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

2. 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

3. “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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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