Electrolyte Imbalances

Question 1

A patient has carpal spasm when a blood pressure cuff is inflated. Which diagnostic testing will the primary care provider consider to evaluate the cause of this finding?

Calcitriol level

Magnesium and vitamin D

Protein electrophoresis

C-reactive protein

Answer 1

Correct! The Trousseau’s sign indicates neuromuscular irritability, which occurs with hypocalcemia. Because hypomagnesemia and vitamin D deficiency may cause hypocalcemia, these should be evaluated to help determine a cause.

Question 2

Which test should be performed initially to assist with the differential diagnosis of a patient who has a serum potassium level of 3 mEq/L and a normal blood pressure?

Plasma aldosterone

Serum bicarbonate

Plasma renin activity

Serum magnesium

Answer 2

Correct! In patients with hypokalemia with normal blood pressure, serum bicarbonate should be assessed to evaluate for diabetic ketoacidosis, metabolic acidosis, or renal tubular acidosis. If bicarbonate is normal, serum magnesium may be assessed.

Question 3

Hypercalcemia

Answer 3

Ionized calcium >5.3 or corrected calcium > 10.5

Question 4

Hypocalcemia

Answer 4

Ionized calcium <4.4

Corrected calcium <8.5

Question 5

Hypercalcemia causes

Answer 5

Primary hyperparathyroidism, excess secretion of PTH

Renal failure, metabolic alkalosis, vitamin D excess

Question 6

Hypercalcemia Presentation

Answer 6

Neuromuscular, cardiac, GI depression
Short QT interval, heart blocks
Constipation, N/V

Question 7

Hypocalcemia Presentation

Answer 7

Muscle weakness, tetany, convulsions
Seizures, cataracts, hyper-reflexia (Chvostek / Trousseau signs)
Parkinson like tremors
Hypotension, bradycardia
Chronic = coarse hair, brittle nails, scaly skin

Question 8

Chronic Hypocalcemia

Answer 8

Significant Vitamin D deficiency is usually the cause
‘Hungry bone syndrome’
Hypoparathyroid

Question 9

Calcium disturbance Referral

Answer 9

Any symptomatic calcium disturbances need ED refer

For severe hypocalcemia treat with calcium gluconate immediatley

Question 10

Hypocalcemia Treatment

Answer 10

Vitamin D therapy for chronic hypocalcemia

Calcium supplements as needed

Question 11

Hypercalcemia treatment

Answer 11

For mild - hydration and avoidance of things that worsen it

Severe = ICU admit, aggressive fluids to prompt urine dilution
May require dialysis

Question 12

Hypokalemia Presentation

Answer 12

Clinical signs and symptoms of acute hypokalemia include: weakness, palpitations, nausea, vomiting, hypotension, metabolic alkalosis, potassium less than 2.5, and EKG changes. EKG changes in hypokalemia include flattened T waves, the presence of U waves, ST depressions, and ventricular arrhythmias

Question 13

Normal Potassium Range

Answer 13

3.5 - 5

Question 14

Causes of Potassium Disturbances

Answer 14

Both hyper- and hypokalemia can result from potassium redistribution within the body’s cells. Hyperkalemia can also result from impaired renal excretion or increased intake. Hypokalemia can result from increased potassium losses (renal or extrarenal) or from decreased potassium intake. Pseudo hyper- and hypokalemia are not uncommon and must always be ruled out.

