L46 + 47 + SG 1

Question 1

What cannot pass the barrier between the intravasc and interstitial spaces?

Answer 1

No permeable to proteins

Ex: albumin is the main protein that prevents movement of fluid into interstitium

Question 2

What cannot pass the barrier between the interstitial and intracellular spaces?

Answer 2

No permeable to electrolytes b/c of the cell membrane

Goal to keep cells the same - maintain fxn

Question 3

Explain changes to Starling forces during heart failure leading to peripheral edema.

Answer 3

Heart = ineffective pump
Blood packs up into venous system
Increase hydrostatic pressure intravasc -> fluid forced into interstitium = EDEMA

Question 4

Define osmolality - inlcude units.

Answer 4

+ particles in 1 L water = mmol/L
Aka [ ] by number
Plasma osmolality = [electrolytes] + [nonelectrolytes]

Question 5

What are the 2 ways that the extracellular space can epand if extra volume is present?

Answer 5

1. Edema - duh, into interstitium (also look at lungs)

2. HTN if expand intravasc

Question 6

Describe scenarios in which there is volume overload (expand interstitium) but intravasc depletion

Answer 6

Lose oncotic pressure 
Total body Na increased 
- Cirrohsis w/ ascites
- Nephrotic syndrome 
- CHF
- Burns (lose protein via skin)

Question 7

What is step 1 of dx approach for hypo-osmolar states?

Answer 7

Posm: hypo, pseudo or hyper osmotic?

Question 8

What is step 2 of dx approach for hypo-osmolar states?

Answer 8

ECF assessment - hypo, eu, or hypervolemic

Question 9

4 causes on differential for euvolemic hypotonic hyponatremia

Answer 9

SIADH
Pysch pt downing H2O
Hypothyroidism
Drugs

Question 10

Equation to calculate Posm?

Answer 10

Posm = 2[Na] + (BUN/2.8) + (glucose/18)

Question 11

4 causes on differential for hypervol hypotonic hyponatremia

Answer 11

= pt really volume overloaded by intravasc depletion 
CHF
Cirrhosis 
Nephrotic syndrome 
Oliguric renal failure

Question 12

What are 5 key symptoms for dx of nephrotic syndrome?

Answer 12

1. Proteinuria = > 3.5gm/24 hrs
2. Hyperlipidemia - liver sees low ECV and throws fat to try to compensate
3. Lipiduria
4. Hypoalbuminemia
5. Edema (hypervol)

Question 13

What is the U Na cut off for renal vs non-renal causes of hypovol hyponatremia?

Answer 13

Renal: U Na > 20 = kidney is wasting Na even though you should be saving it
Non-renal: U Na

Question 14

3 causes on the differential for non renal hypovol hypotonic hyponatremia

Answer 14

1. GI losses: vomiting, diarrhea, fistula
2. Skin losses (burns)
3. Remote diuretic use

Question 15

4 causes on differential for renal hypovol hypotonic hypoNa

Answer 15

1. Acute diuretics
2. Salt wasting nephropathy
3. Adrenal insuff (Addison’s disease)
4. Osmotic diuretics

Question 16

4 factors necessary in nephron to excrete free water

Answer 16

1. Normal GFR
2. Distal delivery of Na past prox loop of Henle
3. Intact ascending loop
4. Suppress ADH

Question 17

What Uosm > x denotes a failure to suppress ADH?

Answer 17

Uosm > 100

Question 18

What happens to the 4 steps in the kidney during hypovol?

Answer 18

↑Prox tubule Na reabsorption - first step to fixing the prob fast but…
↓s Distal Na delivery
↓ Loop Na reabsorption
↓ Ability to suppress ADH

Question 19

What happens to the 4 steps in the kidney during euvolemia?

Answer 19

Only ↓ability to suppress ADH (think SIADH)

Question 20

What happens to the 4 steps in the kidney during hypervolemia?

Answer 20

Same as hypovol b/c intravasc hypervol!

Question 21

Symptoms of hyponatremia

Answer 21

Lethargy, apathy
Disorientation 
Muscle cramps
Anorexia/nausea 
Agitation

Question 22

Signs of hyponatremia

Answer 22

Depressed deep tendon reflexes
Hypothermia
Seizures
Pseudobulbar palsy

Question 23

Treat hypovol hypoNa

Answer 23

Saline

Question 24

Treat euvol hypoNa

Answer 24

Water restriction

2ary: V2 receptor antag

Question 25

Treat hypervol hypoNa

Answer 25

Water restriction

Maybe V2 antag and/or diuretics (for edema)

Question 26

What are you worried about if you correct hypoNa too fast?

Answer 26

Osmotic demyelination

Esp if chronic hypoNa

Question 27

What is pseudohypoNa?

Answer 27

More stuff in plasma so less water
Na/plasma vol = low
Pts w/ multiple myeloma, hyperlipidemia, hyperproteinemia, hyperglycemia (DKA)