Nphro: Nphrolth Flashcards
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
Risk of stoone disease is highest in
a. middle-aged white men
b. middle-aged black men
c. women of reproductive age
d. menopausal women
A
Effect of weight gain on risk of stone formation
increase
True about urinary risk factors for stone formation EXCEPT
a. hypercalciuria increases likelihood of calcium phosphate and calcium oxalate stones
b. there is no widely accepted cutoff that distinguishes between normal and abnormal urine calcium excretion
c. Levels of urine excretion is higher in individuals with a history of nephrolithiasis
d. Primary renal calcium loss is a common cause of hypercalciuria
D; rare
Effect of higher urine oxalate excretion on calcium stone formation
increase
Effect of higher dietary calcium intake on oxalate
decrease GI oxalate absorption
True about urine Citrate
a. natural inhibitor of calcium-containing stones.
b. higher urine citrate excretion increases the risk for calcium oxalate stones
c. Citrate reabsorption is influenced by intracellular pH of distal tubular cells
d. Metabolic alkalosis will lead to a reduction in citrate excretion
A.
lower urine citrate excretion increases risk for claclium oxalate stone
citrate reabsorption is influenced by intracellular pH of proximal tubular cells
metabolic acidosis will lead to a reduction citrate excretion
True about urine uric acid
a. higher urine levels of uric acid is a risk factor for uric acid stone formation
b. excess purine consumption increase uric acid stone formation
c. urine uric acid does not appear to be associated with the risk of calcium oxalate stone formation
d. AOTA
e. NOTA
D
True about urine pH
a. Uric acid stones form when pH is >=5.5
b. Calcium phosphate stones are more likely to form when urine pH is <=6.5
c. Cystine is more soluble at lower urine pH
d. Calcium oxalate stones are not influenced by urine pH
D
Uric acid stones: <=5.5
Calcium phosphate stones: >=6.5
Cystine is more sooluble at higher urine pH
risk of nephrolithiasis is more than ___ greater in individuals with a family history of stone disease.
a. 1.5x
b. 2x
c. 2.5x
d. 3x
B
Two most common and well-characterized rare monogenic disorders that lead to stone formation are
primary hyperoxaluria
Cystinuria
Two common presentations for individuals with an acute stone event
renal colic
painless gross hematuria
True about clinical manifestation of nephrolithiasis
a. renal colic does not subside completely and may vary in intensity
b. when a stone moves into the ureter, discomfort often begins with sudden onset unilateral flank pain.
c. Intensity of pan can increase rapidly and there are no alleviating factors
d. pain is not accompanied by nausea/vomiting
All Except D
pain in the ipsilateral labium, where is the stone?
distal ureter