Nephrology: Nephrolithiasis Flashcards
1
Q
Incidence
A
1- 5 percent
2
Q
Etiology
A
- calcium oxalate 70%
- (anything that increases calcium absorption in gut, anything that decreases oxalates in Gi)
- calcium phosphate - 10%
- mg/aluminum/phosphate (struvite)- 5-10% (infections, proteums)
- uric acid stones are radiolucent - 5%
- cystein - 1%
- indinavir - protease inhibitor 4% will get stones
3
Q
hypercalciuria
A
- Vit D intoxication
- increased Vitamin D with sarcoidosis and other granulomatous disease
- hyperparathyroidism
- increased urinary calcium secretors is most common
- most common cause of high calcium in serum is hyperparathyroidism
4
Q
Hyperoxaluria
A
- fat binds with calcium in GI
- “soft soap”
- fat malabsorption, fat binds with calcium, so increased oxalate resorption, and therefore more in the urine
- envelope shaped crystals (also see this is suicide attempt - ethylene glycol - do urinalysis first in suicide attempts - will also give increased anion gap metabolic acidosis)
5
Q
Calcium citrate stones
A
- citrate - from RBC units, citrate binds up the calcium. lots of units transfused can therefore cause seizure
- low citrate causes increased calcium absorption, and induced by acidosis
- forms in basic urine
6
Q
Uric acid stones
A
- form in acidic urine - only one
- etiology: gout, leukemia, chron disease
- radiolucent (no calcium)
7
Q
Csystinuria
A
- genetic only
8
Q
struvite stones
A
- proteus infections increase pH, leading to struvite stones (calcium/mg/oxalate)
9
Q
stones - presentation
A
constant, flank pain radiating to the groin
hematuria
best first thing is pain meds - ketolorac
Dx: plain x-ray (first test, misses 10%) ultrasound (first in office setting) strain the urine serum and urine calcium IV pyelogram (* NEVER) Helical CT without contrast (most accurate)
10
Q
management
A
< 5mm - will pass spontaneously
> 5mm and < 2cm - lithotripsy
> 2cm, surgical (place lithotripsy directly on the stone inside the kidney)
