Renal tract calculi

Question 1

Define Renal tract stones (urolithiasis)

Answer 1

Hard, mineral-based mass that forms anywhere in the urinary tract

Question 2

Types of renal calculi

Answer 2

1. Calcium: calcium oxalate, calcium phosphate
2. Struvite: Magnesium ammonium phosphate
3. Urate: uric acid (radiolucent stones - NOT appear on X-rays)
4. Cystine: assoc. familial disorder

Question 3

which type of the calculi is the largest

Answer 3

Struivite calculi

Question 4

what causes struvite stones

Answer 4

AKA infection stones
- form in alkalina urine
- urease-producing organisms Proteus / Klebisella bacteria
- forms Magnesium ammonium phosphate stones

Question 5

Renal tract stone gold standard imaging Ix

Answer 5

non-contrast CT KUB

Question 6

Cystine stone CT appearance

Answer 6

semi-opaque stone with a ‘ground-glass’ appearence

Question 7

what type of renal stone is chemo patient likely to have

Answer 7

Urate: rapid cell turnover –> hyperuraemic

Question 8

Renal tract stone 1st line analgesia

Answer 8

PR / IM NSAIDs

Question 9

what medication is prescribed to prevent cystine stone

Answer 9

Penicillin

Question 10

Extracorporeal Shock Wave Lithotripsy (ESWL) contraindication

Answer 10

1. In pregnant women
2. patient who are on anticoag / coagulapathy ** (e.g. haemophilia)**
3. stones >2cm

Question 11

CCCS

Radio-opaque (appears white on X-ray) stones

Answer 11

1. Calcium oxalate
2. Calcium Phosphate
3. Cystine Stones
4. Struvite Stones

Question 12

Radio-lucent (not showing on X-ray) stones

Answer 12

1. Uric acid stones

Question 13

stone removal procedure of choice for pregnant women

Answer 13

Flexible uretero-renoscopy (Ureteroscopic stone removal)

URS

Question 14

Extracorporeal Shock Wave Lithotripsy (ESWL) indications

Answer 14

1. stones <2cm
2. evidence of obstructing stones

Question 15

How Extracorporeal Shock Wave Lithotripsy (ESWL) work

Answer 15

• Uses sonic waves to break up the stone
• stone passess spontaneously
• under Xray / US guidance

Question 16

Percutaneous nephrolithotomy (PCNL) indications

Answer 16

1. Renal stones ONLY
2. large stones >2cm

Question 17

Conservative Mx for renal stones

Answer 17

1. Increase fluid intake (reduced coffee, tea, alcohol)
2. Reduce animal protein (meat / fish)
3. Reduce oxalate food (coffee, nuts, soya, spinach)
4. Reduce sodium intake (5-6g)

Question 18

what Ix should be done on all patients who has had renal stones

Answer 18

1. U&Es (renal func.)
2. Uric acid levels
3. Calcium levels

Question 19

what Ix should be done on high-risk stone formers

Answer 19

TWO 24h urine samples

Question 20

Advice on preventing urate stones

Answer 20

1. Reduced purine rich foods (animal protein, yeast extract, beer)
2. Weight loss for overweight patients
3. Good control of DM

Question 21

Renal tract stone admission criteria

Answer 21

1. Post-obstructive acute kidney injury
2. Uncontrollable pain from simple analgesics
3. Evidence of an infected stone(s)
4. Large stones (>5mm)

Question 22

Typical presentation of renal tract stones

Answer 22

1. “loin to groin pain”
2. colicky pain “comes and goes in waves”
3. haematuria
4. N + V

Question 23

Most common type of renal tract stone

Answer 23

Calcium oxalate

Question 24

At what size, stones is unlikely to pass spontaneously

Answer 24

• > 5mm