Proximal Tubular Dysfunctions and Disorders of Water Balance - Gosmanova Flashcards Preview

Nephrology > Proximal Tubular Dysfunctions and Disorders of Water Balance - Gosmanova > Flashcards

Flashcards in Proximal Tubular Dysfunctions and Disorders of Water Balance - Gosmanova Deck (24):
1

Which segments of the PT secrete organic compounds?

S2 and S3

2

What are the types of transport mechanisms present in the PT?

Primary active
Secondary active
Passive
Pinoctyosis

3

What substances are reabsorbed via Na cotransport in the PT?

Sugars
Amino acids
Phosphate
Citrate

4

What substances are reabsorbed via Na antiport in the PT?

H

5

What does angiotensin II promote in the PT?

Na / H antiporter (luminal)
HCO3 / Na cotransport (basolateral)

6

What can cause a defect in glucose reabsorption?

Mutation of SGLT2 glucose transporter (Hereditary Renal Glucosuria)

7

What can cause a defect in amino acid reabsorption?

Mutation of brush border transporter for cystine, ornithine, lysine, and arginine
Cystinuria

8

What can cause a defect in phosphate reabsorption?

Mutation in PHEX gene (X-linked hypophosphatemia - most common)
Mutation in FGF-23 (Hypophosphatemic rickets)
Increased FGF-23 production (Oncogenic hypophosphatemic osteomalacia)

9

What is Fanconi syndrome?

Collection of symptoms (different underlying causes)
Aminoaciduria
Glucosuria
Hypophosphatemia
Hyperchloremic metabolic acidosis
Hypokalemia
Uricosuria

10

What is an inherited cause of Fanconi syndrome?

Cystinosis

11

What are acquired causes of Fanconi syndrome?

Drugs (Tenofovir)
Heavy Metals
Toxins
Dysproteinemias (Multiple myeloma)
Acute tubular necrosis

12

What is the normal osmotic threshold for ADH and thirst?

ADH 280-290
Thirst 290-295

13

What is osmolar clearance?

Amount of water needed to excrete solutes at the concentration of solutes in plasma

14

What is the most common electrolyte disorder?

Hyponatremia

15

What is hyperosmolar hyponatremia?

Dilutional hyponatremia due to presense of osmotically active substances (glucose, mannitol, glycine)

16

What is psudohyponatremia?

This occurs with increased solid phase of plasma and is an artifact of Na assays

17

What is true hyponatremia and what is the underlying mechanism?

Hypoosmolar hyponatremia
Impaired urinary dilution mechanisms

18

What are causes of hypovolemic hyponatremia?

Renal losses
GI losses
Skin losses
Third spacing (Pancreatitis, bowel obstruction, burns)

19

What causes euvolemic hyponatremia?

SIADH
Glucocorticoid deficiency
Hypothyroidism

20

What causes hypervolemic hyponatremia?

CHF
Acute / Chronic kidney failure
Cirrhosis
Nephrotic syndrome

21

How can you differentiate psychogenic polydipsia and SIADH?

Urine osmolality
Polydipsia - Low
SIADH - high

22

What is the main defense against hypernatremia?

Thirst

23

What is polyuria?

> 3 L urine / day

24

What are two differences between DI and polydipsia?

DI - high Posm and 500 Uosm in response to water deprivation