HypoNa

Question 0

Symptoms of hyponatremia usually do not develop until serum sodium level reaches? Clinical Manifestations?

Answer 0

Low 120s. Cerebral edema, lethargy, confusion, seizures, or coma

Question 1

Most common electrolyte disturbance among hospitalized patients? Defined by?

Answer 1

Hyponatremia. Defined by serum sodium level less than 135

Question 2

Serum osmolarity: Hypernatremia versus hyponatremia?

Answer 2

Always hyperosmolality
versus
hyper-, normal, or hypo-osmolality

Question 3

What does it mean to have hyponatremia with hyper- or normal osmolarity?

Answer 3

Pseudohyponatremia.

If normal osmolarity: hyperproteinemia, hyperglycemia, Post transurethral resection of prostate

If hyperosmolar: hyperglycemia, mannitol

Question 4

Hyponatremia is most commonly associated with what type of state?

Answer 4

Hypo osmolar state

Question 5

Hyperosmolar hyponatremia is most often caused by?

Answer 5

Molecule that is stuck in the extracellular space and cannot cross cell membranes (Glucose, mannitol)

Question 6

Hyponatremia from hyperglycemia occurs in what setting? Relationship between glucose and Na?

Answer 6

Uncontrolled diabetes. Each 100 increase in serum glucose leads to a 1.6 decrease in serum sodium

Question 7

Surgical procedure that is a common cause of hyponatremia because of fluid used in intra- operatively?

Answer 7

Transurethral resection of the prostate because of the large volume of mannitol irrigation

Question 8

Pseudohyponatremia?

Answer 8

Artifact of measurement where high-protein levels or high lipid levels interfered with serum sodium level (Not an issue with current laboratory techniques)

Question 9

Hypotonic hyponatremia occurs because of?

Answer 9

Water gain from an attempt to maintain effective circulating volume or in SIADH

(Caused from impairment of free water excretion - Difficult to overwhelm kidney excretion ability simply with excessive intake)

Question 10

In hypovolemia, urine sodium level should be? Otherwise?

Answer 10

Less than 10-20 mmol/L. Otherwise kidneys do not have the ability to retain sodium normally

Question 11

Causes of hypervolemia? Mech?

Answer 11

CHF, liver cirrhosis, nephrotic syndrome.

Excess of sodium and water but baroreceptors perceive hypoperfusion. Leads to an increasing ADH and retention of more water

Question 12

Renal failure can lead to hypotonic hyponatremia because? Tx?

Answer 12

Inability to excrete dilute urine. diuretics

Question 13

Patient with euvolemic hyponatremia. Next step?

Answer 13

Measure urine osmolarity to determine if kidney is excreting free water normally (less than 100 mmol/L)

Question 14

Patient with euvolemic hyponatremia with maximally dilute urine. Diagnosis?

Answer 14

Central polydipsia (kidney is handling free water normally but its capacity for excretion has been overwhelmed)

Question 15

Patient with euvolemic hyponatremia with less than maximally dilute urine. Ddx?

Answer 15

Hypothyroidism, adrenal insufficiency or SIADH

Question 16

Effect of thyroid hormone and cortisol on free water excretion?

Answer 16

Increases free water excretion (deficiency causes water retention)

Question 17

Isolated cortisol deficiency can mimic? (Regarding Na)

Answer 17

SIADH

Question 18

Patients with adrenal insufficiency present with? (Vitals, labs, symptoms, exam findings)

Answer 18

Vitals: low BP
Labs: hyperkalemia and acidosis Sx: fatigue, weight loss
Exam: hyperpigmentation

Question 19

Euvolemic hyponatremia is most commonly caused by? Occurs in what settings?

Answer 19

SIADH. Pulmonary disease, CNS disease, pain, post operatively, paraneoplastic syndrome

Question 20

In order to be diagnosed with SIADH, need?

Answer 20

1. Hypoosmolar but euvolemic,
2. Urine that is not maximally dilute (osmolarity>150)
3. urine sodium more than 20
4. normal adrenal thyroid function

Question 21

Laboratory tests that will suggest SIADH? Tx?

Answer 21

Low BUN and low uric acid levels. Water restriction.

Question 22

SIADH patients with neurological symptoms should be treated with?

Answer 22

Hypertonic (3%) saline (not NS)

Question 23

When using hypertonic saline solution, if concerned about volume overload, administer i fusion with?

Answer 23

Furosemide or another loop diuretic. Diuretic causes excretion of hypotonic urine resulting in a greater portion of sodium than water being retained

Question 24

Central Pontine myelinolysis caused by? Can lead to?

Answer 24

Rapid correction of hyponatremia. May cause quadriplegia, pseudobulbar palsies, locked in syndrome

Question 25

Avoid osmotic cerebral demyelination by?

Answer 25

Not correcting the serum sodium concentration faster than .5 to 1 mEq/hr

Question 26

Why does hyponatremia occur after surgery?

Answer 26

Operations increase AVP

Question 27

Hypovolemic patients with hyponatremia should be treated with?

Answer 27

0.9 saline solution

Question 28

Euvolemic patients with asymptomatic hypernatremia should be treated with?

Answer 28

Fluid restriction

Question 29

HyperNa patients with severe symptoms such as coma or seizures should be treated with?

Answer 29

Hypertonic (3%) saline