A correlation study between macro- and micro-analysis of pediatric urinary calculi

The aim was investigate the relationship between macro- and micro-compositions of pediatric urinary stones by using two combined analytical techniques: Fourier transform infrared spectroscopy (FT-IR) and inductively coupled plasma-optical emission spectrometry (ICP-OES).

A total of 74 consecutive urinary calculi were collected from children. Each stone was divided into two equal portions. One part was analyzed by FT-IR to determine mineralogical composition. The second part underwent analysis by ICP-OES to determine the heavy metals and trace elements contents. The association between mineralogical components and elemental contents was evaluated.

The percentages of mineralogical components of the stones were 78.3% calcium oxalate monohydrate, 63.5% calcium oxalate dihydrate, 24.3% ammonium urate, 13.5% uric acid, 10.9% dahllite, 12.1% brushite, 8.1% ammonium calcium phosphate, 8.1% struvite, 4.5% cysteine, and 2.7% were xanthine. There were seven elements with significant different high concentrations; magnesium, sulfur, strontium, lead, chromium, calcium, and phosphorous. High calcium-containing stones had significant higher contents of magnesium, lead, strontium, and zinc (p<0.05) than low calcium-containing stones. Phosphate stones had significant contents of magnesium, strontium, zinc and chromium when compared to other stones (p<0.05).

Pediatric urinary stones have variable biochemical structures. The stones contained many significant heavy metals and trace elements in different concentrations, and phosphate stones enclosed most of the heavy and trace elements.