Renal and Ureteric Stones Flashcards
1
Q
What is urolithiasis?
A
- Stone disease
- Common disorder where stones form in kidney or bladder but may present anywhere in urinary tract
- While stones often cause pain at some point, many can remain asymptomatic
- Affect 1-5% of population, with Caucasian men being particularly affected
2
Q
Where do stones commonly get stuck?
A
- Pelvic-ureteric junction
- Pelvic brim
- Vesico-ureteric junction
3
Q
Stones are usually idiopathic with low fluid intake promoting stone formation, but what else can they be associated with?
A
- Metabolic → hyperparathyroidism / prolonged immobilisation / gout
- Dietary → high oxalate from tea, nuts, choc, strawbs
4
Q
What type of stones are renal stones?
A
- Calcium oxalate (65%) → spiky, radio-opaque
- Calcium phosphate (15%) → smooth, large, radio-opaque
- Struvite (10-15%) → large, horny, staghorn, radio-opaque
- Urate (3-5%) → smooth, brown, radiolucent
- Cystine (2%) → yellow, crystalline, semi-opaque
5
Q
What are clinical features of stones?
A
- Ureteric colic → loin-grain pain, may radiate to testes/labia, is the acute presentation, where ureteric smooth muscle contracts against the blocked stone causing colic; intense and agonising
- Microscopic haematuria → occurs >90% pts
- Gravelly urine → small stones pass painlessly in urine
- UTI → recurrent cystitis or pyelonephritis
6
Q
Which bedside investigations for renal stones?
A
Urine dipstick → identifies UTI and haematuria
7
Q
Which blood tests for renal stones?
A
- FBC
- U+Es
- Calcium
- Phosphate
- Uric acid
- Clotting
8
Q
What is the 1st line choice of imaging for stones?
A
- Non-contrast CT KUB
- 99% visible
- Helps to exclude other causes
Can also do IV urogram to outline urinary tract and show function and any obstruction or hydronephrosis
9
Q
What is the acute management for stones?
A
- Pain relief by NSAIDs (eg. diclofenac)
- An obstruction, particularly if infection present, is a urological emergency
- Must be relieved to prevent permanent renal damage
-
Percutaneous nephrostomy
- A small tube passed into upper renal pelvis (under US guidance w/ the patient sedated), and the urine collected in an external bag
10
Q
What is the non-emergency management of stones?
A
- < 5mm → will pass within 4-6 wks
- If complicated (ureteric obstruction, renal developmental abnormality, prev renal transplant) then intervention
- Extracorpeal shockwave lithotripsy (ESWL) → non-invasive procedure used in > 80%; shockwaves focused using USS guidance onto the stone, which is fragmented and passed during micturition
- Ureteroscopy → passed via urethra to retrieve stones using collecting baskets, or to fragment them with intracorporal lithotripsy or lasers
- Percutaneous nephrolithotomy → tract formed via small loin incision directly from loin into renal pelvis + nephroscope inserted, stone retrieved with basket or fragmented - technique useful for large stones or staghorn stones in pelvis
11
Q
Who can’t undergo lithotripsy?
A
- Pregnant women
- Those taking warfarin
12
Q
Are stones likely to recur?
A
- Recur in 50% of pts
- Advise high fluid intake to produce >2L urine per day
- Avoid foods with high oxalate content
- Manage hypercalcaemia w/ thiazides
- Gout is managed with allopurinol