Profile of the brushite stone former.

Area of Science:

• Urology
• Nephrology
• Biochemistry

Background:

• The incidence of brushite (calcium phosphate dihydrate) urinary calculi has notably increased over the past three decades.
• Brushite stones pose unique diagnostic and therapeutic challenges compared to other common stone types.

Purpose of the Study:

• To report the clinical experience and outcomes of managing patients with brushite urinary calculi.
• To identify common characteristics and metabolic abnormalities associated with brushite stone formation.

Main Methods:

• A retrospective review of a prospectively collected database of 82 patients diagnosed with brushite urinary calculi between 1996 and 2008.
• Analysis of patient demographics, stone burden, prior treatments, surgical interventions, stone-free rates, and metabolic urine study results.

Main Results:

• The cohort consisted of 54 males and 28 females with a mean age of 44 years. A high proportion (84.1%) had prior stone events, and 78.3% had undergone shock wave lithotripsy.
• Surgical intervention was required in 80 patients, with percutaneous nephrolithotomy being the most common procedure (76.8%). Stone-free rates were high (92.7%) after treatment.
• Metabolic abnormalities were universal, with hypercalciuria (80.9%), urine pH > 6.2 (61.7%), and low urine volume (57.4%) being most prevalent. Recurrent stone events occurred in 37.8% of patients within approximately 3 years.

Conclusions:

• Brushite stone formers are characterized by substantial stone burden, frequent prior treatments, and a high recurrence rate.
• The presence of brushite stones strongly indicates an underlying metabolic abnormality, particularly hypercalciuria.
• Comprehensive 24-hour urine studies and diligent long-term follow-up are recommended for all patients forming brushite stones.