Electrolytes and Electrolyte Imbalances

Introduction to Electrolytes and Imbalances

• This video covers key electrolytes: Sodium, Calcium, Potassium, and Magnesium.

• Important for Medical-Surgical, Fundamentals, and Nutrition nursing courses.

Sodium (Na+)

• Function: Instrumental for maintaining fluid balance in the body and for nerve and muscle function.

• Normal Range: Between $136$ and $145$ mEq/L. (Note: Ranges may slightly vary by source, focus on numbers that are significantly out of range on exams).

Hypernatremia

• Definition: Sodium level above $145$ mEq/L.

• Causes:

  • Excess sodium intake.

  • Disorders such as Cushing's syndrome or diabetes insipidus.

• Signs and Symptoms:

  • Thirst.

  • Agitation.

  • Muscle weakness.

  • GI upset.

• Treatment:

  • Provide hypotonic IV fluids, e.g., $0.45\%$ NaCl.

  • Key Point: Correct sodium balance slowly to avoid cerebral edema or seizures. Do not quickly increase or decrease the sodium level.

  • Diuretics (e.g., furosemide) to promote sodium loss.

  • Restrict the patient's intake of sodium.

  • Increase the patient's intake of water.

Hyponatremia

• Definition: Sodium level below $136$ mEq/L.

• Possible Causes:

  • Diuretics.

  • Kidney failure.

  • Diaphoresis.

  • Syndrome of Inappropriate Antidiuretic Hormone (SIADH).

  • Hypoglycemia.

  • Heart failure.

• Signs and Symptoms:

  • Confusion: Very common, especially in the elderly. New-onset confusion in older patients often warrants checking electrolyte levels (e.g., hyponatremia) or for a Urinary Tract Infection (UTI).

  • Fatigue.

  • Nausea and vomiting.

  • Headache.

• Treatment:

  • Provide hypertonic IV fluid replacement, e.g., $2-3\%$ NaCl.

  • Key Point: Correct sodium level slowly.

  • Encourage increased sodium intake.

  • Restrict the patient's fluid intake.

Calcium (Ca2+)

• Function: Important for bone and teeth formation, nerve and muscle function, and blood clotting.

• Normal Range: Between $9$ and $10.5$ mg/dL.

• Mnemonics:

  • CA (Calcium) -> California: Anticipate a major earthquake between $9$ and $10.5$ on the Richter scale.

  • Call 911: Helps remember levels should be roughly between $9$ and $11$ (allowing for slight variation).

Hypercalcemia

• Definition: Calcium level above $10.5$ mg/dL.

• Causes:

  • Hyperparathyroidism (parathyroid gland regulates calcium; dysfunction leads to excess).

  • Corticosteroids.

  • Bone cancer.

• Signs and Symptoms:

  • Constipation.

  • Decreased deep tendon reflexes.

  • Kidney stones.

  • Lethargy.

  • Weakness.

• Treatment:

  • Provide $0.9\%$ IV fluids (isotonic saline, e.g., $0.9\%$ NaCl).

  • Calcitonin (tones down calcium in the bloodstream).

  • Dialysis for severe hypercalcemia.

Hypocalcemia

• Definition: Calcium level under $9$ mg/dL.

• Causes:

  • Diarrhea.

  • Vitamin D deficiency (Vitamin D is essential for calcium absorption).

  • Hypoparathyroidism (under-functioning parathyroid gland).

  • Accidental damage to the parathyroid gland during thyroidectomy.

• Signs and Symptoms:

  • Positive Chvostek Sign: Tapping the patient's cheek causes it to twitch (Chvostek / Cheek).

  • Positive Trousseau Sign: Inflating a blood pressure cuff on the arm causes carpal spasm (contraction of hand and fingers).

  • Muscle spasms.

  • Numbness and tingling in the lips and fingers.

  • GI upset.

• Treatment:

  • Calcium supplements (oral or IV).

  • Encourage increased intake of calcium-rich foods.

Potassium (K+)

• Function: Important for maintaining intracellular fluid (ICF) and in nerve and muscle function.

• Normal Range: Between $3.5$ and $5.0$ mEq/L.

• Mnemonics:

  • 5K Race: Running a $5 ext{K}$ is roughly $3.2$ miles. (Note: Speaker says 3.2, but standard range is 3.5, important to clarify).

