Urology - calculi

Question 1

proper name for renal calculi?

Answer 1

nephrolithiasis

Question 2

where classically deposited? (3)

Answer 2

1) pelviureteric junction
2) pelvic brim
3) vesicoureteric junction

Question 3

peak demographic + age?

Answer 3

20-40 yr old men

Question 4

different presentations of calculi?

6

Answer 4

(ASx)

1) renal colic/renal obstruction/mid-ureter obstruction/lower ureter obstruction/bladder/urethra obstruction
2) UTI/ pyelonephritis/pyonephritis (infected hydronephrosis)
3) haematuria
4) proteinuria
5) sterile pyuria
6) anuria

Question 5

“renal colic” Sx?

Answer 5

excruciating ureteric spasms
"loin to groin"
(or genitals/inner thigh)
\+ N/V
cannot lie still (ΔΔ from peritonitis)

Question 6

“renal obstruction” Sx?

Answer 6

felt in loin

between rib 12 and lateral edge of lumbar muscles

Question 7

“mid-ureter obstruction” Sx?

Answer 7

mimics appendicitis/diverticulitis

Question 8

“lower ureter obstruction” Sx?

Answer 8

bladder irritability

pain in scrotum/penile tip/labia majora

Question 9

“bladder/urethra obstruction” Sx?

Answer 9

pelvic pain
dysuria
strangury (desire but inability to void)
+/- interrupted flow

Question 10

renal calculi Ex?

Answer 10

usually no tenderness on palpation
+/- renal angle tenderness
(especially to percussion if retroperitoneal inflammation)

Question 11

Ix renal calculi?

Answer 11

Bloods
- FBC, U+E, Ca2+, Po4, glucose, HCO3, urate
Dipstick
- +ve for blood 90%
MSU
- MC+S
Further tests
- Urine pH
- 24hr urine (Ca2+, oxalate, urate, citrate, Na+, creatinine
- stone biochemistry (sieve urine + send stone)
IMAGING
- spiral non-contrast CT 99% (ΔΔ acute abdo - AAA similar)
- 80% KUB XR
- USS for hydronephrosis/hydroureter

Question 12

Tx renal calculi?

Answer 12

Analgesia (diclofenac)
IV fluids (stones <5mm 90% pass)
Abx (cefuroxime/gentamicin)
Medical expulsion therapy (nifedipine/tamsulosin, if stones >5mm/not passing)

Most pass w/n 48hrs

If not, try extracorporeal shockwave lithotripsy (ESWL) (USS waves shatter stone <1cm)
Or, ureteroscopy using basket.
Or eventually, percutaneous nephrolithotomy (PCNL)

Question 13

S/E ESWL?

Answer 13

renal injury

increased BP + DM

Question 14

indications for urgent intervention?

Answer 14

infection AND obstruction
urosepsis
intractable pain/V
impending acute
obstruction in solitary kidney
bilateral obstructing stones

Question 15

urgent intervention Tx?

Answer 15

percutaneous nephrotomy or ureteric stent

Question 16

prevention for stones?

Answer 16

fluids
normal Ca2+ intake
thiazide (if Ca2+ stones, thiazide ↓ hypercalciuria)
pyridoxine + diet (oxalate stones, found in choc, tea, rhubarb)
allopurinol + alkalisation (urate)
hydration + alkalisation + D-penicillamine (cysteine)