated urinary alpha(1)-MG excretion and DMSA lesion-negative (cystitis) patients have normal urinary alpha(1)-MG excretion.