Urolithiasis

Question 1

What substances can renal + ureteric stones be made from?

Answer 1

1. Calcium oxalate (75%)
2. Calcium phosphate
3. Urate (uric acid)
4. Struvite
5. Cystiene

Question 2

Where in the ureter do stones tend to lodge?

Answer 2

In the narrow regions

• Ureteropelvic junction
• Passes over pelvic brim
• Vesicoureteric junction

Question 3

Clinical features of renal + ureteric calculi?

Answer 3

Intense, sudden loin to groin colicky pain
Caused by dilatation, spasm of ureter

Pain radiates to scrotum or labia

Loin tenderness

Macroscopic haematuria

Urinary retention
Dysuria

Fever, rigors, nausea alerts you to the possibility of pyelonephritis secondary to stone

Question 4

Investigation of renal + ureteric calculi?

Answer 4

Bedside:

• obs
• BM
• Urine dip for haematuria, infection, pH

Routine:

• Bloods: FBC, UE, LFT, CRP, calcium and urate levels
• Urine MC+S
• AXR (75% stones are radio-opaque)

Specialist:
- CT KUB

Question 5

What special blood tests should you do if you suspect renal + ureteric calculi?

Answer 5

Urate
Calcium

If these are raised it would further suspicions there is a stone

Question 6

What proportion of stones are visible on AXR?

Which ones are and aren’t?

Answer 6

75% are radio-opaque
Calcium stones are
Cystine stones aren’t

Question 7

Management of renal + ureteric calculi?

Answer 7

NSAIDs: diclofenac IM or PR
anti-emetics
Rehydration

Less than 5mm stones are left for patient to pass, while giving strong analgesia and plenty of fluids

Over 5mm
Medical: Ca channel blockers, alpha blocker (tamsulosin)

Surgical management

Antibiotics if signs of pyelonephritis

Question 8

Complications of urolithiasis?

Answer 8

Urinary flow obstruction, which reduces GFR, irreversible damage if more than 48hrs

Infection: pyonephrosis

Question 9

Describe the surgical options available to manage renal + ureteric calculi?

Answer 9

Lithotripsy: high energy shock waves passed through body to break up stones into small pieces which can then be passed (complications: hypertension, diabetes)

Percutaneous nephrolithotomy: guidewire insterted into renal pelvis through which instruments can be used to visualise and break up stone

Question 10

What is a nephrostomy?

Answer 10

A tube that goes percutaneously into the renal pelvis to drain urine

When there is a blockage in ureter

Question 11

Long term management of patients with recurrent stones?

Answer 11

Increase daily fluid intake

Lemon juice in water

Reduce meat intake

Reduce refined sugar

Reduce salt intake

Drugs:

• allopurinol for uric acid stones
• thiazide diuretics for calcium stones
• calcium citrate for oxalate stones

Question 12

Risk factors for urolithiasis?

Answer 12

Anatomical anomalies
Family history
Hypertension
Gout
Hyperparathyroidism
Immobilisation
Dehydration
Hot climates