Question 15

Hyperkalemia Presentation

Answer 15

chiefly cardiac and are best monitored by EKG.
Progressive EKG changes seen in hyperkalemia are peaked T waves, PR prolongation, intraventricular block, sine waves, and ultimately ventricular fibrillation and asystole.
Severe hyperkalemia can cause muscle weakness and rarely ascending paralysis as seen in hypokalemia

Question 16

Hypokalemia Causes

Answer 16

• Cellular redistribution
• Extrarenal loss
• renal loss
• decreased intake
• Pseudo-hypokalemia (hemolysis of sample)

Question 17

Hyperkalemia Causes

Answer 17

• Cellular redistribution
• Decreased renal excretion
• excess intake
• Pseudo hyperkalemia (bad lab sample)

Question 18

Medications that cause redistribution

Answer 18

Insulin, Beta agonists, decongestants, verapamil, xanthines, laxative, diretics = hypokalemia

ACE-I, ARBs, NSAIDs, K sparing diuretics, heparin, lithium, beta-blockers, anectine = hyperkalemia

Question 19

Potassium and Diuretics

Answer 19

When diuretics are prescribed, the patient’s serum potassium concentration should be checked before initiation of treatment and then at week 1 and week 4 after the initiation of therapy. In patients with chronic hyperkalemia, any use of ACE inhibitors, ARBs, NSAIDs, potassium sparing diuretics, or salt substitutes containing potassium chloride should be reassessed and likely discontinued

Question 20

Hypokalemia Treatment

Answer 20

Oral or IV potassium - 20 moL/hour is standard for IV in severe cases. Oral is usually better for chronic

Question 21

Hyperkalemia Treatment

Answer 21

Symptomatic - ED refer, IV Calcium to stabilize heart cells, lower serum potassium with beta agonists, Insulin/glucose combinations

Chronic - Often occurs in diabetics, kidney patients, heart failure. Discontinue mediations that contribute

Question 22

Sodium Disturbances

Answer 22

Hyponatremia = NA+ < 120
Hypernatremia = NA+ > 145

Question 23

Causes of Hypernatremia

Answer 23

GI Distress, diuresis, water loss, impaired ability to express thirst, no access to water

Diabetes insipidus can cause it as water intake cannot compensate for fluid loss

Question 24

Hypernatremia presentation

Answer 24

major clinical feature of hypernatremia is a central nervous system disturbance that results from dehydration and shrinkage of brain cells.

Agitation, irritability, tremor, spasticity, hyper-reflexia occur at very high levels

Recent history of water loss is significant

Question 25

Types of Hypernatremia

Answer 25

Hypervolemic = excess sodium with low water intake
Hypovolemic = Free water deficit / diarrhea, diuresis, febrile
Euvolemic = central diabetes insipidus,

Question 26

Hypernatremia Treatment

Answer 26

> 155 = ED refer

Fluid resuscitation if hypovolemic hypernatremia
Lowering sodium level must be done slowly (50% fluid correction in 24 hours, rest in 48-72 hours)

Euvolemic Hypernatremia needs desmopressin

Hypervolemic hypernatremia may ned diuretics and hypotonic fluids

Question 27

Hyponatremia Types

Answer 27

Acute = fluid overload, usually in hospitals
Chronic = diuretic therapy
Exercise-associated = increased water intake before/during/after intense exercise

Question 28

Hyponatremia presentation

Answer 28

new-onset confusion, severe headache, seizures, or coma. More subtle signs and symptoms associated with hyponatremia include headache, blurred vision, dizziness, lethargy, weakness, irritability, restlessness, impaired central nervous system function, history of falls, nonspecific gastrointestinal complaints (e.g., anorexia, nausea, vomiting), influenza-like symptoms, cardiac or respiratory distress, dysgeusia, unusual water-drinking behavior, or weight changes.

Question 29

Syndrome of Inappropriate Antidiuretic Hormone

Answer 29

Excess antidiuretic hormone causes the body to retain too much water and leads to low sodium and low serum osmality

Question 30

Causes of Hyponatemia

Answer 30

Many cases are medication related. Best practice to obtain serum values after stating a medication known to cause sodium changes

-carbamazepine, clofibrate, levetiracetam, NSAID, thiazides, SSRIs

Question 31

Exercise associated disturbances Education

Answer 31

Fluid consumption based on thirst
Sodium supplements are not effective for most
Atheletes need evaluation for sodium disturbances