Stones

Question 1

Types

Answer 1

Calcium oxalate: most common and are radio opaque on AXR

Struvite (stag-horn and infected urine)

Urate (occurs with high cell turn over e.g. chemotherapy)

Cysteine (occurs in metabolic conditions)

Question 2

Clinical features

Answer 2

Renal colic (loin to groin)

LUTS- storage vs voiding

Haematuria

Nausea and vomiting

Question 3

Investigation

Answer 3

Urine dip

Blood - FBC (WCC), U+Es

Gold standard: non contrast CTKUB but could do US KUB in child

Question 4

Management

Answer 4

Stone <5mm = conservative: analgesia, passes spontaneously

5-10mm = nifedipine or tamsulosin to relax smooth muscle

> 10mm or obstruction or renal impairment or stones that haven’t passed within 6 hours:

• shockwave lithotripsy if <20mm (Never use in pregnant woman)
• hydronephrosis needs cystoscope and stent
• stone being proximal to kidney (e.g. struvite staghorn calculus) then ureteroscopy to laser/ fragment stone
• very large stone (>20mm) needs percutaneous nephrolithotomy

Question 5

What is percutaneous nephrolithotomy?

Answer 5

Performed in theatres under anaesthetic

A nephroscope (small camera on a stick) is inserted via a small incision at the patient’s back

The scope is inserted through the kidney to assess the ureter

Stones can either be removed or broken up to small stones