Renal tract stones Lachlan Brennan Important surgical topic. Not a lot of surgery involved. Renal tract stones Lachlan Brennan

Since the Stone Age Pain “I will not cut persons laboring under the stone, but will leave this to be done by men who are practitioners of this work” Hippocrates 400BC Agony Misery

“Kidney stones” Litho = stone Urolithiasis = stone in the urinary tract Nephrolithiasis = stone in renal calyces/pelvis Ureterolithiasis = stone in ureter Cystolithiasis = stone in bladder Calculi = stone

Formation Anatomical anchor: Renal calyces, PUJ, VUJ Solute Solvent Inhibitors Crystals Several hypothesis about exact mechanism of stone formation. Citrate inhibits stone formation Anatomical anchor: Renal calyces, PUJ, VUJ

Chemical composition Stone type Frequency Stone forming conditions Calcium oxalate/calcium phosphate 80% High calcium/oxalate/phosphate concentration in urine Uric acid 5% Hyperuricaemia and/or hyperuricosuria **radiolucent stone Cystine 1% Genetic disorder, cystine leaks through glomeruli Struvite 10-15% Infection with urea splitting bacteria Proteus mirabilis, Proteus vulgaris Other Rare Specific metabolic disorders, medications, One way of defining stones is by their chemical composition

History Epidemiology Lifetime prevalence 10-15% Uncommon before age 20, peak 40s-60s, bimodal in women Male > female 3 : 1 Sudden onset, unilateral flank pain Radiation specific to site of stone – abdomen/back, groin/gonads, urethra Haematuria, nausea & vomiting Women – peak 35 and 55 Pain – spasms Nausea due to shared sphlanchin innervation of intestines and renal capsule Gross haematuria in 30% Risk factors

Risk factors Genetic/Anatomical Disease processes Environment Family history (2.5x) Cystinuria Horseshoe kidney Calyceal diverticulum or cyst Ureteral stricture Vesicoureteric reflux Ureterocoele Primary hyperparathyroidism Gout Crohn’s disease Hyperthyroidism Multiple myeloma Sarcoidosis Obesity Hypertension Medications: loop diuretics, thiazide diuretics Pregnancy Low fluid intake Hot weather High sodium diet High oxalate diet Non-exhaustive list Not a surprise they are all men – lifetime recurrence of at least 50%. 15% at 1 year. Oxalate: rhubarb, spinich, tea leaves, nuts Personal history Napoleon, Isaac Newton, Benjamin Franklin, Lyndon Johnson

Examination Signs of renal colic Unilateral flank tenderness (unreliable) No peritonism Signs of complications Fever, dehydration Differential diagnoses Pyelonephritis, appendicitis, diverticulitis, salpingitis, ectopic pregnancy, AAA, testicular torsion, herpes zoster, biliary disease, renal cell carcinoma Signs of renal colic is unexciting – patient writing in bed Differentials: appendicitis, diverticulitis, salpingitis, pyelonephritis, ruptured AAA, testicular torsion

Investigation Lucent Opaque Pathology In all – UEC, FBE, urine dipstick/MC&S, BhCG In some – ionised calcium, uric acid, PTH, urinary products Imaging Plain XR CTKUB Renal tract ultrasound Intravenous pyelogram Who to image – first time presentation Lucent Opaque Urate Calcium oxalate/phosphate Cystine Struvite

When to call Urology? Does surgery need to be considered? Complicated vs. Uncomplicated Large stone Bilateral stones with obstruction Evidence of shock or infection Acute renal impairment Anuria/oliguria Solitary kidney, transplanted kidney Pregnancy Key question whenever calling a surgeon

Medical management Analgesia NSAIDs (diclofenac, indomethacin) and opiates are roughly equivalent, can use both Anti-emesis Medical expulsive therapy Tamsulosin (alpha-antagonist) Oral chemolysis Antibiotics for infection Prevention Allopurinol for urate stones, dietary restriction of calcium/oxalate Consider renal impairment in use of NSAIDS Nifedipine is alternative to tamsulosin Oral chemolysis: sodium bicarbonate to alkalinise urine

Wait and watch Spontaneous expulsion Serial imaging, urine straining Size of stone (mm) Rate of expulsion 1 87% 2-4 76% 5-7 60% 7-9 48% >9 25% Other consideration is the days it takes to pass Serial imaging, urine straining Symptom management Monitor for complications

Surgical management Non-invasive approach External shock wave lithotripsy Incisional approach Percutaneous lithotomy Open/laparoscopic surgery Endoscopic approach Ureteroscopy and basket Ureteric stent placement Considerations: size of stone, location of stone, complications, type of patient, type of stone

Review Common ED presentation Clues on history and examination Confirmation with investigation Complicated vs. Uncomplicated Call Urology Consider medical as well as surgical Mx Should be considered and excluded in all presentations of abdominal, back and groin/scrotal pain