FN: Urolithiasis: Ix and Mx

Question 1

Urine shows

Answer 1

Haematuria

MC+S

Question 2

Blood look at

Answer 2

FBC
U+E
Ca
Po4
urate

Question 3

Imaging

Answer 3

KUB XR
USS
Spiral non-contrast CT-KUB
IVU
Functional scans

Question 4

KUB XR

Answer 4

• 90% of stones radio-opaquw

- Urate stones are radiolucent, cysteine stones are faint

Question 5

USS shows

Answer 5

Hydronephrosis

Question 6

Spiral non-contrast CT-KUB

Answer 6

• 99% of stones visible

- Gold standard

Question 7

IVU

Answer 7

• 600x radiation dose of KUB

- IV contrast injected and control, immediate and serial films taken until contrast @ level of obstruction

Question 8

IVU abnormal findings

Answer 8

• failure of flow to the bladder
• standing column of contrast
• clubbing of the calyces: back pressure
• delayed, dense nephrogram: no flow from kidney

Question 9

IVU CI

Answer 9

• contrast allergy
• Severe asthma
• Metformin
• Pregnancy

Question 10

Functional Scans

Answer 10

DMSA: dimercaptosuccinic acid
DTPA: diethlenetriamene penta-acetic acid
MAG-3

Question 11

Prevention

Answer 11

Drink plenty
Treat UTIs rapidly
Reduced oxalate intake: chocolate, tea, strawberries

Question 12

Initial Rx

Answer 12

Analgesia

• Diclofenac 75mg PO/IM or 100mg PR
• Opiods if NSAIDS CI: e.g. pethidine

Fluids: IV if unable to tolerate PO
Abx: if infection: e.g. cefuroxime 1.5mg IV TDS

Question 13

Conservative Mx

Answer 13

• 90-95% pass spontaneously
• Can discharge pt. with analgesia
• Sieve urine to collect stone for OPD analysis

Question 14

Medical expulsive therapy indications

Answer 14

stone 5-10mm

Stone expected to pass

Question 15

Drugs for expulsion

Answer 15

Nifedipine or tamsulosin
± prednisolone
Most pass with 48h, 80% w.i 30 d

Question 16

Active stone removal indications

Answer 16

• low likelihood of spontenous passage e.g. >10 mm
• persistent obstruction
• renal insufficiency
• infection

Question 17

Extracorporeal shockwave lithotripsy

Answer 17

• stones

Question 18

Ureteroenoscopy (URs) + domier basket removal

Answer 18

• Stone >10mm in distal ureter or if SWL failed

Stone > 20 mm in renal pelvis

Question 19

Percutaneous nephrolithotomy (PNL)

Answer 19

Stone >20mm in renal pelvis

e.g. staghorn calculi do DMSa first

Question 20

Febrile with renal osbtruction

Answer 20

Surgical emergency
Percutaneous nephrostomy or ureteruc stent
IV abx e.g. cefuroxime 1.5g IV TDS

Question 21

Rx summary

Answer 21

Conservative: stone