Im Renal Fluids & Sodium Usmle 2

Front 1

(3) major toxins that increase the serum's osmolarity

Back 1

EtOH

Methanol

Ethylene glycol

Front 2

ICF is what fraction of TBW?

Major cations of ICF? (2)

Major anions? (2)

Back 2

ICF = 2/3 of TBW

Cations:
K
Mg

Anions:
Proteins
Oranic Phosphates (ATP, ADP, AMP)

Front 3

ECF is what fraction of TBW?

Major cation of ECF?

Major anions? (2)

Back 3

ECF = 1/3 of TBW

Cation:
Na

Anions:
Cl
HCO3

Front 4

What composition does interstitial fluid resemble?
What is different?

Back 4

resembles Plasma

Interstitial fluid contains little protein (ultrafiltrate)

Front 5

What (2) compartments does water shift between?

If solutes (glucose, sodium, mannitol) dont cross the cell membrane, what osmolarity do they contribute to?

Back 5

ECF + ICF

ECF

Front 6

Formula for Serum Osmolarity

Normal Serum Osmolarity?

Back 6

SO = 2(Na+K) + Glucose/18 + BUN/2.8

300 mOsm/kg

Front 7

Define:

HypoN

Back 7

plasma sodium < 134mEq/L

Front 8

What are the (3) categories of HypoN?

Back 8

Hypovolemic

Isovolemic

Hypervolemic

Front 9

How can you distinguish b/t renal and extrarenal causes of hypovolemic hypoN?

Back 9

Urine Sodium:

U-Na > 20 = Renal

U-Na < 10 = Non-renal

Front 10

Extra-renal causes of hypovolemic hypoN
(5)

Back 10

GI loss (Vomiting/Diarrhea)

Extensive burns

Dehydration

3rd spacing (pancreatitis, peritonitis)

Hint 10

GED 3

Front 11

Renal causes of Hypotonic Hypovolemic HypoN
(5)

Back 11

TANAS:
Thiazides (diuretics);
ACEi;
Nephropathies;
Addisons Dz (Mineralcorticoid deficiency);
Salt-wasting nephropathies

Hint 11

TANAS

Front 12

Etiology of Hypotonic Euvolemic HypoN
(separate into 2 categories - 8 total)

Back 12

Less dilute urine (SHiT):
SIADH
Hypothyroidism
Idiosyncratic drug rxn (Thiazides, ACEi)

More dilute urine (Huge PEPE):
HypoK
Post-op HypoN
EtOH addiction
Psychogenic polydipsia
Exercise

Hint 12

SHiT
Huge PEPE

Front 13

"tonic" as in hypertonic refers to what?

Back 13

serum osmolality

Front 14

Serum osmolality level for:

HypoN

HyperN

Back 14

HypoN: < 280 mOsm/kg

HyperN: > 300 mOsm/kg

Front 15

Etiology of Hypotonic Hypervolemic HypoN
(4)

Back 15

CLAN:
CHF
Liver disease
Advanced Renal Failure
Nephrotic syndrome

Hint 15

CLAN

Front 16

Etiology of Isotonic HypoN
(2)

Back 16

Hyperproteinemia

Hyperlipidemia

Front 17

Etiology of Hypertonic HypoN
(2)

Back 17

Facticious HypoN:

Hyperglycemia

Hypertonic infusions
(mannitol, glucose, contrast)

Front 18

How does each 100 mL/dL increase in serum glucose above normal cause sodium to decrease?

Back 18

Sodium decreases by 1.6 mEq/L

Front 19

Signs/Sx of moderate hypoN or gradual onset
(4)

Back 19

Confusion
Muscle cramps
Anorexia
Nausea

Hint 19

C-MAN

Front 20

Signs/Sx of severe hypoN or rapid onset
(2)

At what level is considered severe?

Back 20

Seziures or Coma

Severe: < 115 mEq/L

Front 21

With low serum osmolarity (< 280), what signs should be observed to differentiate b/t Hypovolemia, Isovolemia, & Hypervolemia?

Back 21

Hypovolemia:
Tachycardia; Hypotension; poor skin turgor

Isovolemia:
Normal vital signs w/o edema

Hypervolemia:
peripheral Edema

Front 22

Dx:
measured & calculated serum osmolarities are different

What (2) problems is it seen in?

Back 22

Pseudohyponatremia

Seen in:
Multiple myeloma
Hyperlipidemia

Front 23

Tx of Hypovolemic HypoN
(2)

Back 23

1. address underlying disorder

2. replace volume w/ NS
(monitor Na to prevent CPM)

Front 24

Tx of Isovolemic or Hypervolemic HypoN
(2)

Back 24

1. address underlying disorder

2. Sodium + water restriction

Front 25

What is Tx for CHF-induced Hypervolemic HypoN?
(2)

Back 25

1. Sodium + water restriction

2. Combination of Captopril & Furosemide

Front 26

Rules for correcting HypoN by increasing serum sodium
(2)

Why?

Back 26

1. only go into low-normal range in forst 24 hours

2. never correct sodium faster then 1 mEq/L/hr

Can lead to Central Pontine Myelinolysis (CPM), seizures, coma

Front 27

What are pre-menopausal women at high risk for during an acute episode of HypoN?

Back 27

Cerebral edema

Front 28

Dx:
Osmotic demyelination syndrome occurring as a treatment complication of severe or chronic hypoN

Back 28

Central Pontine Myelinolysis
(CPM)

Front 29

Serum sodium level that is considered HyperN

Back 29

Serum Na > 145 mEq/L

Front 30

Type of HyperN:
Loss of both water + sodium
(water loss >> sodium loss)

Back 30

Hypovolemic HyperN

Front 31

Type of HyperN:
Decreased TBW, normal body sodium, decreased ECF

Back 31

Isovolemic HyperN

Front 32

Type of HyperN:
Increased TBW, markedly Inc total body Na, Inc ECF

Back 32

Hypervolemic HyperN

Front 33

Etiology of Hypervolemic HyperN
(3)

Back 33

Hypertonic fluid administration;

Mineralcorticoid excess (Cushing's, Conn's);

Excess salt ingestion

Front 34

Etiology of Isovolemic HyperN
(2)

Back 34

Diabetes Insipidus;

Skin losses (due to hyperthermia)

Front 35

Etiology of Renal-related Hypovolemic HyperN
(3)

Back 35

Diuretics;

Acute/chronic Renal failure;

Partial obstruction

Front 36

Etiology of Extra-renal-related Hypovolemic HyperN
(5)

Back 36

Hyperpnea;

Excessive sweating;

Diarrhea;

Burns;

Dialysis

Front 37

formula for Water Deficit in HyperN patient

Back 37

WD (liters) = 0.6 x body wt (kg) x (measured Na/140) -1

Front 38

Tx for Hypovolemic HyperN

Back 38

Fluid replacement w/ NS

(correct plasma osmolarity no faster then 2 mOsm/kg/hr)

Front 39

Tx for Isovolemic HyperN

What additionally should you do if Dx is Central Diabetes Insipidus?

Back 39

Fluid replacement w/ 1/2 NS
(correct only half of the deficit in first 24 hrs)

C-DI: Vasopressin

Front 40

Tx for Hypervolemic HyperN
(2)

Back 40

1. Fluid replacement w/ 1/2 NS (for hypertonicity)

2. Loop diuretic (furosemide) to inc Na excretion