Nephrolithiasis Flashcards
What is the most important factor to correct with kidney stones?
low urinary flow
What might explain the higher incidence of kidney stones in men?
Women typically excrete more citrate and less calcium than men
Why is the southeastern United States considered the Stonebelt?
Wide consumption of iced tea. Tea is loaded with calcium oxalate.
How might excess dietary sodium contribute to kidney stones?
leads to excessive Ca and uric acid urine secretion
How might renal tubular acidosis contribute to kidney stones?
decreased Ca reabsorption
How might excess dieatary meat contribute to kidney stones?
uric acid overproduction
What is the most common stone composition?
Calcium oxalate 80%
What conditions are calcium phosphate stones associated with?
renal tubular acidosis & Primary Parathyroidism
What do calcium phosphate crystals look like under microscope?
long crystalline rods
What do uric acid crystals look like under microscope?
irregular-shaped crystals
Clinical presentation of stones
pain, hematuria, N/V, dysuria, urgency
Most common places a stone will cause obstruction
Ureter at the abdominal crease and ureterovesicular junction
Characterization of pain associated with kidney stone
severe intermittent colicky flank pain. Localized to the CVA
Characterization of pain associated with ureteral stone
sharp, acute, spasm-like flank pain. Movement down will radiate pain to umbilical region, then to groin
Gold standard for diagnosing nephrolithiasis
Non-contrasted helical CT scan
What is the imaging test of choice during pregnancy for a suspected stone?
ultrasound.
What labs do you need to check before prescribing Toradol or other NSAID?
BMP to check Cr
If a stone is <5mm what percent pass spontaneously?
90%
For a stone 5-10mm what can increase the chance of passage?
alpha & calcium channel blockers (dilate ureters so stone can pass)
Name 4 alpha 1 blockers
doxazosin (Cardura), prazosin (Minipress), Terazosin, Tamsulosin (Flomax)
Most important factor for acute treatmant and to prevent stone recurrence
increase urine output to 2 L/day by increased fluids
Relapse rate in the first 5-10 yrs after first episode
50%
treatment for hypercalciuria calcium oxalate stones
thiazide diuretics, decreased Na intake
treatment for hyperoxaluria stones
decrease oxalate intake, increase Ca intake (binds enteric oxalate)
treatment for hypocitraturia stones
potassium citrate
treatment for uric acid stones
allopurinol and potassium citrate
how does citrate prevent stones?
inhibits calcium salt formation
What is the composition of struvite stones?
magnesium, ammonium, and calcium phosphate
What is the most common UTI urea-splitting organism that can contribute to struvite stones?
proteus
What causes cystine stones?
Autosomal recessive disorder leading to decreased cystine resorption in the kidney- acidic urine
treatment for cystine stones
Hydration, urine alkalization, Low Na/protein diet cystine binders
What drugs promote calcium stone formation?
loops, antacids, glucocorticoids, theophylline, Vitamins D & C
What drugs precipitate into stones?
acyclovir, indinavir, triamterene
Most common surgical treatment for stones
shock wave lithotripsy
