# Prospective Study of Urinary Stone Formation in Pediatric Patients with Acquired Brain Injury: A Focus on Incidence and Analysis of Risk Factors

## TL;DR

This study examines the incidence of urinary stones in children with brain injuries and identifies risk factors like physical activity and urine pH.

## Contribution

The study provides the first prospective analysis of urinary stone formation in pediatric patients with acquired brain injury.

## Key findings

- Urinary stones were found in 12.5% of patients and gravel in 14.6%.
- Risk factors included higher urine pH, blood potassium levels, and physical activity before injury.
- Enteral nutrition composition did not influence stone formation despite high vitamin C and protein levels.

## Abstract

Background/Objectives: Little is known about the factors linked with nutrition, infections, and physical activity, which may influence urinary stone formation in patients with acquired brain injury. Previous studies have demonstrated that enteral nutrition mixtures rich in sodium and poor in calcium may promote stone formation in pediatric patients, but a confirmation study is lacking. Moreover, the occurrence of urinary stones and heterotopic ossifications has not been studied regarding incidence. We thus conducted a prospective observational study in an unselected pediatric population with acquired brain injury, to estimate the incidence of urinary stones and heterotopic ossifications and analyze the associated factors. Methods: Prospective observational study: We recruited all patients with enteral nutrition consecutively admitted to our brain injury rehabilitation unit during a 5-year time-frame. We collected clinical data regarding nutrition, infections, blood and urine exams performed, neurological examinations, and physical examinations. Results: The prospective design allowed us to observe that no patient developed heterotopic ossifications, while urinary stones were found in 12.5% of patients and gravel in 14.6%. Factors associated with stone formation were having a worse subacute GCS, having done intense physical activity before injury, receiving bladder catheterizations, having a higher urine pH, and having higher blood potassium levels. The composition of the enteral nutrition did not influence stone formation, although the nutrition mixtures contained levels of vitamin C and proteins considerably higher than the recommended reference ranges. Conclusions: We have provided an observation of the incidence of urolithiasis in pediatric patients in rehabilitation, which was lacking from the literature. Enteral nutrition, at the amounts received by the patients studied herein, does not seem to have a role in stone formation. We identified a set of risk factors that can be useful for clinicians to pinpoint patients at an increased risk of developing stones.