Uric Acid Nephrolithiasis: A Systemic Metabolic Disorder

Abstract

Uric acid nephrolithiasis is characteristically a manifestation of a systemic metabolic disorder. It has a prevalence of about 10% among all stone formers, the third most common type of kidney stone in the industrialized world. Uric acid stones form primarily due to an unduly acid urine; less deciding factors are hyperuricosuria and a low urine volume. The vast majority of uric acid stone formers have the metabolic syndrome, and not infrequently, clinical gout is present as well. A universal finding is a low baseline urine pH plus insufficient production of urinary ammonium buffer. Persons with gastrointestinal disorders, in particular chronic diarrhea or ostomies, and patients with malignancies with a large tumor mass and high cell turnover comprise a less common but nevertheless important subset. Pure uric acid stones are radiolucent but well visualized on renal ultrasound. A 24 h urine collection for stone risk analysis provides essential insight into the pathophysiology of stone formation and may guide therapy. Management includes a liberal fluid intake and dietary modification. Potassium citrate to alkalinize the urine to a goal pH between 6 and 6.5 is essential, as undissociated uric acid deprotonates into its much more soluble urate form.

The bladder ran dry: bilateral ureteral obstruction

“…In addition, in this setting, the use of non-steroidal anti-inflammatory drugs (NSAIDs) significantly increases the risk of NSAID nephrotoxicity 3. Thus, we did not suspect a predominant role of obstructive uropathy here until complete anuria in a patient with a history of gout and ‘unilateral’ nephrolithiasis led to the CT-based diagnosis of acute bilateral ureteral obstruction, possibly precipitated by the volume depletion and oliguria 4. The absence of renal colic and the false-negative plain films (since uric acid stones are radiolucent) and ultrasound contributed to the diagnostic delay which ended when anuria supervened.…”

High water intake in preventing the risk of Uric Acid Nephrolithiasis: A systematic review and meta-analysis

“…The prevalence of UAN is increasing recent years, and now accounts for approximately 7% to 10% of kidney stone formers [1,3]. Multiple factors contribute to the formation of uric acid kidney stones.…”

“…UAN constitutes around 10% of kidney stones. The incidence of UAN has constantly increased over recent years [1][2][3]. The reported to be 15-16% in Japanese and Chinese descendants in San Francisco, 28% in Pakistan, 22% in Israel%.…”

The efficacy of medical dissolution therapy for uric acid nephrolithiasis

“…Uric acid nephrolithiasis is a systemic disorder necessitates complete metabolic evaluation prior to medical management [4]. In this study, only 12 (50%) of the patients had a documented serum uric acid level prior to initiation of medical dissolution therapy.…”