9 - Renal Stones

Question 1

How are different stones in the urinary tract classified?

Answer 1

- Staghorn if filling numerous major and minor calices

- Non-staghorn can be calyceal or pelvic

- Ureteral are proximal, middle or distal

Question 2

What measurements does a kidney stone have to be to require intervention?

Answer 2

- Less than 5mm high chance of being passed

• 5 to 7mm 50% chance of being passed

- Over 7mm require intervention

Question 3

What are some symptoms of kidney stones?

Answer 3

• Renal colic (flank pain) as stone makes passage down urinary tract

Question 4

What are some ways of surgically removing kidney stones?

Answer 4

• Ureteroscopy with laser
• Percutaneous Nephrolithotomy (PCNL)
• Shock wave lithotripsy

Question 5

What is the composition of different types of kidney stones?

Answer 5

- Calcium Oxalate and Calcium Phosphate (80%)

• Uric acid (9%)
• Struvite (10% - bacteria infection with urease enzyme)
• Drugs, cystine, ammonium acid urate (1%)

(composition due to supersaturation in urine at time of formation)

Question 6

What is the aetiology of renal calculi?

Answer 6

• Hypercalcuria
• Urinary infection with pseudomonas, klebsiella
• Diet high in table salt
• Furosemide
• Cystinuria
• Ketogenic diet

Question 7

How do we diagnose urolithiasis and what are some differentials?

Answer 7

- Loin to groin pain and haematuria

• CT
• Ultrasound
• Ruptured AA, pancreatitis, appendicitis

Question 8

How do we treat urate stones?

Answer 8

Usually can be treated by alkalinisation

Question 9

How does electric shock wave lithotripsy work for renal calculi and how can you tell if this method will work?

Answer 9

• If less than 2cm and can be localised with imaging you can us this technique
• Can’t use if in lower pole calyx

Question 10

What is cystinuria and what does it predispose to?

Answer 10

Autosomal recessive, high concentrations of cysteine in urine, leading to the formation of cystine stones in the kidneys, ureter, and bladder

Usually why paeds have calculi

Question 11

What should you do before performing a PCNL?

Answer 11

DMSA split function to check the kidney is working so not wasting time

Question 12

When would we see ketonuria?

Answer 12

• Diabetic individuals
• Febrile illness
• Cachexia

Question 13

What are some promoters and inhibitors of kidney stones?

Answer 13

Question 14

How can we prevent someone from getting recurring kidney stones?

Answer 14