Distal Renal Tubular Disorders - Ault Flashcards Preview

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Flashcards in Distal Renal Tubular Disorders - Ault Deck (38):
1

What are the targets of the following drugs?

Acetazolamide

Furosemide, bumetanide, ethacrynic acid

Thiazide

Amiloride, tramterene

Spironolactone, eplerenone

Acetazolamide - carbonic anhydrase

Furosemide, bumetanide, ethacrynic acid - Na-K-2Cl

Thiazide - NaCl

Amiloride, tramterene - ENaC

Spironolactone, eplerenone - Mineralocorticoid receptor

2

What are the mutations present in Bartter syndrome?

N-K-2Cl

ROMK

Cl- channel (CLCNKA, CLCNKB)

Barttin (Cl channel)

3

What are the mutations present in Gitelman Syndrome?

Thiazide-sensitive NaCl channel

4

What are the mutations in Liddle Syndrome?

Gain of function in ENaC

5

What is TTKG and what is the equation?

Transtubular Potassium Gradient

TTKG = (UK * Posm) / (PK * Uosm)

6

What are expected values of the TTKG in hypokalemia and hyperkalemia?

Hypokalemia < 2

Hyperkalemia > 8

7

What is the effect of hyperaldosteronism on potassium?

Hypokalemia

8

What are causes of hyperaldosteronism?

Primary (tumors)

Dehydration (pyloric stenosis)

Sodium-wasting disorders (Bartter-Gitelman)

Glucocorticoid-remediable hyperaldosteronism (GRA)

Apparent mineralocorticoid excess (AME)

9

What is the cause of glucocorticoid-remediable hyperaldosteronism (GRA)?

Recombination protducing hybrid molecule that makes ldosterone in response to stress

10

What are the effects of glucocorticoid-remediable hyperaldosteronism (GRA)?

Low renin hypertension

Hypokalemia

11

What is the cause of apparent mineralocorticoid excess (AME)?

Increased renal cortisol

12

What are the effects of apparent mineralocorticoid excess (AME)?

13

What is the effect of hypoaldosteronism and pseudohypoaldosteronism on potassium?

Hyperkalemia

14

What are the causes of hypoaldosteronism?

Congenital adrenal hypoplasia

Congenital adrenal hyperplasia

Autoimmune

15

What are the causes of pseudohypoaldosteronism?

PHA Type I

PHA Type II

Tubular injury (obstructive uropathy)

16

What are symptoms of PHA Type I?

Hyperkalemia

Hyponatremia

Hypotension

17

What are the causes of PHA Type I?

Mutation in mineralocorticoid receptor

Loss of function of ENaC

18

What is the treatment of PHA Type I?

Sodium supplements

High fluid intake

K-binding resin

19

What are symptoms of PHA Type II?

Hyperkalemia

Hyperchloremic metabolic acidosis

Hypertension

"Gordon syndrome"

20

What are the causes of PHA Type II?

Mutations in NaCl cotransporter

21

What is the treatment of PHA Type II?

Thiazide diuretics

22

What should you check first in metabolic acidosis?

Plama anion gap

Na - (Cl + CO2)

23

What causes elevated anion gap acidosis?

Ketoacidosis

Lactic acidosis

Metabolic errors

Poisons (ethylene glycol)

24

What causes normal anion gap acidosis (hyperchloremic metabolic acidosis)?

GI losses of bicarbonate

Exogenous chloride

Renal tubular acidosis

25

What principle does TTKG measure?

Aldosterone response in hypo/hyper kalemia

26

What is the anion gap in RTA?

Normal anion gap acidosis

27

What are the types of RTA?

Type II (proximal) - associated with Fanconi

Type I (classical distal) - very rare

Type IV (hyperkalemic) - syndrome of aldosterone deficiency

28

What are the tests for RTA?

Fractional excretion of bicarbonate

Urine pH

Urine anion gap

U-B PCO2

29

What are the fractional excretions of bicarbonate in each type of RTA?

Type I (classical distal) - <5%

Type II (proximal) - >10-15%

Type IV (hyperkalemic) - <5-10%

30

What is the urine pH in each type of RTA?

Type I (classical distal) - >5.5 

Type II (proximal) - <5.5

Type IV (hyperkalemic) - either

31

What is the equation for urine anion gap?

Na + K - Cl

32

What is the value of the urine anion gap in diarrhea?

Negative

33

What is the value of the urine anion gap in RTA?

Positive

34

What is the U-B PCO2?

Measure of secreted CO2 following a HCO3 load

35

What are the results of a U-B PCO2 in each type of RTA?

Type I (classical distal) - <10-15

Type II (proximal) - 10-15

Type IV (hyperkalemia) - <10-15

36

What is a distinguishing feature of Type II (proximal) RTA?

Fanconi syndrome

37

What is a distinguishing feature of Type IV (hyperkalemic) RTA?

High plasma K

38

What causes RTA type IV?

Mineralocorticoid deficiency / resistance

Renal tubular dysfunction