Outcomes and rates of dissolution therapy for uric acid stones

The role of the general practictioner in the management of urinary calculi

BACKGROUND

The prevalence of kidney stones tends to increase worldwide due to dietary and climate changes. Disease management involves a high consumption of healthcare system resources which can be reduced with primary prevention measures and prophylaxis of recurrences. In this field, collaboration between general practitioners (GPs) and hospitals is crucial.

METHODS

a panel composed of general practitioners and academic and hospital clinicians expert in the treatment of urinary stones met with the aim of identifying the activities that require the participation of the GP in the management process of the kidney stone patient.

RESULTS

Collaboration between GP and hospital was found crucial in the treatment of renal colic and its infectious complications, expulsive treatment of ureteral stones, chemolysis of uric acid stones, long-term follow-up after active treatment of urinary stones, prevention of recurrence and primary prevention in the general population.

CONCLUSIONS

The role of the GP is crucial in the management and prevention of urinary stones. Community hospitals which are normally led by GPs in liaison with consultants and other health professional can have a role in assisting multidisciplinary working as extended primary care.

Development and external validation of a machine learning-based model to classify uric acid stones in patients with kidney stones of Hounsfield units < 800

The correct diagnosis of uric acid (UA) stones has important clinical implications since patients with a high risk of perioperative morbidity may be spared surgical intervention and be offered alkalization therapy. We developed and validated a machine learning (ML)-based model to identify stones on computed tomography (CT) images and simultaneously classify UA stones from non-UA stones. An international, multicenter study was performed on 202 patients who received percutaneous nephrolithotomy for kidney stones with HU < 800. Data from 156 (77.2%) patients were used for model development, while data from 46 (22.8%) patients from a multinational institution were used for external validation. A total of 21,074 kidney and stone contour-annotated CT images were trained with the ResNet-18 Mask R-convolutional neural network algorithm. Finally, this model was concatenated with demographic and clinical data as a fully connected layer for stone classification. Our model was 100% sensitive in detecting kidney stones in each patient, and the delineation of kidney and stone contours was precise within clinically acceptable ranges. The development model provided an accuracy of 99.9%, with 100.0% sensitivity and 98.9% specificity, in distinguishing UA from non-UA stones. On external validation, the model performed with an accuracy of 97.1%, with 89.4% sensitivity and 98.6% specificity. SHAP plots revealed stone density, diabetes mellitus, and urinary pH as the most important features for classification. Our ML-based model accurately identified and delineated kidney stones and classified UA stones from non-UA stones with the highest predictive accuracy reported to date. Our model can be reliably used to select candidates for an earlier-directed alkalization therapy.

Effect of theobromine on dissolution of uric acid kidney stones

Purpose

Uric acid renal lithiasis has a high prevalence and a high rate of recurrence. Removal of uric acid stones can be achieved by several surgical techniques (extracorporeal shock wave lithotripsy, endoscopy, laparoscopy, open surgery). These stones can also be eliminated by dissolution within the kidneys, because the solubility of uric acid is much greater when the pH is above 6. At present, N-acetylcysteine with a urinary basifying agent is the only treatment proposed to increase the dissolution of uric acid stones. In this paper, we compare the effect of theobromine and N-acetylcysteine on the in vitro dissolution of uric acid calculi in artificial urine at pH 6.5.

Methods

The dissolution of uric acid renal calculi was performed in a temperature-controlled (37 °C) chamber. A peristaltic pump was used to pass 750 mL of synthetic urine (pH 6.5) through a capsule every 24 h. Stone dissolution was evaluated by measuring the change in weight before and after each experiment.

Results

N-acetylcysteine increased the dissolution of uric acid calculi, but the effect was not statistically significant. Theobromine significantly increased the dissolution of uric acid calculi. Both substances together had the same effect as theobromine alone. The addition of theobromine to a basifying therapy that uses citrate and/or bicarbonate is a potential new strategy for the oral chemolysis of uric acid stones.

Conclusion

Theobromine may prevent the formation of new stones and increase the dissolution of existing stones.