Overview 3% of population have renal stones. Renal stones is the commonest reason for emergency urological admissions. Its peak presentation is during the summer months (dehydration). 90% of urinary calculi are radio-opaque and so are able to be visualised through imaging.
Nephrolithiasis: Refers to the condition of having stones (calculi) in the kidney or collecting system.
Urolithiasis: Refers to the condition of having stones (calculi) anywhere along the urinary tract
Sites of Contriction in the ureter
|Remember These sites are common sites where renal stones can get stuck
|Composition of stone
|Factors favouring stone formation
|Hypercalciuria, hyperoxaluria, hypocitraturia, and dietary risk factors such as a low calcium intake, high oxalate intake, high animal protein intake, high sodium intake.
|Gout and diseases involving rapid cell turnover, such as leukaemias, lead to uric acid à uric acid stonesA low pH favours (chronic diarrhoeal states, gout, diabetes, obesity).
|Usually associated with a genetically determined defect in the renal transport of certain amino acids, including cystine
|Magnesium Ammonium Sulphate (Struvite)
|Persistent alkaline urine due to an UTI (Proteus or Klebsiella).
|Common Risk Factors
|Low fluid intake, previous nephrolithiasis, Family Hx of nephrolithiasis.
|Side note Struvite staghorn calculi classically present with recurrent UTIs.
|Remember Approximately 80% of calcium kidney stones are calcium oxalate
The driving force behind stone formation is the supersaturation of urine.
It is not necessary to treat every kidney stone. As a rule of thumb, the younger the patient, the larger the stone and the more symptoms it is causing, the more inclined we are to recommend treatment.
Treatment options for kidney stones
|Percutaneous nephrolithotomy is the removal of a kidney stone via a ‘track’ developed between the surface of the skin and the collecting system of the kidney.
Acute management for ureteric stones
|Indication for intervention to relieve obstruction and/or remove the stone
|Impaired renal function
|Prolonged unrelieved obstruction
|Remember Almost 70% of stones 5mm or less and almost 50% of stones 6–10mm in diameter will pass spontaneously over a period of 3–6 weeks or there- abouts
Treatment for ureteric stones
Treatment of bladder stones
Prevention of future stones
|Watch Video Urinary (Kidney) Stones - Overview