Diets and Kidney Function in Medicine

Questions and Answers

What are the two major implications of diets?

They treat obesity and are used to reduce cholesterol

They treat asthma and are used to reduce inflammation

They treat diabetes and are used to mobilize fluid

They treat hypertension and are used to mobilize fluid (correct)

What is the basic functional unit of the kidney?

Glomerulus

Distal convoluted tubule

Proximal convoluted tubule

Nephrons (correct)

What is the primary function of the glomerulus?

Filtration of small molecules (correct)

Reabsorption of sodium and chloride

Maintenance of acid-base balance

Active secretion of metabolic waste

What is the purpose of the Loop of Henle?

Regulation of extracellular fluid volume Signup and view all the answers

What are the three basic functions of the kidney?

Cleansing extracellular fluid, maintaining acid-base, and excreting metabolic waste Signup and view all the answers

What is the process by which the kidney excretes metabolic waste?

Active secretion Signup and view all the answers

What type of molecules do not undergo filtration in the glomerulus?

Lipids and proteins Signup and view all the answers

What is the main mechanism of action of diuretics?

Blocking sodium and chloride reabsorption Signup and view all the answers

What is the purpose of the transport compounds in the kidney?

To help with secretion Signup and view all the answers

Where do Loop diuretics work in the nephron?

Loop of Henle Signup and view all the answers

What is the prototype drug of the Lute diuretics?

Lasix Signup and view all the answers

What percentage of sodium chloride is filtered in the Loop of Henle?

20% Signup and view all the answers

What is the therapeutic goal of using Lasix?

Decrease edema Signup and view all the answers

What is the duration of action of Lasix?

8 hours Signup and view all the answers

Why should you be cautious when using Lasix in patients with cardiovascular disease?

It can worsen cardiovascular disease Signup and view all the answers

What is an example of an osmotic diuretic?

Mannitol Signup and view all the answers

Why should Lasix be avoided in pregnant women?

It can cause maternal death, abortion, and fetal resorption Signup and view all the answers

What is the Beers criteria related to?

Potentially inappropriate medication in elderly patients Signup and view all the answers

What is the effect of the potassium sparing diuretic on sodium reabsorption?

Decreased sodium reabsorption Signup and view all the answers

What is the primary therapeutic goal of using the potassium sparing diuretic?

To counteract potassium wasting effects Signup and view all the answers

Why is the potassium sparing diuretic contraindicated in elevated potassium levels?

It increases potassium levels Signup and view all the answers

What is a common adverse effect of the potassium sparing diuretic?

Muscle cramps Signup and view all the answers

What is the reason for monitoring potassium levels when using the potassium sparing diuretic?

To prevent hyperkalemia Signup and view all the answers

What is the duration of action of the potassium sparing diuretic?

It starts working within a few hours Signup and view all the answers

What is the advantage of Las diuretics in patient populations with renal impairment?

They can produce diuresis even with a lack of renal blood flow Signup and view all the answers

What is the equivalent dose of Vmax to 40 mg of Las?

1 mg Signup and view all the answers

What is a potential adverse effect of Las diuretics?

Hypertonia Signup and view all the answers

What is the interaction between Las diuretics and potassium-sparing diuretics?

They have an antagonistic effect Signup and view all the answers

What is the primary mechanism of action of thiazide diuretics?

Blocking reabsorption of sodium and chloride in the distal convoluted tubule Signup and view all the answers

What is a characteristic of thiazide diuretics compared to loop diuretics?

They are less potent in their diuretic effect Signup and view all the answers

What is the minimum glomerular filtration rate required for thiazide diuretics to be effective?

30 ml/min Signup and view all the answers

What is a potential adverse effect of thiazide diuretics on electrolyte levels?

Hypokalemia Signup and view all the answers

What is the effect of thiazide diuretics on uric acid levels?

They increase uric acid levels Signup and view all the answers

Why is it important to monitor patients' blood pressure when taking thiazide diuretics?

To prevent hypotension Signup and view all the answers

What is the time frame for diuresis to peak with Lex?

46 hours Signup and view all the answers

What is a common adverse effect of Lex and Loop Diuretics?

