Nephrolithiasis Flashcards
What percentage of men and what percentage of women will have a kidney stone by age 70?
12% of men
5% of women
80% of stones are made of what?
calcium
Of the calcium stones, are there more calcium oxalate or more calcium phosphate stones?
more oxalate
What are the three less common kinds of stones?
uric acid
struvite
cystine
What is the most helpful imaging study for KS? Others?
CT scan is the most common, but we use US for repeaters and KUB can be helpful on occasion
KUB are only really good for what kind of stone?
calcium stones - they’re the only ones that would be radiopque on xray (cystine maybe, but less likely)
How do you treat a kidney stone acutely?
pain meds, hydration, alpha blocker or ca channel blocker
What are the different means you can use to get a stone out?
ureteroscopy extracorporeal shock wave lithotropsy endoscopic lithotripsy pyelolithotomy percutaneous nephrolithotomy
What will calcium oxalate crystals look like?
both dumbbell-shaped and envelope-shaped
some also have a needle-shaped appearance
What are the risk factors for calcium stone formation?
- increased calcium excretion
- increased uric acid excretion
- reduced citrate excretion
- low urine volume
- increased oxalate excretion
What are three things that can cause idiopathic hypercalciuria contributing to kidney stone formation?
- absorptive hypercalciuria (autosomal dominant elevated active vitamin D levels)
- Fasting (resorptive) hypercalciuria - bone loss
- Renal hypercalciuria - renal leak with abnormal calcium reabsorption in the proximal tubule
What are some things that can cause low citrate contributing to Ca kidney stones?
- chornic diarrhea
- renal tubular acidosis
- ureteral diversion
- high protein diet
- topiramate
Basically anything that gives metabolic acidosis!!!
What are some ways you can get hyperoxaluria contributing to Ca kidney stones?
- high oxalate diet
- increased oxalate absorption from a low calcium diet , absorptive hypercalciuria, enteric hyperoxaluria
- overproduction of oxalate (primary hyperoxaluri
What are some medical conditions associated with caclium stone formation>
primary hyperparathyroidism - too much Ca resorption from bone
medullary sponge kidney (reflux of urine back into the renal papilla of the kidney)
distal renal tubular acidosis
What should you do in a metabolic workup of a calcium stone?
- measure plasma calcium
- measure parathyroid hormone
- measure electrolytes
- check serum uric acid
- 24 hr urine collection for volume, calcium, uric acid, citrate, osalate, creatinine, pH, sodium, and phosphorus