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The physiology of gastrocystoplasty: once a stomach, always a stomach
G A Bogaert1, R A Mevorach, J Kim
1Department of Urology, University of California School of Medicine, San Francisco, USA.
Insights
Gastrocystoplasty using stomach body segments continues acid secretion, impacting urinary pH. Medications like histamine-2 receptor antagonists can reduce this acid secretion in children.
Area of Science:
- Urology
- Gastroenterology
- Pediatric Surgery
Background:
- Gastrocystoplasty is a surgical procedure for bladder augmentation or replacement.
- The physiological function of gastric segments used in gastrocystoplasty requires further investigation.
Purpose of the Study:
- To investigate the acid secretion physiology of gastric body segments after gastrocystoplasty.
- To assess the impact of gastric and bladder distention on urinary acid and gastrin levels.
- To evaluate the efficacy of acid-suppressing medications.
Main Methods:
- Prospective study of 13 children post-gastrocystoplasty.
- Measurement of urinary pH, titratable acid, and serum gastrin levels.
- Administration of histamine-2 receptor antagonist or anticholinergic agents.
- Cystoscopy and biopsy in a subset of patients.
Main Results:
- Gastric distention with a meal significantly increased urinary acid secretion and serum gastrin levels.
- Medications partially or markedly inhibited urinary acid secretion in most patients.
- Bladder distention did not stimulate acid or gastrin secretion.
- Histology confirmed normal gastric and bladder tissues.
Conclusions:
- Gastric body segments retain their acid-secreting capacity after gastrocystoplasty.
- Urinary acid secretion can be modulated by pharmacologic interventions.
- Gastrocystoplasty does not impair the native bladder or gastric segment histology.
Abstract:
To determine the physiology of acid secretion after gastrocystoplasty with the body of the stomach we performed a prospective standardized 3-day study in 13 children (median age 12.5 years) who had undergone bladder augmentation/replacement (median postoperative period 2 years). Urinary pH and titratable acid, and serum gastrin levels were measured after gastric distention with a meal and bladder distention with urethral filling at baseline and after medication with a histamine-2 receptor antagonist or an anticholinergic agent. Five children underwent cystoscopy and biopsy of the gastric and native segments of the gastrocystoplasty. In the fasting state pH was neutral, there was no titratable acid in the urine and serum gastrin level was normal in all cases. After a meal urinary acid secretion and serum gastrin level increased markedly. After each medication half of the patients demonstrated marked inhibition of urinary acid secretion after a meal while response was partial in the remainder. In none of the patients was there significant alteration in the pattern of gastrin secretion. Bladder distention did not result in urinary acid secretion or gastrin secretion. The cystoscopic and histological appearance of the native bladder and stomach segment of the gastrocystoplasty in the 5 patients was normal. We conclude that the gastric body segment used in gastrocystoplasty continues to secrete acid as though it were part of the stomach. The secretion of acid in the urine can be decreased with histamine-2 receptor antagonist or anticholinergic medication.