Management of renal Stones for the non-specialist

Abstract

Risk factors for stone formation are categorized into intrinsic and extrinsic causes. Intrinsic causes include age, family history and sex. The peak age of presentation is 40-60 years old. Patients with a first degree relative with renal stones have an increased risk (RR 2.5). 3 The relative risk between men and women has narrowed over the past decade from 3:1 to 1.3:1 (ibid). Obesity, fluid intake and diet are the most important extrinsic risk factors. There is a strong correlation between BMI and stone formation. A BMI of >27.5 doubles the relative risk compared with a BMI of 20-22.5. 4 Fluid intake is inversely correlated with stone formation. Consuming >2500 mls/day halves the relative risk compared with <1250 mls/day. 5 A low meat intake (<50g/day) halves the risk of stone formation compared with a high meat intake (>100g/day). 4 Perversely a low, rather than high, calcium diet predisposes to calcium stone formation. 5 Differential diagnosisOther renal causes of acute flank pain include: pyelonephritis (typically fevers, rigors and vomiting with infection evident on urine dipstick); blood clot ureteric obstruction (secondary to frank Citation: Menzies-Wilson R, Folkard S, Somani B. Management of renal Stones for the non-specialist. Int J Fam Commun Med. 2018;2(2):38-41.