Renal Stone Disease


  • Common (prevalence ~1.2%; lifetime risk around 7%)
  • There is a strong risk of recurrence (50% at 5-7 years)


  • Size
    • <5; 5-10; 10-20; >20 mm
      • Most under 5mm will pass spontaneously
  • Location
    • Upper, middle or lower calyx (within the kidney)
    • Renal Pelvis
    • Upper, middle, distal third of ureter
    • Bladder/Urethra
  • X-ray characteristics
    • Radiopaque e.g. Calcium oxalate; calcium phosphate (both most common)
    • Poor radiopacity e.g. magnesium ammonium phosphate (struvite); apatite; cystine
    • Radioluscent e.g. urate; ammonium urate; xanthine; drug stones
  • Aetiology
    • Non-infectious stones – most commonly a metabolic defect (predisposing factors include low urine volume/fluid intake; high protein and salt diet; high sodium/oxalate/urate excretions or low citrate excretion; hypercalcaemiaileal disease/resection; renal tubular acidosis)
      • Calcium oxalate and phosphate stones; urate stones
    • Infections
      • struvite
    • Genetic causes (e.g. familial hypercalciuria; medullary sponge kidney; cystinuria; renal tubular acidosis type I; primary hyperoxaluria)
    • Other predisposing factors include hyperparathyroidism


Clinical Features

  • Majority are asymptomatic (incidental stone disease).  Around one third will develop symptoms
  • Classic acute loin to groin colicky pain associated with nausea and vomiting
    • + renal angle tenderness and microscopic haematuria (gross haematuria may also be seen)
    • Fever/chills are not classical of stone disease but may be seen if there is associated infection
    • there may also be symptoms of urinary tract infection i.e. frequency, dysuria
  • Pain is often restless, patients often seen writhing in distress


  • While most stones (calcium containing) can often be visualised on AXR, gold standard is CTKUB (NCCT); however, in Tayside, the investigation of choice is CT-stone search
    • IVU is not routinely used for investigating flank pain
  • Other investigations include
    • urinalysis + culture (consider infection)
    • Serum U&Es (calcium, phosphate; bicarbonate; urate; eGFR/creatinine)
      • PTH levels (if raised calcium)
    • Also FBC and CRP (infection)
  • If a stone has been passed, stone analysis
  • With recurrent stones, urine studies (urea, electrolytes etc) should be performed also


  • Pain management
    • NSAID 1st line (diclofenac) and opiates 2nd line (oromorph or IM morphine)
  • Stone relief
    • If stone <10mm and there are no indications for active removal, observation and periodic evaluation is possible (European guidelines also suggest medical expulsion therapy- α-blocker e.g. tamsulosin; particularly for stones 5-10mm)
      • Indications for active removal include
        • stones unlikely to pass spontaneously (>15mm); obstruction caused by stones; renal dysfunction; persistent pain despite analgesia; comorbidity (especially patients with a solitary kidney)
    • The choice of procedure for active removal depends on stone size and location
      • Kidney
        • >20mm- Percutaneous nephrolithotomy (1st line unless contraindicated); Retrograde intrarenal surgery (or Flexible uretorenoscopy) or Electrocorporeal Shock Wave Lithotripsy (ESWL) (second line; choice depends on whether stone is susceptible to ESWL)
          • Contraindications to PNL include
            • untreated UTI; tumour in the area or potential malignant kidney tumour; pregnancy
          • Factors making ESWL less likely include
            • Shockwave-resistant stones e.g. calcium oxalate monohydrate, brushite or cystine; Steep infundibular pelvic angle; long lower pole calyx; narrow infundibulum (<5mm)
        • 10-20mm- ESWL or Endourology (PNL/URS) (depends again on influencing factors)
        • <10mm- ESWL 1st line (or URS if unsuitable); PNL 2nd line
    • NB If there are complications
      • If there’s hydronephrosis, urgent decompression with percutaneous nephrostomy
  • Prevention of recurrence/metabolic management
    • Fluids/General
      • Aim for urine output >2.5l in 24 hours
      • Restrict salt intake
      • Avoid excessive animal protein
    • For calcium stones
      • Normocalciuria
        • Oral potassium citrate (increases urine pH and citrate excretion)
      • Hypercalciuria
        • Thiazide diuretics (often with potassium citrate)
          • If magnesium loss is a concern (chronic diuretic use), consider potassium magnesium citrate
      • Hyperuricaemia/Hyperuricosuria
        • Allopurinol and potassium citrate
      • Hyperoxaluria
        • If >1mmol/day- pyridoxine (start low-dose)
        • If >0.5mmol/day- calcium supplementation (250-1000mg QDS- beware rise in calcium)
    • For struvite stone- treat infection; prevention may include acetohydroxamic acid (AHA) although side effects are troublesome
    • Cystine stones- potassium citrate and other cystine binders e.g. D-penicillamine/ tiopronin

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