Comparison of biochemical parameters of blood and urine in spinal cord injury patients and association with urinary stone formation.

Objective: The aim of this study was to compare the biochemical parameters of the urine and blood in spinal cord injury (SCI) patients and healthy subjects.

Methods: Thirty male patients with SCI were enrolled. Biochemical features of the urine and blood of the SCI patients were compared to healthy subjects. Extracted stones were analyzed by X-ray diffraction.

Results: A total of 30 patients with SCI (mean age of 28.77 ± 7.3 years) and 10 healthy subjects (mean age of 27.6 + 6.2 years) were included. Among the patients with SCI; 12 of them (40%) had urinary stones and 18 of them (60%) did not. Urinary stone was localized in the kidneys and bladder in 25% and 75% of the subjects, respectively. The mean duration of cord injury at diagnosis of urinary stone was 9.2 ± 6 months. Urine cultures obtained on admission were negative for the control group, while the microorganism isolation rate was 73.3% in the SCI group. The urinary excretion of citrate and Mg were lower in the patient group compared with control group (p= 0.008, p= 0.001, respectively). As for the diffraction analysis of eight stones; five (62.5%) of the stones were calcium oxalate, two (25%) of them were calcium phosphate, and one (12.5%) was magnesium ammonium phosphate.

Conclusion: Both infection and metabolic changes play an important role in stones formation in SCI patients. The urinary excretion of citrate and Mg was decreased and urinary PH was increased in SCI patients.