Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Semester 3-Urinary > Lecture 10-Diuretics > Flashcards

Lecture 10-Diuretics Flashcards

1
Q

What is a diuretic?

A

A substance that promotes increased urine by kidney by increasing renal excretion of water and Na+ -> decreased ECF volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the broad ways in which diuretics work?

A
  • direct action on cells to block Na+ absorption
  • antagonising action of aldosterone
  • modification of filtrate content (osmotic diuretics)
  • inhibiting activity of carbonic anydrase enzyme in PCT to interfere with Na+ and HCO3- reabsorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do loop diuretics do?

A

Block apical NKCC2 in thick ascending limb of loop of Henle so less water reabsorbed later on -> Na+ and water loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What helps to drive absorption of Ca2+ and Mg2+?

A

K+ channels on apical membrane bring K+ in and creates positive lumen potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give examples of loop diuretics

A

Furosemide

Bumetanide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When are loop diuretics used?

A
  • Heart failure for treatment of symptoms (breathlessness and oedema)
  • nephrotic syndrome
  • renal failure
  • liver cirrhosis (spironolactone preferred)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How can loop diuretics be used to treat hypercalcaemia?

A

Impairs Ca2+ absorption in loop of Henle and increases urinary excretion of Ca2+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What do thiazide diuretics do?

A

Block Na-Cl transporter in DCT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are thiazide diuretics used to treat?

A

Hypertension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

True or false: blocking Na+ in DCT increases Ca2+ absorption and decreases Ca2+ loss in urine

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where do potassium sparing diuretics act?

A

Late DCT and CD on ENaC channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the two types of potassium sparing diuretics?

A
  • ENaC inhibitors (amiloride)

- aldosterone antagonists (spironolactone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

True or false: aldosterone antagonists reduce mortality in heart failure

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How can potassium loss be minimised?

A

Using potassium sparing diuretics with potassium losing diuretics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What can aldosterone antagonists be used to treat?

A
  • heart failure
  • ascites and oedema in cirrhosis
  • hypertension due to primary hyperaldosteronism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the rate of potassium secretion in the DCT and CD depend on?

A
  • conc gradient across apical membrane

- rate of Na+ absorption as inward movement of Na+ creates a negative lumen potential for K+ secretion

17
Q

How can loop and thiazide diuretics lead to hypokalaemia?

A

1) block Na+ and water reabsorption in LoH and DCT -> increased Na+ and water to late DCT and CD -> increased Na+ absorption by principal cells -> gradient for K+ excretion -> hypokalaemia
2) block Na+ and water reabsorption in LoH and DCT -> increased Na+ and water to late DCT and CD -> faster flow of filtrate in lumen -> K+ in lumen washed away faster -> favourable conc gradient for K+ secretion -> hypokalaemia

18
Q

How can ENaC inhibitors lead to hyperkalaemia?

A

Block ENaC -> decreased Na+ reabsorption -> decreased K+ loss in urine -> hyperkalaemia

19
Q

How can aldosterone antagonists lead to hyperkalaemia?

A

Block aldosterone action -> reduce Na/K ATPase and ENaC activity -> decreased Na+ reabsorption -> decreased K+ loss in urine -> hyperkalaemia

20
Q

When are diuretics used?

A

To treat conditions with ECF expansion and oedema

21
Q

How does congestive heart failure lead to ECF expansion?

A

Decreased CO with decreased renal perfusion or increased systemic venous pressure -> oedema -> RAAS activation -> Na+ and water retention -> ECF expansion

22
Q

How does nephrotic syndrome lead to ECF expansion?

A

Increased glomerular basement membrane permeability to protein -> proteinuria -> decreased plasma albumin -> decreased plasma oncotic pressure -> peripheral oedema -> decreased circulating volume -> RAAS -> Na and water retention -> ECF expansion

23
Q

What are the adverse effects of diuretics?

A
  • K+ abnormalities
  • hyponatraemia
  • dehydration
  • increased uric acid -> gout
  • glucose intolerance
  • erectile dysfunction with thiazides
  • breast enlargement with spironolactone
24
Q

How do carbonic anhydrase inhibitors work?

A

Act on PCT to inhibit CA action in brush border and PCT

25
Q

What are carbonic anyhdrase inhibitors used to treat?

A

Glaucoma as it decreases formation of aqueous humour

26
Q

How can carbonic anhydrase inhibitors cause metabolic acidosis?

A

Loss of HCO3- in urine

27
Q

How do osmotic diuretics work?

A

Small inert molecules which increase plasma osmolarity and draw fluid out from tissues and cells

28
Q

Give an example of an osmotic diuretic

A

Mannitol

29
Q

Which day-to-day substances have a diuretic effect?

A
  • alcohol

- Coffee

30
Q

Which diseases cause diuresis?

A
  • diabetes mellitus
  • diabetes insipidus: cranial or nephrogenic
  • psychogenic polydipsia
31
Q

What is the difference between cranial and nephrogenic diabetes insipidus?

A
  • cranial: decreased ADH from posterior pituitary

- nephrogenic: poor response of CD to ADH

Semester 3-Urinary (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions