Ureteric Stones

Question 1

Urolithiasis

Answer 1

Ureteric stones

Question 2

Common sites for urolithiasis

Answer 2

• Pelviureteric junction
• Crossing the iliac vessels at the pelvic brim
• Vesicoureteric junction

Question 3

Pathophysiology of urolithiasis

Answer 3

• ↑ concentration of urinary solute
• ↓ urine volume
• Urinary stasis

Question 4

Stone Types

Answer 4

• Calcium oxalate: 75%
- ↑ risk in Crohn’s

• Triple phosphate (struvite) - proteus infection (stag horn calculus)

• Urate (radiolucent)
- Gout

• Cystine

Question 5

RF for urolithiasis

Answer 5

• Dehydration
• Hypercalcaemia: secondary to hyper-parathyroid or immobilisation
• ↑ oxalate excretion: tea, strawberries
• UTIs
• Hyperuricaemia: e.g. gout
• Urinary tract abnormalities: e.g. bladder diverticulae
• Drugs: furosemide, thiazides

Question 6

Presentation of urolithiasis

Answer 6

Ureteric Colic:
• Severe, sudden onset loin to groin pain 
- can radiate to thigh 
• N+V
• Pt. cannot lie still
• Haematuria - non visible

Bladder or Urethral Obstruction:
• Bladder irritability: frequency, dysuria, haematuria
• Strangury: painful urinary tenesmus
• Suprapubic pain radiating → tip of penis or in labia
• Pain and haematuria worse at the end of micturition

Question 7

Associated features with urolithiasis

Answer 7

• UTI
• Haematuria
• Sterile pyuria
• Anuria

Question 8

Investigations of urolithiasis

Answer 8

Urine
• Dip: haematuria
• MC+S

Blood
• FBC, U+E, Ca, PO4, urate

Imaging
Non-contrast CT-KUB - Gold standard
• 99% of stones visible

KUB XR
• 90% of stones radio-opaque
• Urate stones are radiolucent, cysteine stones are faint

USS: hydronephrosis
Non contrast CT KUB - gold standard

Question 9

Preventing ureteric stones

Answer 9

• Fluids
• Treat UTIs rapidly
• ↓ oxalate intake: chocolate, tea, strawberries

Question 10

Mx of urolithiasis

Answer 10

• Analgesia - IM diclofenac
• Fluids
• Abx if infection: e.g. cefuroxime

Conservative: <5mm in lower 1/3 of ureter

• pass spontaneously - discharge pt. ¯c analgesia
• Sieve urine to collect stone for analysis

Question 11

When is medical expulsive therapy given (MET)

Answer 11

• Stone 5-10mm

* Stone not expected to pass

Question 12

MET - medical expulsion therapy

Answer 12

• Nifedipine or tamsulosin
• ± prednisolone
• Most pass w/i 48h

Question 13

Indications for active stone removal

Answer 13

• Low likelihood of spontaneous passage: >10mm
• Persistent obstruction
• Renal insufficiency
• Infection

Question 14

Stone Removal procedures

Answer 14

Extracorporeal Shockwave Lithotripsy - Stones <20mm in kidney or proximal ureter

Flexible Ureterorenoscopy - laser lithotripy

Percutaneous
Nephrolithotomy - Stone >20mm in renal pelvis

Question 15

Contraindications for extracorporeal shockwave lithotripsy

Answer 15

Pregnancy
AAA
Bleeding diathesis
Stone over bony landmark e.g. pelvis

Question 16

Febrile with Renal Obstruction

Answer 16

• Surgical emergency
• Percutaneous nephrostomy or ureteric stent
• IV Abx: cefuroxime

Question 17

Cystine stones

Answer 17

Associated with homocysteinuria

• inherited defect

Question 18

Criteria for Inpatient Admission

Answer 18

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

Question 19

Retrograde stent insertion

Answer 19

Placement of a stent within the ureter, approaching from distal to proximal via cystoscopy

Question 20

Nephrostomy

Answer 20

Tube placed directly into the renal pelvis and collecting system, relieving the obstruction proximally

Question 21

Recurrent bladder stone complications

Answer 21

SCC bladder cancer

Question 22

Removal of stone if pregnant

Answer 22

Flexible ureto- renoscopy

Question 23

Mx if septic - infected obstructed stone

Answer 23

Sepsis 6

Nephrostomy - unstable

Question 24

Renal cyst on CT

Answer 24

Clear before and after contrast

Smooth and well defined