Renal Tubular Defects

Question 1

Fanconi syndrome defects

Answer 1

generalized reabsorption defect in PCT -> increase excretion of amino acids, glucose, HCO3- and PO4-3, and all substances reabsorbed by the PCT

Question 2

Fanconi syndrome effects

Answer 2

may lead to metabolic acidosis (proximal RTA), hypophosphatemia, osteopenia

Question 3

Fanconi syndrome causes

Answer 3

hereditary defects (Wilson disease, tyrosinemia, glycogen storage disease), ischemia, multiple myeloma, nephrotoxins/drugs (ifosfamide, cisplatin, expired tetracyclines), lead poisoning

Question 4

Bartter syndrome defects

Answer 4

resorptive defect in thick ascending loop of Henle (affects Na+/K+/2Cl- cotransporter)

Question 5

Bartter syndrome effects

Answer 5

metabolic alkalosis, hypokalemia, hypercalciuria

Question 6

Bartter syndrome causes

Answer 6

autosomal recessive

Question 7

Bartter syndrome notes

Answer 7

presents similarly to chronic loop diuretic use

Question 8

Gitelman syndrome defects

Answer 8

reabsorption defect of NaCl in DCT

Question 9

Gitelman syndrome effects

Answer 9

metabolic alkalosis, hypomagnesemia, hypokalemia, hypocalciuria

Question 10

Gitelman syndrome causes

Answer 10

autosomal recessive

Question 11

Gitelman syndrome notes

Answer 11

presents similarly to lifelong thiazide diuretic use

less severe than Bartter syndrome

Question 12

Liddle syndrome defects

Answer 12

gain of function mutation -> increase activity of Na+ channel -> increase Na+ reabsorption in collecting tubules

Question 13

Liddle syndrome effects

Answer 13

metabolic alkalosis, hypokalemia, hypertension, decrease aldosterone

Question 14

Liddle syndrome causes

Answer 14

autosomal dominant

Question 15

Liddle syndrome notes

Answer 15

presents similarly to hyperaldosteronism, but aldosterone is nearly undetectable
treat with amiloride

Question 16

syndrome of apparent mineralocorticoid excess defect

Answer 16

in cells containing mineralocorticoid receptors, 11beta-hydroxysteroid dehydrogenase converts cortisol (can activate these receptors) to cortisone (inactive on these receptors)
hereditary deficiency of 11beta-hydroxysteroid dehydrogenase -> excess cortisol -> increase mineralocorticoid receptor activity

Question 17

syndrome of apparent mineralocorticoid excess effects

Answer 17

metabolic alkalosis, hypokalemia, hypertension, decrease serum aldosterone level; cortisol tries to be the SAME as aldosterone

Question 18

syndrome of apparent mineralocorticoid excess causes

Answer 18

Autosomal recessive
can acquire disorder from glycyrrhetinic acid (present in licorice), which blocks activity of 11beta-hydroxysteroid dehydrogenase

Question 19

syndrome of apparent mineralocorticoid excess notes

Answer 19

treat with K+-sparing diuretics (decrease mineralocorticoid effects) or corticosteroids (exogenous corticosteroid decrease endogenous cortisol production -> decrease mineralocorticoid receptor activation)