Urinary tract calculi Flashcards
What are urinary tract calculi?
presence of calculi within the urinary system
Where are 3 common points to find urinary tract calculi?
- Ureteropelvic junction
- Pelvic brim (where ureters cross the iliac vessels)
- Ureterovesical junction
What is the most common type of stone?
- Calcium oxalate
What are the other types of stones?
- Struvite (magnesium ammonium phosphate)
- Urate/uric acid - 5% - not visible on X-ray!
- Hydroxyapatite (5%)
What is the patho of urinary tract calculi?
Urinary solutes are highly concentrated so supersaturate and precipitate out of solution
What can cause urinary tract calculi?
Anything that can cause an increase in:
- Calcium
- Uric acid
- Oxalate
- Sodium
What are the metabolic causes for urinary tract calculi?
- Hypercalcaemia
- Hyperuricaemia
- Hypercystinuria
- Hyperoxaluria
- Hypocitraturia
- Hyperparathyroidism
- Renal tubular acidosis
What are the infective causes for urinary tract calculi?
- Hyperuricaemia
- Recurrent UTIs
- Chronic UTI
What drugs can cause urinary tract calculi?
- Indinavir, atazanavir
- Diuretics
- Antacids (Ca-containing)
- Carbonic anhydrase inhibitors
- Na- and Ca-containing medications
- Vit C+D
- Corticosteroids
What are other causes of obstruction?
- urinary tract abnormalities
2. foreign bodies (stents, catheters)
What urinary tract abnormailites can use urinary tract calculi?
o Pelviureteric junction obstruction
o Hydronephrosis
o Ureteral stricture
What are RF for urinary tract calculi?
- Dehydration
- High protein intake
- High salt
- Structural abnormalities
- PMHx
- FHx
What is the common epi for urinary tract calculi?
- 3x more common in MALES
- Age group: 30-50yrs
- Higher prevalence in hot, dry countries
What are the initial symptoms of urinary tract calculi?
asymptomatic
What are the symptoms of urinary tract calculi as they get stuck?
- Acute severe loin to groin pain = renal colic
- N and V
- Unable to lie still/writhing in pain
What are the urinary symptoms?
- Urgency
- Frequency
- Haematuria (85% microscopic, occasional macroscopic)
What are the bedside investigations for urinary tract calculi?
1st line: urine dipstick
NOTE: in all women of child-bearing age do pregnancy test to exclude ectopic pregnancy
What bloods are done?
- FBC
- WBC for UTI
- U&Eās, Cr, Ca to check renal function
What imaging is done?
GOLD STANDARD: non- contrast CT-KUB or (USS in pregnant) - kidney stones show up white
What is the acute management for urinary tract calculi?
- Fluids
- Analgesia (diclofenac)
- Anti-emetics (ondansetron)
- Urine collection - collect passed stone
What is the management for urinary tract calculi when <5mm?
leave to pass spontaneously with increased fluid intake
What is the management for urinary tract calculi when <10mm?
- alpha-blocker (tamsulosin)
2. if not passed after 4-6 weeks: surgery
What is the management for urinary tract calculi when >10mm or failed therapy?
-surgical removal
1st line: extracorporeal shock wave lithotripsy (ESWL)
2. Percutaeneous nephrostolithotomy ā difficult shape stone e.g. staghorns
What is ESWL?
- A scope is passed into the bladder and up the ureter to visualise the stone
- AN electromagnetic wave is then focus onto the calculus to break it up into smaller fragments that can pass spontaneously
What is PCNL?
key hole surgery
What are possible complications of urinary tract calculi?
- Pyelonephritis
- Septicaemia
- Obstruction
- Urinary retention
- Hydronephrosis, AKI
What is a rare cause of kidney stones?
cystinuria
Why do you need to be careful with renal colic?
- Common but several DDx
1. AAA
2. Biliary colic
3. Constipation
4. Bowel obstruction
5. Ectopic preggers - Dipstick haematuria
- Must confirm with CT/KUB
