Nphro: Nphrolth Flashcards
(94 cards)
Arrange the following from most common to leat
a. Calcium phosphate
b. Calcium Oxalate
c. Cystine
d. Uric acid
e. Calcium carbonate
f. Struvite
B. Calcium Oxalate A. Calcium Phosphate D. Uric Acid F. Struvite C. Cystine
E - not included
3 medications associated with stone formation
ATA
acyclovir, triamterene, atazanavir,
Conditions that predispose to stone formation (4)
Dā POGi
DM type 2 DRTA Primary hyperparathyroidism Obesity Gastrointestinal malabsorption
Medical conditions likely to be present in individuals with a history of nephrolithiasis
HGRC3 Hypertension Gout Reduced bone mineral density Cardiovascular disease Cholelithiasis Chronic kidney disease
True about nephrolithiasis
a. nephrolithiasis does not directly cause UTI
b. UTI in the setting of an obstructing stone is a medical emergency
c. both
d. neither
C
This is the point at which the concentration product exceeds the solubility product.
Supersaturation
Even though the urine in most individuals is supersaturated with respect to one or more types of crystals, why is it that people do not continuously form stones?
the presence of inhibitors of crystallization prevents the majority of the population from continuously forming stones
Most clinically important inhibitor of calcium-containing stones is
urine citrate
T/F calculated supersaturation predict stone formation
F; it does not perfectly predict stone formation
calcium oxalate stones grow on calcium phosphate at the tip of the renal papilla. This is called
Randallās Plaque
3 categories of risk factors for nephrolithiasis
DUN
dietary
urinary
non-deietary
Dietary factors that are associated with increased risk of nephrolithiasis include
FOSSA fructose oxalate sodium sucrose animal protein
Dietary factors associated with lower risk of stone formation
CPP
calcium
potassium
phytate
True about effect of dietary calcium in stone formation
a. Higher dietary calcium intake is related to a lower risk of stone formation
b. Low calcium intake is advised for stone formers
c. Supplemental calcium lower the risk for stone formation
d. NOTA
A
High dietary but not supplemental calcium lower the risk of stone formation.
What is the reason behind risk reduction with higher calcium intake?
reduction in intestinal absorption of dietary oxalate that results in lower urine oxalate
Why is low calcium intake contraindicated in stone formers (2) ?
Increases the risk of stone formation and may contribute to lower bone density
Urinary oxalate is derived from
a. endogenous production
b. absorption of dietary oxalate
c. both
d. neither
C
Strong risk factor for stone formation
a. dietary oxalate
b. urinary oxalate
c. both
d. neither
B; dietary oxalate is only a weak risk factor for stone formation
Higher dietary intake of animal protein may lead to
a. increased excretion of calcium and uric acid
b. Decreased urinary excretion of citrate
c. both
d. neither
C
True about diet and stone formation EXCEPT
a. animal protein increase risk of stone formation
b. higher sodium and sucrose intake increases calcium excretion dependent of calcium intake
c. potassium-rich foods increase urinary citrate excretion due to their alkali content.
d. Magnesium and phytate decrease risk for stone formation
B; independent of calcium intake
The following increase risk for stone formation EXCEPT
a. Vitamin C supplements
b. Vitamin B6
c. sugary-sweetened beverage
d. coffee
D; although supplemental vit B6 may be beneficial in selected patients with type 1 primary hyperoxaluria, the risk is not reduced in other patients, therefore D. Coffee is the best answer.
The risk of stone formation ______ as urine volume decreases
a. increase
b. decrease
A
urine output which more than doubles the risk of stone formation
<1L/d
What is the main determinant of urine volume
Fluid intake