Photo sensitivity Signup and view all the answers

What is the purpose of teaching patients to do daily weights at home?

To identify signs of hypokalemia Signup and view all the answers

What is the mechanism of action of Spironolactone?

Inhibition of aldosterone Signup and view all the answers

What is the primary use of Potassium-sparing Diuretics?

To counteract potassium loss Signup and view all the answers

What is a unique feature of Spironolactone's dosing and administration?

Delayed effects for 48 hours Signup and view all the answers

What is a potential interaction between Spironolactone and other medications?

Reduced effect with potassium supplements Signup and view all the answers

What is the black box warning associated with Spironolactone?

Risk of tumors in rats Signup and view all the answers

What is the primary difference between Spironolactone and Tramiprosate?

Mechanism of action Signup and view all the answers

What should patients be educated on when taking Spironolactone?

The need to restrict potassium-rich foods Signup and view all the answers

Study Notes

Diets and Their Implications

Diets have two major implications: treating hypertension and mobilizing fluid in patients with liver failure, kidney disease, or heart failure.
The kidney's basic functional unit is the nephron, which has four functionally distinct regions: glomerulus, proximal convoluted tubule, Loop of Henle, and distal convoluted tubule.
The kidney serves three basic functions: cleansing extracellular fluid, maintaining extracellular fluid volume, and excreting metabolic waste and foreign substances.

Filtration, Reabsorption, and Secretion

Filtration occurs at the glomerulus, where small molecules like electrolytes, amino acids, glucose, and drugs are filtered.
Larger molecules like lipids and proteins remain in the bloodstream.
Reabsorption and secretion occur in the proximal convoluted tubule and distal convoluted tubule, respectively.

Diuretics

Diuretics share a common mechanism of action: blocking sodium and chloride reabsorption, causing excretion and diuresis.
There are four main categories of diuretics:
- Loop diuretics (e.g., Furosemide, Torsemide, Bumetanide)
- Thiazide diuretics (e.g., Hydrochlorothiazide)
- Osmotic diuretics (e.g., Mannitol)
- Potassium-sparing diuretics (e.g., Spironolactone, Triamterene)

Loop Diuretics

Loop diuretics are the most effective and produce the most significant loss of fluid and electrolytes.
They work in the Loop of Henle, blocking sodium and chloride reabsorption.
Examples of loop diuretics:
- Furosemide (Lasix)
  - Used for rapid mobilization of fluid, hypertension, and edema
  - Acts in the G segment of the ascending limb of the Loop of Henle
  - Produces profound diuresis
  - Adverse effects: hypotension, hypokalemia, hyperglycemia, hyperuricemia, and increased LD and triglycerides

Thiazide Diuretics

Thiazide diuretics are less potent than loop diuretics and work in the early segment of the distal convoluted tubule.
They increase renal excretion of sodium, chloride, potassium, and water, and can elevate plasma levels of uric acid and glucose.
Examples of thiazide diuretics:
- Hydrochlorothiazide
  - Used for hypertension, edema, and congestive heart failure
  - Acts in the early segment of the distal convoluted tubule
  - Produces milder diuresis
  - Adverse effects: similar to loop diuretics, plus photo sensitivity and hyperuricemia

Potassium-Sparing Diuretics

Potassium-sparing diuretics work by blocking the action of aldosterone in the distal nephrons, resulting in retention of potassium and excretion of sodium.
Examples of potassium-sparing diuretics:
- Spironolactone (Aldactone)
  - Used for hypertension, edema, and congestive heart failure
  - Acts as an aldosterone antagonist
  - Counteracts potassium wasting effects of other diuretics
  - Adverse effects: hyperkalemia, nausea, vomiting, and blood dyscrasias
- Triamterene
  - Used for hypertension, edema, and congestive heart failure
  - Acts by direct inhibition of sodium-potassium exchange
  - Counteracts potassium wasting effects of other diuretics
  - Adverse effects: hyperkalemia, nausea, vomiting, and blood dyscrasias

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Description

This lecture covers the importance of diets in treating hypertension and fluid mobilization in patients with liver, kidney, or heart failure. It also reviews kidney anatomy, pathology, and pharmacology.