Ureteric Stones Flashcards
Urolithiasis
Ureteric stones
Common sites for urolithiasis
- Pelviureteric junction
- Crossing the iliac vessels at the pelvic brim
- Vesicoureteric junction
Pathophysiology of urolithiasis
- ↑ concentration of urinary solute
- ↓ urine volume
- Urinary stasis
Stone Types
• Calcium oxalate: 75%
- ↑ risk in Crohn’s
• Triple phosphate (struvite) - proteus infection (stag horn calculus)
• Urate (radiolucent)
- Gout
• Cystine
RF for urolithiasis
- 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
Presentation of urolithiasis
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
Associated features with urolithiasis
- UTI
- Haematuria
- Sterile pyuria
- Anuria
Investigations of urolithiasis
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
Preventing ureteric stones
- Fluids
- Treat UTIs rapidly
- ↓ oxalate intake: chocolate, tea, strawberries
Mx of urolithiasis
- 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
When is medical expulsive therapy given (MET)
- Stone 5-10mm
* Stone not expected to pass
MET - medical expulsion therapy
- Nifedipine or tamsulosin
- ± prednisolone
- Most pass w/i 48h
Indications for active stone removal
- Low likelihood of spontaneous passage: >10mm
- Persistent obstruction
- Renal insufficiency
- Infection
Stone Removal procedures
Extracorporeal Shockwave Lithotripsy - Stones <20mm in kidney or proximal ureter
Flexible Ureterorenoscopy - laser lithotripy
Percutaneous
Nephrolithotomy - Stone >20mm in renal pelvis
Contraindications for extracorporeal shockwave lithotripsy
Pregnancy
AAA
Bleeding diathesis
Stone over bony landmark e.g. pelvis
Febrile with Renal Obstruction
- Surgical emergency
- Percutaneous nephrostomy or ureteric stent
- IV Abx: cefuroxime
Cystine stones
Associated with homocysteinuria
- inherited defect
Criteria for Inpatient Admission
- Post-obstructive acute kidney injury
- Uncontrollable pain from simple analgesics
- Evidence of an infected stone(s)
- Large stones (>5mm)
Retrograde stent insertion
Placement of a stent within the ureter, approaching from distal to proximal via cystoscopy
Nephrostomy
Tube placed directly into the renal pelvis and collecting system, relieving the obstruction proximally
Recurrent bladder stone complications
SCC bladder cancer
Removal of stone if pregnant
Flexible ureto- renoscopy
Mx if septic - infected obstructed stone
Sepsis 6
Nephrostomy - unstable
Renal cyst on CT
Clear before and after contrast
Smooth and well defined