Nephrolithiasis Flashcards
ureteral colic may mimic any intra-abdominal process.what would make you this diagnosis
if the paatient has abdominal pain with hematuria. hematuria is a big clue in the presence of stones
what are some important terms when discussing nephrolithiasis?
- interplay of concentration (calcium oxalate, uric acid, and other solutes)
- degree of supersaturation
patients with recurrent kidney stones have low numbers of what
citrate which is an inhibitor of stones
which medication has a mechanism to reduce uric acid can produce xanthine stones?
allopurinol
an antiseizure medication but can cause proximal RTA and possibly kidney stones
topirimate
what are the most common form or types of kidney stones
calcium oxalate or calcium phosphate
cystine
uric acid
struvite
which types of stones are always associated with urinary tract infections?
struvite
stones due to UTIs especially with urea splitting organisms that produce urease and produce a special kind of stone
if the stones are Ca phosphates then you should think
of primary hyperparathyroidism or distal RTA (renal tubular acidosis)
What measurements in urine chemistry do you need to be aware of?
- Na
- Volume
- Ca
- Uric Acid
- Oxalate
- Citrate
- Cystine
- pH
- Creatinine
which levels that are high will increase the risk factors for calcium oxalate?
-calcium, oxalate, uric acid
which levels if low will increase the risk factors for calcium oxalate
citrate, volume, dietary calcium, potassium, phytate
what will increase the risk factor for calcium oxalate when the dietary levels are increased?
purines, animal protein, sodium, sucrose, calcium-supplemental, vitamin C fluid(interferes with oxalate catabolism)
what are the major risk factors for calcium stones?
- hypercalciuria
- hypocitraturia
- hyperuricosuria
- hyperoxaluria
- low urine volume
- infection with urea splitting organisms-proteus
- medullary sponge kidney
what is medullary sponge kidney
genetic disease that has calcifications in the renal medulla that causes stone formation
patient comes in with substance abuse, works in garage, gets seizures, renal failure, met acidosis, he has tons of these in his urine what is the pathogenesis of his disorder
he has ethylene glycol which interferes with oxalate metabolism and he gets Ca oxalate stones
what are the two causes of hypercalciuria
- increased filter load
- decreased absorption which parallels Na in PCT
hypercalciuria may be
idiopathic (increased vit d and decreased bone mineral density, especially in women) or secondary to Primary hyperparthyroidsm, RTA, Sarcoidosis, immobilization, pagets disease, hyperthyroidism, vitamin D intoxication, granulomatous disease, Multiple myeloma
what are the dietary treatments of hypercalciuria?
- high fluid intake reduces the supersat index
- restrict dietary sodium
- but do not restrict dietary Ca becuase it will result in more oxalate stones and too high will result in Ca stones
- restrict protein from other animals because they increase urinary acidity
what is the mechanism of thiazide diuretics
reduce urinary calcium by (mild) reducing the volume increasing both Na and Ca reabsorption
potassium citrate do what
they decrease and inhibit the formation of Ca stone formers
potassium is preferred to Na and citrate is preferred to HCO3
lemon juice is preffered to what and why
orange (oxalate)
what two things reduce citrate
acidosis and hypokalemia
what two GI problems can cause stones?
Intestinal oxaluria (malabsorption of bile or fatty acids seen in IBD or short bowel you get increased urinary excretion of oxalate
treatment of hyperoxaluria?
- avoid high oxalate foods
- such as tea coffee, nuts, chocolate, green leafy vegetables, collard greens, wheat barn,
- have a low fat diet
