Sodium Disturbances

Question 1

What is the normal sodium concentration?

Answer 1

Na 135-145

Question 2

Normal urine osmolality

Answer 2

<100mosm/kg

Question 3

Normal serum osmolality

Answer 3

285 mosm/kg

Question 4

What is the pathophysiological response to plasma hypotonicity

Answer 4

Sensed by hypothalamus - reduces synthesis of ADH - Diminished ADH in circulation - Fewer water channels in the kidney - creates water impermeable conduit - prevents water reabsorption - allows excretion of dilute urine

Question 5

Pathophysiological response to plasma hypertonicity

Answer 5

Higher concentration of ADH - higher water permeability - excretion of concentrated urine

Question 6

Non-osmotic causes of vasopressin release

Answer 6

Baroreceptors, Pain, stress, nausea, hypoxia, hypercapnea, medications

Question 7

What are the three types of hyponatremia

Answer 7

Isotonic, hypotonic, hypertonic

Question 8

Low Na+ and normal serum osmolarity

Answer 8

Isotonic hyponatremia

Question 9

Causes of isotonic hyponatremia

Answer 9

Artifact, hypertriglyceride, paraproteinemia

Question 10

Low Na+ and high serum osmolarity

Answer 10

Hypertonic Hyponatremia

Question 11

Low Na+ and decreased serum osmolarity

Answer 11

Hypotonic Hyponatremia

Question 12

What are the three types of hypotonic hyponatremia?

Answer 12

Euvolemic, Hypovolemic, Hypervolemia

Question 13

Hypotonic Euvolemic hyponatremia definition

Answer 13

Low Na+, low osmolarity, with clinically normal volume

Question 14

Causes of Euvolemic Hypotonic Hyponatremia

Answer 14

SIADH
Hypothyroidism
Glucocorticoid insufficiency
Medications
Reset osmstat syndrome

Question 15

What is the pathophysiology behind hypotonic hypovolemic hyponatremia

Answer 15

Low Na+, low osmolarity, clinically low volume
Impaired urinary diluting mechanism

Question 16

Causes of hypovolemic hypotonic hyponatremia

Answer 16

Hemhorrage, vomiting, diarrhea, diuretics, renal sodium wasting, cerebral salt wasting

Question 17

What is the normal level of urine sodium concentration and what do we see in hypotonic hypovolemic, hyponatremia

Answer 17

Normal: 40-220
Abnormal: <10

Question 18

Causes of hypotonic Hypervolemic hyponatremia

Answer 18

Renal failure
CHF
Cirrhosis
Nephrotic syndrome
Compromised renal diluting ability

Question 19

Serum Osmolality 280-295 with hyponatremia

Answer 19

Pseudohyponatremia

Question 20

Serum osmolality >295 with hyponatremia

Answer 20

Hypertonic hyponatremia

Question 21

Osmolarity <280 with hyponatremia

Answer 21

Hypotonic hyponatremia

Question 22

What does a urine osmolarity <100 and >100 indicate

Answer 22

<100: primary polydipsia or potomania
>100: assess patient volume status

Question 23

What is the goal Na+ correction rate and limit for correction?

Answer 23

Rate of correction: 4-6 mEq/L/24hrs
Limit: 6-8 meq/L/24 hours

Question 24

What is the risk of rapid sodium correction?

Answer 24

Osmotic demyelination syndrome

Question 25

How to correct chronic hyponatremia (>48hrs)

Answer 25

Slow, avoid rapid shifts Severely chronic are at high risk for demyelination In this case give DDAVP and dextrose 5%

Question 26

Treatment for mild to moderate hypotonic hyponatremia

Answer 26

Treat underlying cause

Question 27

When can sodium be corrected quickly

Answer 27

Post-op acute changes or acute seizures

Question 28

How to treat severe hyponatremia with seizures

Answer 28

#% hypertonic saline 100mls over 10mins Repeat only twice PRN Check BMP q1-2 hours Only treat until symptoms subside

Question 29

How to treat hypertonic hyponatremia

Answer 29

Treat underlying condition Most often HHS

Question 30

Hypotonic euvolemic hyponatremia treatment

Answer 30

Treat underlying condition If acute can be corrected quickly

Question 31

Hypotonic hypovolemic hyponatremia treatment

Answer 31

Fluid resuscitation with isotonic fluid, hold diuretics

Question 32

Hypotonic Hypervolemic Hyponatremia treatment

Answer 32

Loop diuretics, V2 receptor agonist (Tolvaptan, do not give in cirrhosis)

Question 33

Management for cerebral salt wasting

Answer 33

Hypertonic solution

Question 34

SIADH treatment plan

Answer 34

Withhold medications, fluid resuscitation, increase solute intake (salt tabs), diuretics

Question 35

How to treat psychogenic polydipsia

Answer 35

Fluid restriction

Question 36

What is the most common cause of sustained hypernatremia

Answer 36

Hospital setting fluid administration

Question 37

S/s of hypernatremia

Answer 37

Weakness, lethargy, confusion, seizures, coma, dehydration, orthostatic hypotension, oliguria, change in LOC, osmotic cerebral demyelination

Question 38

What are the main causes of euvolemic hypernatremia

Answer 38

Pure water loss, Central DI, Nephrogenic DI

Question 39

What is the primary characteristic lab findings for DI

Answer 39

Hypernatremia with urine osmo <250

Question 40

S/s of hypovolemic hypernatremia

Answer 40

Orthostatic hypotension, tachycardia, decreased organ perfusion

Question 41

Common causes of hypovolemic hypernatremia

Answer 41

Loss of GI fluids, diuretics, vigorous exercise If the Cl is <10 then it could be cutaneous or GI causes, extrarenal

Question 42

Causes and signs and symptoms of Hypervolemic hypernatremia

Answer 42

Administration of hypertonic sodium salts S/S: hypertension, edema, CHF

Question 43

Treatment of hypernatremia fluid management

Answer 43

Goal to lower Na+ by <10 mmols/L/day, BMP q4-6hrs D5% if unable to swallow 0.45% saline or isotonic Avoid sterile water can cause hemolysis

Question 44

Hypovolemic Hypernatremia treatment

Answer 44

Isotonic fluid then switch to hypotonic once volume resuscitation is complete

Question 45

Euvolemic Hypernatremia treatment

Answer 45

Water ingestion or 5% Dextrose, diuretics If CDI suspected give DDAVP NDI suspected give thiazide diuretic with COX inhibitor

Question 46

Hypervolemia Hypernatremia treatment

Answer 46

D5%, loop diuretics, Dialysis