  • Bananas: Buy bananas in a bunch of $3$ to $5$ (also reminds that bananas are potassium-rich).

Hyperkalemia

• Definition: Potassium level above $5.0$ mEq/L.

• Causes:

  • Diabetic Ketoacidosis (DKA).

  • Metabolic Acidosis.

  • Key Connection: DKA, metabolic acidosis, and hyperkalemia often occur together.

  • Salt substitutes (many contain potassium).

  • Kidney failure.

• Signs and Symptoms:

  • Dysrhythmias: This is a key and dangerous complication for both hyperkalemia and hypokalemia. Close monitoring of potassium levels is crucial.

  • Muscle weakness.

  • Numbness and tingling.

  • Nausea and vomiting.

• Treatment:

  • Furosemide (diuretic that promotes potassium loss; helpful here, though usually a side effect).

  • Kayexalate (sodium polystyrene sulfonate).

  • Insulin: Helps move potassium from extracellular fluid (ECF) into intracellular fluid (ICF).

    • Important: Insulin also moves glucose into the ICF, risking hypoglycemia. Therefore, give dextrose concurrently with insulin to prevent hypoglycemia.

  • Encourage decreased intake of potassium-rich foods (e.g., bananas, potatoes, cantaloupe).

Hypokalemia

• Definition: Potassium level under $3.5$ mEq/L.

• Causes:

  • Diuretics (e.g., furosemide, a known side effect).

  • GI losses (e.g., vomiting, NG tube suctioning).

  • Diaphoresis.

  • Cushing's syndrome.

  • Metabolic alkalosis.

• Signs and Symptoms:

  • Dysrhythmias: Again, a key concern.

  • Muscle spasming or weakness.

  • Constipation or an ileus (paralysis of GI peristalsis).

• Treatment:

  • Potassium supplements (oral, available as large pills or mixed powder with juice, often unpleasant taste).

  • Intravenous (IV) potassium administration.

    • Important: IV potassium can cause phlebitis (inflammation of the vein) and pain. Request doctors to order potassium mixed with lidocaine to reduce pain.

  • Encourage increased intake of potassium-rich foods (e.g., bananas, potatoes, cantaloupe).

Magnesium (Mg2+)

• Function: Important for many biochemical reactions in the body and for muscle and nerve function.

• Normal Range: Between $1.3$ and $2.1$ mg/dL.

• Mnemonic:

  • MG Car: Small British car, only fits $1$ or $2$ people, helping remember the range is roughly between $1$ and $2$.

Hypermagnesemia

• Definition: Magnesium level above $2.1$ mg/dL.

• Causes:

  • Kidney disease.

  • Excess intake of antacids or laxatives containing magnesium.

• Signs and Symptoms: (Often, when magnesium is too high, things go "low")

  • Hypotension.

  • Lethargy.

  • Muscle weakness.

  • Decreased deep tendon reflexes.

  • Respiratory and cardiac arrest.

• Treatment:

  • Furosemide to help decrease magnesium levels.

  • Calcium administration to reverse cardiac effects of excessive magnesium.

Hypomagnesemia

• Definition: Magnesium level below $1.3$ mg/dL.

• Causes:

  • GI losses.

  • Diuretics.

  • Malnutrition.

  • Alcohol abuse: Patients with alcohol abuse disorder often have very low magnesium levels and require supplements.

• Signs and Symptoms: (Often, when magnesium is too low, things "increase" or are hyper-)

  • Dysrhythmia, including Torsades de pointes.

  • Tachycardia.

  • Hypertension.

  • Increased deep tendon reflexes.

  • Tremors.

  • Seizures.

• Treatment:

  • Magnesium supplements (oral or IV).

  • Encourage increased intake of magnesium-rich foods.

Knowledge Check (Quiz)

• Question 1: A positive Chvostek's and Trousseau's sign are indicative of what electrolyte imbalance?

  • Answer: Hypocalcemia.

• Question 2: What key side effect is caused by hyperkalemia and hypokalemia?

  • Answer: Dysrhythmia.

• Question 3: Signs and symptoms of hypomagnesemia include hypotension and decreased deep tendon reflexes, true or false?

  • Answer: False. With hypomagnesemia, you would observe increased deep tendon reflexes and hypertension.