Related Experiment Video
Updated: Aug 11, 2026
07:45
Estimation of Urinary Nanocrystals in Humans using Calcium Fluorophore Labeling and Nanoparticle Tracking Analysis
Published on: February 9, 2021
Metabolic studies in kidney stone disease
S Y Wong1, S R Slater, R A Evans
1Biochemistry Department, Concord Hospital, Sydney, Australia.
The Quarterly Journal of Medicine
|March 1, 1992
Summary
Patients with kidney stones exhibit altered calcium and phosphate metabolism. Their parathyroid glands may have a different set point, leading to higher plasma calcium and lower phosphate levels, contributing to stone formation.
Area of Science:
- Nephrology
- Endocrinology
- Calcium Metabolism
Background:
- Kidney stones affect a significant portion of the population.
- Understanding the metabolic factors contributing to kidney stone formation is crucial for developing effective treatments.
- Previous hypotheses suggested calcitriol overstimulation as a cause for hypercalcemia in stone formers.
Purpose of the Study:
- To investigate the differences in calcium, phosphate, and related hormone levels between kidney stone patients and healthy controls.
- To identify metabolic predictors of kidney stone formation.
- To evaluate the role of calcitriol and parathyroid hormone (PTH) in the pathophysiology of kidney stones.
Main Methods:
- Collected 24-hour urine samples from 59 kidney stone patients and 31 healthy controls.
- Administered a 6-hour 'fast and load' test with oral calcium intake.
- Measured fasting and post-load plasma and urinary levels of calcium, phosphate, urate, oxalate, citrate, calcitriol, and PTH.
- Utilized multiple linear regression to identify variables associated with stone formation.
Main Results:
- Kidney stone patients showed higher fasting plasma calcium, serum calcitriol, and fasting urinary calcium, with lower plasma phosphate compared to controls.
- 24-hour urinary calcium excretion was higher in patients, but urate, oxalate, and citrate levels were similar.
- Plasma and urinary calcium increased similarly in both groups after calcium load, with comparable PTH responses.
- Plasma calcium, plasma phosphate, fasting urinary urea, and 24-hour urinary calcium excretion were significant predictors of stone formation.
Conclusions:
- The findings do not support primary calcitriol overstimulation as the cause of elevated calcium in stone formers.
- An abnormality in the parathyroid cell 'set point' is suggested, leading to higher plasma calcium and lower plasma phosphate levels.
- These altered set points in parathyroid hormone secretion appear to be a key factor in kidney stone development.
More Related Videos
Related Concept Videos
01:28Urinary Tract Calculi I: Introduction
Renal calculi, or kidney stones, are solid deposits of minerals and salts formed inside the kidneys. In medical terminology, "calculus" refers to the stone itself, while "lithiasis" describes the process of stone formation. Depending on their location within the urinary system, these stones may be classified as either urolithiasis, when situated within the urinary tract, or nephrolithiasis, when located within the kidneys. Each term signifies the specific impact of the stone.Predisposition...
01:26Urinary Tract Calculi II: Pathophysiology and Clinical Manifestations
Renal calculi, commonly termed kidney stones, are crystalline solid masses that form in the kidneys but can occur at any point within the urinary system, encompassing the kidneys, ureters, bladder, and urethra.The pathophysiology of renal stones involves several key factors: supersaturation of the urine with stone-forming constituents, changes in urine pH, a decrease in urine volume, and the presence of substances that promote or inhibit stone formation.Supersaturation of Urine: This is the...
01:30Urinary Tract Calculi III: Medical Management
The diagnosis of renal calculi involves several imaging techniques, including non-contrast CT scans and ultrasound. These methods help visualize kidney stones, assess their size and location, and detect possible obstructions. Additionally, Measuring urine pH is useful for diagnosing specific stone types, such as struvite (alkaline pH) and uric acid stones (acidic pH). Cystine stones are primarily linked to cystinuria, a genetic condition. A urinalysis helps detect blood in the urine (hematuria)...
01:25Urinary Tract Calculi VI: Surgical Management
Procedures for Kidney StonesMedical intervention is necessary when kidney stones or renal calculi are too large to pass spontaneously (typically greater than 5 millimeters) when stones are accompanied by symptomatic infection (such as fever or pyelonephritis), when they impair kidney function, or when they cause persistent symptoms like severe pain, nausea, or urinary retention. Additionally, patients with only one kidney or those who cannot be treated with medical management also require...
01:28Imaging Studies I: Kidney, Ureter, and Bladder Studies
Kidney, Ureter, and Bladder (KUB) StudiesKidney, Ureter, and Bladder (KUB) studies are standard diagnostic imaging procedures used to assess the anatomy of the urinary system. They are commonly utilized for patients experiencing abdominal pain or urinary symptoms. By using a simple X-ray of the abdomen, KUB studies can reveal structural and pathological abnormalities within the kidneys, ureters, and bladder. These studies are particularly valuable in diagnosing kidney stones, urinary...
01:24Imaging Studies II: Ultrasonography
IntroductionUltrasonography, or renal ultrasound, is a noninvasive medical imaging technique that uses high-frequency sound waves to visualize the kidneys, ureters, bladder, and surrounding tissues.Indications for Urinary System UltrasonographyUrinary system ultrasonography is indicated in various clinical scenarios, such as:Kidney Stones (Urolithiasis): To detect and monitor the size and presence of kidney or urinary tract stones.Hydronephrosis: To assess the dilation of the renal pelvis and...