Posts: 3,675,934
Threads: 734,342
Joined:
Sep 2021
Reputation:
5
A 40 year old Caucasian woman with stage 1 hypertension would like to start diuretic therapy. Her physician notes that the woman has a history of nephrolithiasis. A past urinalysis revealed numerous tetrahedron shaped crystals. What diuretic is most appropriate considering this woman’s past medical history?
A - Furosemide
B - Spironolactone
C - Mannitol
D - Captopril
E - Hydrochlorothiazide
Posts: 3,675,934
Threads: 734,342
Joined:
Sep 2021
Reputation:
5
are these calcium oxalate crystals?
Posts: 3,675,934
Threads: 734,342
Joined:
Sep 2021
Reputation:
5
E.....it is right
The most common type of kidney stone is composed of calcium oxalate crystals, occurring in about 80% of cases. The figure in this question reveals tetrahedron shaped crystals which are pathonomonic for calcium oxalate crystals. To prevent precipitation of calcium oxalate and recurrence of kidney stones, a diuretic should be used that reduces calcium excretion in the renal tubules. Hydrochlorothiazide is one such diuretic, which blocks the Na/Cl co transporter in the distal convoluted tubule and also increases calcium reabsorption . It is also a the first line treatment in hypertension in non diabetic patients.
A – Furosemide is a loop diuretics that acts by inhibiting the Na-K-2Cl symporter in the thick ascending limb of the loop of Henle. It also increases calcium excretion and would increase this woman’s likelihood of developing calcium oxalate stones.
B - Spironolactone is a K+ sparing diuretic that inhibits the effect of aldosterone by competing for intracellular aldosterone receptors in the collecting duct. It also increases the excretion of calcium and would increase this woman’s likelihood of developing calcium oxalate stones.
C – Mannitol is an osmotic diuretic that is filtered by the glomerulus of the kidney, but is incapable of being resorbed from the renal tubule, resulting in decreased water and Na+ reabsorption via its osmotic effect. Consequently, mannitol increases water and Na+ excretion, thereby decreasing extracellular fluid volume. Mannitol is not first or second line in controlling a hypertension.
D – Captopril is an ACE inhibitor that blocks the conversion of angiotensin I to angiotensin II and thus interrupts the Renin-Angiotensin-Aldosterone axis. Ace inhibitors are first line in diabetics with hypertension.
