Physiology Correlations for Mendelian Forms of Hypertension Flashcards Preview

Renal > Physiology Correlations for Mendelian Forms of Hypertension > Flashcards

Flashcards in Physiology Correlations for Mendelian Forms of Hypertension Deck (27):
1

Describe the presentation of AME (Syndrome of Apparent Mineralocorticoid excess)

  • Low birth weight
  • Failure to thrive
  • Severe hypertension in early childhood
  • Extensive organ damage
  • Renal failure

2

In AME, what happens with plasma renin and aldosterone levels?

Low plasma renin activity

Low plasma aldosterone levels

3

What gene defect is seen in AME?

11-ß-HSD2 gene

4

What is the function of 11-ß HSD2?

How does its function aid in diagnosis of AME?

Converts cortisol to cortisone

Meausre urine cortisol to cortisone ratio - in most patients with a defective enzyme, the urinary free cortisone levels are very low or undetectable

5

What type of inheritance is associated with AME?

Autosomal recessive

6

Liddle syndrome is also known as ____________

Pseudoaldosteronism

7

What characteristics are associated with pseudoaldosteronism?

  • Hypertension - young onset, severe
  • Hypokalemia
  • Metabolic Alkalosis

8

What RAA system components have low levels and activity in pseudoaldosteronism (Liddle syndrome)

Low plasma renin activity

Low plasma aldosterone AND urinary aldosterone

9

What genes can be sequenced to confirm the diagnosis of Pseudoaldosteronism

SCNN1G

SCNN1B

10

Liddle syndrome is associated with a _____ __ ______mutation in the renal _____ channel 

gain of function; ENaC

11

Mutations in LIddle Syndrome lead to increased absorption of _______ leading to hypertension

sodium

12

Where does aldosterone act and what function does it serve?

  • Acts in principal cells of late distal tubule and collecting duct
  • Increases Na+ reabsorption , increases K+ secretion

13

Cortisol and aldosterone can bind to the mineralcorticoid receptor with equal affinity but aldosterone is the primary effector. Why is this?

Cortisol is quickly converted to cortisone upon entering into the cell

A image thumb
14

What medication is used to reduce endogenous cortisol production (decrease sodium channel activity) in AME?

Amiloride

Triamterene

15

What medications block the mineral corticoid receptor in AME?

Spironolactone

Eplerenone

16

Other therapies for AME treatment?

Potassium repletion

Dexamethasone for ACTH suppression

17

How does Bartter syndrome present?

  • Early childhood
  • Growth and mental retardation
  • Polyuria and Polydipsia
  • Hypercalciuria

18

How does Gitelman syndrome present?

  • Adolescence/Adulthood
  • Cramping of arms and legs
  • Fatigue
  • Hypomagnesemia
  • Polyuria and nocturia

19

What are the clinical findings in Bartter syndrome?

Hypokalemia

Hyperreninemia

Hyperaldosteronism

Metabolic Alkalosis

20

What pattern of inheritance is associated with Gitelman syndrome?

Autosomal recessive

21

Which portion of the renal tubule has the following characteristics...

Reabsorbs 25% of filtered Na+

Impermeable to water

Drives reabsorption of sodium, potassium, magnesium, and calcium

Thick ascending loop of Henle

22

What part of the renal tubule is succeptible to thiazide diuretics?

Early distal tubule

23

What genes are mutated in Bartter syndrome?

Genes that encode proteins in the ascending part of Henle's loop:

BSND, CLCNKA, CLCNKB, KCHJ1, SLC12A1

24

What genes are mutated in Gitelman Syndrome?

Mutations in SLC12A3 or less commonly CLCNKB

25

In Bartter syndrome, tubular defect mimics chronic _____ _______ injestion

loop diuretic

26

In Gitelman syndrome, tubular defect mimics ______ _______ ingestion

thiazide diuretic

27

Which disease (Bartter syndrome or Gitelman syndrome) has a worse prognosis?

Bartter syndrome (life expectancy is reduced in severe cases)