Renal lecture 6 dieuretics in kidney disease

Question 1

What is low H+ (high pH) called?
What is high H+ concentarion (Low pH) called?

Answer 1

Low H+ concentration (high pH): alkalosis
-High H+ concentration (low pH): acidosis

Question 2

What aare the 2 forms of alkalosis and acidosis?

Answer 2

Respiratory alkalosis (results from altered respiration)
Metabolic alkalosis (results from other causes)
Respiratory acidosis (results from altered respiration)
Metabolic acidosis (results from other causes)

Question 3

What are the first 2 response options to acidosis?
What is secreted in each?
What does this contribute to?

Answer 3

1. Sufficient H+ are secreted to reabsorb all the filtered HCO3
2. Still more H+are secreted and this contributes new HCO3- to the plasma as these H+ are excreted bound to non-HCO3-buffer such as HPO42-

Question 4

What type of excretion is enhanced in the 3rd reason for renal response to acidosis?
What is the net result from the renal response to acidosis, what is added more than usual?

Answer 4

3. Tubular glutamine metabolism and ammonium excretion are enhanced, which also contributes new HCO3- to the plasma.
   -More new HCO3- than usual are added to the plasma, thereby compensating for the acidosis. The urine is highly acidic (lowest attainable pH = 4.4)

Question 5

What are the first 2 responses to alkalosis?
What is excreted into the urine, what has a small excretion?

Answer 5

1. Rate of H+ secretion is inadequate to reabsorb all the filtered HCO3-, so the significant amounts of HCO3- are excreted in the
   urine.
2. There is little or no H+ secretion on non-HCO3- urinary buffers.

Question 6

What happens to glutamine metabolism and ammonium excretion in reponse to alkalosis?
What is the net result of the alkalosis response?

Answer 6

-Tubular glutamine metabolism and ammonium excretion are
decreased, so that little or no new HCO3- is contributed to the plasma from this source.
-Net result: Plasma HCO3-will decrease, thereby compensating for the alkalosis. The urine is highly alkaline (pH > 7.4)

Question 7

What are the classifications for respiratory alkalosis and respiratory acidosis?
What is increase/decreasing?
What is the cause of CO2, and HCO3- change

Answer 7

resp. acidosis= increase in H+, increase in HCO3-, and increase in CO2
-respiratory alkalosis=decrease in H+, decrease in HCO3-, and decrease in CO2
-HCO3- change is caused by renal compensation
-CO2 chnage is caused by primary abnormality

Question 8

What are the classifications for metabolic alkalosis and metabolic acidosis?
What is increase/decreasing?
What is the cause of CO2, and HCO3- change?
What is metabolic driven by?

Answer 8

met. acidosis= increase in H+, decrease in HCO3-, and decrease in CO2
-met. alkalosis=decrease in H+, increase in HCO3-, and increase in CO2
-cause of HC3O- change is primary abnormality
-cause of CO2 change is ventilatory compensation
-change in HC3O- is the primary change

Question 9

How do you classify acidosis vs alkalosis?
Respiratory vs metabolic

Answer 9

-resp. acidosis= increase in H+, increase in HCO3-, and increase in CO2
-respiratory alkalosis=decrease in H+, decrease in HCO3-, and decrease in CO2
met acidosis=increase in H+, decresae in HCO3- and PCO2
met alkalosis=decrease in H+ and increase in HCO3- and PCO2

Question 10

What are clinical example of resp acidosis and alkalosis?

Answer 10

-Respiratory acidosis: respiratory failure with CO2 retention (ex. ephysema)
-Respiratory alkalosis: hyperventilation (e.g. high altitude, also due to panicking)

Question 11

What are clinical examples of metabolic acidosis and alkalosis

Answer 11

-Metabolic acidosis: diarrhea (loss of HCO3- in diarrhea), renal failure (accumulation of inorganic acids)
-Metabolic alkalosis: vomiting (loss of H+in vomits), hyperaldosteronism (increased H+secretion in DCT and CCD

Question 12

What are diruetics used for?
What do diuretics act on?
What exretion increases?

Answer 12

Drugs used clinically to increase the volume of urine excreted are known as diuretics.
Diuretics act on the tubules to inhibit the reabsorption of sodium, along with chloride and/or bicarbonate, resulting in increased excretion of these ions.
-Water excretion increases, too (loss of Na+ and water)

Question 13

Where do loop diuretics act on?
what do they inhibit?
What is an example of loop diuretic?

Answer 13

-Acts on the thick ascending limb of the loop of Henle.
* Inhibits cotransport of sodium, chloride and potassium (Na+ K+-2Cl- cotransporter).
* One of the commonly used diuretics.
* e.g. furosemide

Question 14

Where does most of the Na reabsorption occur?

Answer 14

67% in the proximal tubules

Question 15

What do potassium sparing diuretics inhibit?
What happens to plasma concentration?
What is its effect on aldosterone?
What are 2 examples?

Answer 15

Inhibit sodium reabsorption in the CCD, and also inhibits potassium secretion there.
-Thus, unlike the other diuretics, plasma concentration of potassium does not decrease
-Either block the action of aldosterone or block the (aldosterone-regulated) epithelial sodium channel in the CCD.
* e.g. amiloride, spironolactone

Question 16

What do sparing diruetics block?
What does the sparing diuretic amiloride block?

Answer 16

-aldosterone
-amiloride blocks Na+ reabsorption

Question 17

What are some clinical uses for diuretics, why would we use them?
Whats an example of a health issue in when we would use diuretic?

Answer 17

Renal retention of salt and water: abnormal expansion of the extracellular fluid (edema)
Example 1: congestive heart failure (cardiac failure leading to lower cardiac output)
-circulating volume is low so the kidney does not have enough volume, kidney retains fluid, and water accumulates in lungs

Question 18

Why would we use diuretics for hypertension?

Answer 18

In some patients with hypertension, renal retention of salt and water contribute to high blood pressure

Question 19

What are some 6 of the common features of kidney disease/failure?

Answer 19

-Proteinuria (protein in the urine)
-Accumulation of waste products in the blood (urea, creatinine, phosphate, sulfate)
-High potassium concentration in the blood
-Metabolic acidosis
-Anemia (decreased secretion of erythropoietin)
-Decreased secretion of 1,25-(OH)2 vitamin D(leading to hypocalcemia)

Question 20

When would we need renal replacement therapy?
What are the 3 renal replacement therapies?

Answer 20

-when more than 90% of nephrons stop working
-Renal replacement therapy:
1. Hemodialysis
2. Peritoneal dialysis
3. Kidney transplantation

Question 21

How oftenn would you do hemodialysis?

Answer 21

at least 3 times per week

Question 22

What is the setup for the hemodialysis machine?

Answer 22

Question 23

What is peritoneal dialysis?
Where is fluid injected?

Answer 23

The lining of the patient’s own abdominal cavity (peritoneum) is used as a dialysis membrane.
-Fluid is injected into the cavity via a tube inserted through the abdominal wall

Question 24

Where do solutes diffuse into during peritoneal dialysis?
How often is fluid exchanged?

Answer 24

Solutes diffuse into the fluid from the person’s blood.
Fluid is exchanged several time per day

Question 25

Where do we get kidney transplants from?
What treatmen has improved over the years?
What is the current issue?

Answer 25

-Either from recently deceased persons (cadaveric transplant) or from a living related/unrelated donor.
-Anti-rejection treatments have improved dramatically in recent years. Organ shortage is a problem.