Kidney Pharm

Question 1

What are the mechanisms of reabsorption in the PCT?

Answer 1

NaHCO3, NaCl, glucose, amino acids, and other organic solutes are reabsorbed via transport systems.
K+ follows it’s gradient in the paracellular pathway
NaHCO3 and NaCl are most relevent toward diuretic action

Question 2

Which diuretic group works primarily in the PCT?

Answer 2

CA inhibitors

Block the reabsorption of HCO3

Question 3

Where are organic acid secretory systems located?

Answer 3

The meddle part of the straight part of the proximal tubule.

Question 4

What is the function of the thick ascending limb “loop diurectics”?

Answer 4

They block the Na2ClK symporter that reabsorbs only solute and dilutes the luminal fluid. When K+ is reabsorbed it creates a high concentration in the cell resulting in back leak into the lumen. This increases the + ion concentration and provides a gradient for the paracellular reabsorption of Mg2+ and Ca2+.

Question 5

What loss of ions does loop diuretic cause?

Answer 5

K+, Na+, Mg2+, Ca2+, Cl-

Question 6

What diuretics affect the DCT?

Answer 6

Thiazide diuretics block the NCC symporter responsible for reabsorption of Na and Cl-.

Question 7

Do thiazide diuretics affect Ca2+ reabsorption?

Answer 7

No, Ca2+ in the DCT is accomplished via a channel that is sensitive to the gradient created by the Ca2+/Na+ exchanger on the interstitial side. This is stimulated by PTH

Question 8

What is the site where all adjustments to K+ is regulated?

Answer 8

The collecting tubule system

Question 9

What is the function of the principal cells of the distal tubule?

Answer 9

They are the major site of Na+, K+, and H20 transport

Question 10

What is the function of the intercalated cells of the distal tubule?

Answer 10

H+, and HCO3 secretion

Question 11

How does transport in the principal cells work?

Answer 11

Na+ and K+ have seperate channels on luminal membrane
More Na+ enters than K+ is secreted creating 50-70mV negative change in lumen
Negative charge drives paracellular Cl- reabsorption and draws K+ out of the cell

Question 12

Through what mechanism does aldosterone act?

Answer 12

It increases luminal expression of ENaC and increases action of Na+/K+ transporters,
Through gene transcription it causes an increase in transepithelial negative potential resulting in more Na+ uptake and more K+ excretion.

Question 13

What cells does ADH affect?

Answer 13

Principal cells to increase expression of AQP2 and UT1 (in the medulla)

Question 14

What is the effect of prostaglandins in the kidney?

Answer 14

They block the reabsorption of Na+ and the TAL and block the reabsorption of water at the CD.
Blockade of prostaglandins with NSAIDS can decrease the efficacy of loop diuretics because of the necessary aciton of PGE2

Question 15

What are the uses of CA inhibitor diuretics?

Answer 15

Glaucoma (decreased fluid formation)
Unrinary Alkalization (To prevent stone formation in cystinuria)
Metabolic Alkalosis
Acute Mountain Sickness (to excrete excess bicarb)

Question 16

What are the toxicities of CA inhibitors?

Answer 16

Hyperchloremic Metabolic Acidosis (until stopped)
Renal Calculi (Ca2+ insoluble in alkalotic urine)
Renal K+ wasting
Drowsiness
Parasthesias

Question 17

When are CAs contraindicated?

Answer 17

Cirrhosis

Question 18

What are clinically important indications for loop diuretics?

Answer 18

Acute pulmonary edema
Acute hypercalcemia (give with saline)
Hyperkalemia
Acute Renal Failure
Anion Overdose

Question 19

What are the toxicities of loop diuretics?

Answer 19

Hypokalemic Metabolic Acidosis (increased Na in CD)
Ototoxicity
Hyperuricemia (hypovolemia enhances Uric Acid reab)
Hypomagnesemia (no electrical gap to drive reab)

Question 20

What are the major clinical indications for thiazide diuretics?

Answer 20

Hypertension
Heart failure
nephrolithiasis due to hypercalciuria
Nephrogenic diabetes insipidus

Question 21

What are the toxicities of thiazide diuretics?

Answer 21

Hypokalemic metabolic acidosis
Impaired carbohydrate tolerance
Hyperlipidemia
Hyponatremia
Allergic reactions

Question 22

How do spironolactone and eplerenone cause diuresis?

Answer 22

Blocking the effects of aldosteron via competitive inhibition

Question 23

How does amilioride exhibit its effect?

Answer 23

Blocking ENaC

Question 24

What are the toxicities of K+ sparing diuretics?

Answer 24

Hyperkalemia
Hyperchloremic Metabolic Acidosis
Gynecomastia
Acute Renal Failure
Kidney Stones

Question 25

What diuretics are useful in patients with renal failure and kidney disease?

Answer 25

Loop diuretics, or a combination of loop diuretics and thiazides

Question 26

What diuretics are useful in patients with cirrhosis?

Answer 26

K+ sparing diuretics because they block the aldosterone which may be in excess during cirrhosis. Used in conjunction with loop diuretics

Question 27

What should be used for idiopathic edema?

Answer 27

Spirnolactone, low salt diet, or compression stockings

Question 28

What should be used in essential hypertension?

Answer 28

HCTZ

Question 29

What diuretics should be used in patients with nephrolithiasis?

Answer 29

Thiazides, with increased fluids and decreased sodium diet

Question 30

What should be used in hypercalcemia?

Answer 30

Loop diuretics in combination with saline

Question 31

What should be used in Diabetes insipidus?

Answer 31

Thiazide diuretics