Electrolytes Flashcards
What is the most common electrolyte abnormality?
Hyponatremia
What is the most common cause of hypokalemia?
Renal loss
What are the ECG findings in hypokalemia versus hyperkalemia?
Hypokalemia - Prolonged U wave and T wave inverts.
Hyperkalemia - Tall T, Wide QRS, Prolonged PR interval and wide and flat P.
How can you differentiate Bartter and Gitelman in terms of clinical findings and diagnostic findings?
Bartter - presents early in life, mimics loop diuretics, urinary calcium increased hence at risk for stones, renal PGE2 increased.
Gitelman - presents later in life, mimics thiazide diuretics, neuromuscular symptoms common, decreased urinary calcium and normal renal PGE2.
What is the mechanism of hypokalemia in patients taking insulin and catecholamines?
Activation of Na-K ATPase pump.
What is the first step in a patient with hyperkalemia?
Rule out pseudohyperkalemia
What is the most common cause of chronic hyperkalemia due to impaired renal excretion?
Hyporeninemic hypoaldosteronism
Remarks: Usual cause of this is diabetic nephropathy.
What is the mechanism of hyperkalemia in patients taking digitalis?
Inhibition of Na-K ATPase pump.
Remarks: same mechanism with bufotoxin, beta-blockers and chansu.
State if it causes enhanced or inhibited ADH release:
a. Beta catecholamines
b. Alpha catecholamines
c. Angiotensin II
d. Prostaglandins
e. Lithium
f. Conivaptan (V2 antagonist)
g. Thirst
h. Ethanol
i. Cortisol
j. Demeclocycline (antibiotic)
a. enhanced
b. inhibited
c. enhanced
d. inhibited
e. inhibited
f. inhibited
g. enhanced
h. inhibited
i. inhibited
j. inhibited
The reduction of serum Na from hemolysis is greater than the increase in serum K by how much/ by how many factors?
By a factor of 1.3
130%?
Hyponatremia becomes clinically significant at what value?
<130 mmol/L
Remarks: Hyponatremia definition <135 mmol/L
