L21: Cases Flashcards
Nephrolithiasis is due to
supersaturation of urine leading to crystal formation
Crystals can be
Calcium oxalate
Calcium phosphate
Struvite
Uric acid
Crystine
Struvite means
Magnesium ammonium phosphate
Uric acid crystals are
radiolucent
Risk factors for nephrolithiasis
History/family history Decreased fluid intake Malabsorption causing increased urinary oxalate excretion Hyperparathyroidism DM Gout Obesity Marathon running
How often do stone recur?
1/3 recur within 4 years
What might cause malabsorption, causing increased urinary oxalate excretion?
Bariatric surgery
Imaging of choice for nephrolithiasis
Non-contrast CT abdomen/pelvic
Why isn’t contrast used for nephrolithiasis diagnosis?
Decreases sensitivity for small stones
Perinephritis stranding on CT
a sign of inflammation/obstruction
Ultrasound+nephrolithiasis
less sensitive. may need follow up CT
Is IV pyelogram recommended for detection of stones?
NO
Treatment of kidney stones: symptomatic
NSAIDS
Opiates
Hydration
Strain urine to catch ya stone
If a stone is strained from urine or surgically removed….
send it off for composition analysis
Stones <5 mm….
Usually pass spontaneously
Stones >20 mm….
refer to urology
Stones tx to relax smooth muscle around urinary tract
Tamsulosin .4 mg qd
alpha 1 blocker
If your patient has a uric acid stone
Gout tx: allopurinol
Optional tx for stones
HCTZ diuretic increases Ca++ absorption, can prevent future stones
Prevention of stones
Increase hydration
Decrease sodium
You patient fails to pass the stone
refer to urology
How many stones need surgery?
10-20%
Your patient has a urologic infection+stone
URGENT refer to urology
Your patient has AKI+stone
URGENT refer to urology
