Can someone explain this to me?

[superoxide]

This question is from Qbook:

A patient with essential hypertension is starting diuretic therapy. he has a history of calcium oxalate renal stones. which of the following diuretics would be most appropriate for this patient?
a) acetazolamide
b) furosemide
c) hydrochlorothiazide
d) Spiranolactone
e) Triamterene

According to Qbook, the answer is (c).

Dont thiazide diuretics DECREASE Ca excretion and therefore CONTRAINDICATED in this patient (because of his history of calcium stones)? I chose Furosemide (because it INCREASES Ca excretion)

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[Dr. Ram-Rod]

The stone forms because you are excreting Ca++.. meaning more Ca++ makes it out to the ureter for the stone to form. If you are excreting less Ca++ (less is getting out to the ureters) you have a lower chance of a stone forming.
I believe Goljan (or ERF) mentioned that this is likely just due to the diurectic pushing more fluid through the system so there is less likelihood that a stone has the chance to form.

This question is from Qbook:

A patient with essential hypertension is starting diuretic therapy. he has a history of calcium oxalate renal stones. which of the following diuretics would be most appropriate for this patient?
a) acetazolamide
b) furosemide
c) hydrochlorothiazide
d) Spiranolactone
e) Triamterene

According to Qbook, the answer is (c).

Dont thiazide diuretics DECREASE Ca excretion and therefore CONTRAINDICATED in this patient (because of his history of calcium stones)? I chose Furosemide (because it INCREASES Ca excretion)

 

[PsychoDan]

This question is from Qbook:

A patient with essential hypertension is starting diuretic therapy. he has a history of calcium oxalate renal stones. which of the following diuretics would be most appropriate for this patient?
a) acetazolamide
b) furosemide
c) hydrochlorothiazide
d) Spiranolactone
e) Triamterene

According to Qbook, the answer is (c).

Dont thiazide diuretics DECREASE Ca excretion and therefore CONTRAINDICATED in this patient (because of his history of calcium stones)? I chose Furosemide (because it INCREASES Ca excretion)

From what I understand, decreasing Ca excretion is exactly what you want in someone with susceptibility to Ca stones. I suppose Ca stones form in an area after the reabsorption of Ca from hydrochlorothiazide, thus less is there to form if you are hyper-reabsorbing it in the distal convoluted tubule. Goljan talks about this very thing.

Hydrochlorothiazide will increase Ca in the serum, which does seem a bit counterintuitive.

Anyone disagree?

 

[Mye Eye]

From what I understand, decreasing Ca excretion is exactly what you want in someone with susceptibility to Ca stones. I suppose Ca stones form in an area after the reabsorption of Ca from hydrochlorothiazide, thus less is there to form if you are hyper-reabsorbing it in the distal convoluted tubule. Goljan talks about this very thing.

Hydrochlorothiazide will increase Ca in the serum, which does seem a bit counterintuitive.

Anyone disagree?

this does seem counterintuitive, but you have to remember...the MAJORITY of calcium stones form in a EUcalcemic person with hypercalciURIA...so if there is less calcium in the urine, it will help to decrease the calcium stone formation

 

[superoxide]

this does seem counterintuitive, but you have to remember...the MAJORITY of calcium stones form in a EUcalcemic person with hypercalciURIA...so if there is less calcium in the urine, it will help to decrease the calcium stone formation

So, if you are taking hydrochlorothiaizide, you are losing less calcium (there is less calcium in ureter for stones to form). but then you end up with hypercalcemia. Doesn't hypercalcemia lead to hypercalciuria and stones and therefore a thiazide diuretic would still be contraindicated in this patient? So, technically hydrochlorothiazide is not a correct answer either.

Even more confused

 

[(nicedream)]

So, if you are taking hydrochlorothiaizide, you are losing less calcium (there is less calcium in ureter for stones to form). but then you end up with hypercalcemia. Doesn't hypercalcemia lead to hypercalciuria and stones and therefore a thiazide diuretic would still be contraindicated in this patient? So, technically hydrochlorothiazide is not a correct answer either.

Even more confused

Hypercalcemia leads to hypercalciuria except in the setting of HCTZ use, in which case there would just be plain hypercalcemia without elevated Ca in the urine since HCTZ causes retention of it.

 

[superoxide]

THANK YOU EVERYONE