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Flashcards in Urostones Deck (20):
1

What are the risk factors for developing urostones?

Intrinsic
- male
- genetics
- metabolic
- medical conditions (hyperthyroid, malabsorption, drugs, sarcoidosis)
Extrinsic
- climate
- occupation
- fluid intake
- diet

2

How are bladder stones formed?

Under-saturated
Supersaturated byt stable - metastable
Supersaturated with spontaneous precipitation - unstable

3

What are the saturation and formation products?

Saturation product - level at which no more solute will dissolve without a change in pH or temperature
Formation product
- level at which spontaneous formation occurs

4

What is the free-particle model of stone formation?

Urine containing crystals flows down the collecting ducts
Crystals grow and agglomerate
A critical particle gets trapped in the tubule

5

What is the fixed-particle model of stone formation?

Urine containing crystals flows down the collecting ducts
Crystals grow and agglomerate
Particle adheres to the damaged site on the tubule wall and other crystals agglomerate with it

6

Name some stone inhibitors.

Citrate
Magnesium
Pyrophosphate
Glycoproteins

7

Name some stone promoters.

THP
Matrix substance A

8

What factors affect stone formation?

Decrease liklihood of stone formation
- Low volume
- Low pH
- Low citrate
- Low magnesium
Increase stone formation
- high uric acid
- high calcium
- high oxalate

9

What types of stones occur in the bladder?

Calcium stones (80%)
- calcium oxalate monohydrate
- calcium phosphate
Infection stones (10%)
- struvite
Uric acid stone (5%)
- not seen on X-Ray
Others (1%)
- cysteine, silica

10

How do bladder stones present?

Incidental
- imaging being done for a different reason
Pain
- colic, radiates from loin to groin, can't settle and unable to stay still
Haematuria
- visible or non-visible
Sepsis/infection

11

What initial investigation are done if you suspect bladder stones?

History and examination
Bloods
- CRP, FBC, U&Es
Urine
- non-visible haematuria (85%)
Imaging
- CT KUB (non-contrast) is best

12

What biochemical workup would you do if someone presented with their first stone?

U&Es
Calcium
Urate
Urine dip
Sodium nitroprusside (cysteine)
Stone analysis

13

What biochemical workup would you do if someone presented with a recurrent stone?

U&Es
Calcium
Urate
Venous bicarbonate
24 hour sodium urine analysis

14

How are stones managed?

Passing naturally
- <4mm 75% chance
Medical therapy
Surgical therapy

15

Describe the medical therapy for bladder stones.

Analgesia
- NSAIDs reduce pain due to reduced GFR, renal pressure and ureteric peristalsis
Medical expulsion therapy
- possibly

16

What are the surgical options for bladder stones?

Ureteroscopy and basket
Ureteroscopy and fragmentation
Flexible ureteroscopy
ESWL - extracorporeal shockwave lithotripsy
PCNL - percutaneous nephrolithotomy
Emergency stent

17

What is a ureteroscopy?

Best for ureteric stones or renal <2cm
Can be rigid or flexible
Basket, laser and lithoclast
General anaesthetic

18

What is percutaneous nephrolithotomy?

Best for stones larger than 2cm in the kidney
Direct access to the kidney via the skin to fragment or extract the stones
General anaesthetic

19

What is extracorporal shockwave lithotripsy?

Best for proximal ureteric stones <10mm or renal stones <2cm depending on the location
Generation of shockwaves externally to break up the stones
Requires analgesia

20

How are infected obstructed systems delt with?

Sepsis 6
Culture and Abx
Imaging CT or USS
Urgent decompression of an obstructed infected collecting system
- nephrostomy
- ureteric stenting