Disease - Renal stones

From CambridgeNotes

  • 10% lifetime incidence; typically affects 35-44 year olds
  • Aetiology: dehydrated, urinary tract infections (UTI), hypercalcaemia, hypercalciuria, raised oxolate
  • Pathology: calcium oxolate > struvite (especially with Proteus) > others

History and Examination

  • Pain loin to groin; nausea and vomiting; urinary symptoms; fever
  • Patient often writhing (compare with peritonism); tender loin

Differential Diagnosis

  • Renal colic: stones, transitional cell carcinoma, lymph nodes
  • Other pain: abdominal aortic aneurysm, appendicitis, pyelonephritis, diverticulitis, gynaecological causes

Investigations

  • Urine dipstix (haematuria in >90%); MSU microscopy, culture and sensitivity
  • FBC, U&E and creatinine; calcium, urate, phosphate, bicarbonate, PTH may be useful
  • Consider ultrasound?
  • KUB X-ray then IVU
    • Stop metformin 24 hour prior, steroid cover for asthma
    • 80% stones visible, often at pelvic-ureteric junction, sacro-iliac junction, vesico-ureteric junction
    • Compare with phlebolith that are round, smooth and multiple
    • Obstructions have column of contrast, compare with peristalsis
    • CTU is an alternative with >97% stones visible

Treatment

  • Admit if: fever, single kidney, inadequate pain relief, poor social support, or difficult to arrange outpatient follow-up
  • Encourage fluids; pain with NSAIDs or opiates; antibiotics if evidence of infection
  • Surgery: if evidence of sepsis or obstruction perform as emergency; otherwise if persistent (>3 weeks) e.g. >1 cm stone
    • ESWL: extracorpreal shock wave lithotripsy
    • Ureteroscopy
    • Open or laparoscopic surgery
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