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Flashcards in HypoNa Deck (30)
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0
Q

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

A

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

1
Q

Most common electrolyte disturbance among hospitalized patients? Defined by?

A

Hyponatremia. Defined by serum sodium level less than 135

2
Q

Serum osmolarity: Hypernatremia versus hyponatremia?

A

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

3
Q

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

A

Pseudohyponatremia.

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

If hyperosmolar: hyperglycemia, mannitol

4
Q

Hyponatremia is most commonly associated with what type of state?

A

Hypo osmolar state

5
Q

Hyperosmolar hyponatremia is most often caused by?

A

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

6
Q

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

A

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

7
Q

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

A

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

8
Q

Pseudohyponatremia?

A

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

9
Q

Hypotonic hyponatremia occurs because of?

A

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)

10
Q

In hypovolemia, urine sodium level should be? Otherwise?

A

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

11
Q

Causes of hypervolemia? Mech?

A

CHF, liver cirrhosis, nephrotic syndrome.

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

12
Q

Renal failure can lead to hypotonic hyponatremia because? Tx?

A

Inability to excrete dilute urine. diuretics

13
Q

Patient with euvolemic hyponatremia. Next step?

A

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

14
Q

Patient with euvolemic hyponatremia with maximally dilute urine. Diagnosis?

A

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

15
Q

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

A

Hypothyroidism, adrenal insufficiency or SIADH

16
Q

Effect of thyroid hormone and cortisol on free water excretion?

A

Increases free water excretion (deficiency causes water retention)

17
Q

Isolated cortisol deficiency can mimic? (Regarding Na)

A

SIADH

18
Q

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

A

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

19
Q

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

A

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

20
Q

In order to be diagnosed with SIADH, need?

A
  1. Hypoosmolar but euvolemic,
  2. Urine that is not maximally dilute (osmolarity>150)
  3. urine sodium more than 20
  4. normal adrenal thyroid function
21
Q

Laboratory tests that will suggest SIADH? Tx?

A

Low BUN and low uric acid levels. Water restriction.

22
Q

SIADH patients with neurological symptoms should be treated with?

A

Hypertonic (3%) saline (not NS)

23
Q

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

A

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

24
Q

Central Pontine myelinolysis caused by? Can lead to?

A

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

25
Q

Avoid osmotic cerebral demyelination by?

A

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

26
Q

Why does hyponatremia occur after surgery?

A

Operations increase AVP

27
Q

Hypovolemic patients with hyponatremia should be treated with?

A

0.9 saline solution

28
Q

Euvolemic patients with asymptomatic hypernatremia should be treated with?

A

Fluid restriction

29
Q

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

A

Hypertonic (3%) saline

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