Monitoring

Once the patient’s stone episode is complete, patients with risk of recurrence should have a full metabolic workup, including serum studies and 24-hour urine, to determine whether any metabolic abnormalities exist that predispose to recurrent stone formation.[47] Patients can then further alter their diet/lifestyle or be placed on the appropriate medication if needed. Patients with cystine stones are more likely to require additional urological interventions over time despite medical therapy and close follow-up.[125]

More info: High-risk stone formers

High-risk stone formers include those with:[47]

General factors

  • Early onset of urolithiasis (especially children and teenagers)

  • Familial stone formation

  • Recurrent stone formers

  • Short time since last stone episode

  • Brushite-containing stones

  • Uric acid and urate-containing stones

  • Infection stones

  • Solitary kidney (the kidney itself does not particularly increase the risk of stone formation, but prevention of stone recurrence is of more importance)

  • Chronic kidney disease (CKD)

Diseases associated with stone formation

  • Hyperparathyroidism

  • Metabolic syndrome

  • Mineral bone disorder

  • Nephrocalcinosis

  • Polycystic kidney disease

  • Gastrointestinal diseases (i.e., jejuno-ileal bypass, intestinal resection, Crohn’s disease, malabsorptive conditions, enteric hyperoxaluria after urinary diversion, exocrine pancreatic insufficiency) and bariatric surgery

  • Increased levels of vitamin D

  • Sarcoidosis

  • Spinal cord injury, neurogenic bladder

Genetically determined stone formation

  • Cystinuria (type A, B, AB)

  • Primary hyperoxaluria

  • Renal tubular acidosis type I

  • 2,8-Dihydroxyadenine

  • Xanthinuria

  • Lesch-Nyhan syndrome

  • Cystic fibrosis

Drug-induced stone formation

Anatomical abnormalities associated with stone formation

  • Medullary sponge kidney (tubular ectasia)

  • Ureteropelvic junction obstruction

  • Calyceal diverticulum, calyceal cyst

  • Ureteral stricture

  • Vesico-uretero-renal reflux

  • Horseshoe kidney

  • Ureterocele.

Environmental and professional factors

  • High ambient temperatures

  • Chronic lead and cadmium exposure

Periodic 24-hour urine monitoring should be performed in people at risk of stone recurrence to assess the efficacy of medication. Serum laboratory tests should be repeated periodically in patients on pharmacological therapy to assess for adverse effects.[71] Imaging with non-contrast computed tomography (CT) scan, renal ultrasound, or kidney-ureter-bladder radiography should be carried out every 6-12 months to monitor for recurrence or increase in the size of existing stones.[47]

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