Electrolyte Imbalances: Potassium, Sodium, Calcium, Magnesium

Electrolytes such as potassium, sodium, calcium, and magnesium are key for muscle and nerve conduction.
Electrolyte imbalances disrupt the body's electrical circuitry, affecting impulse transmission.

NCLEX often includes "select all that apply" questions which require comprehensive knowledge.
Nursing textbooks may not have identical lists of symptoms for electrolyte imbalances.
Memorizing lists is unreliable because NCLEX may use different sources.
Solution: Understand the underlying principles of how electrolytes function in the body rather than memorizing rote lists.

The earliest sign of all electrolyte disorders (hyper/hypokalemia, calcemia, magnesemia, and natremia) is numbness and tingling in the fingers, toes, or lips.
Paresthesia is a medical term for numbness and tingling.
The universal sign of all electrolyte disorders is muscle weakness.
Paresis is a medical term for muscle weakness.
If you see paresthesia or paresis on any electrolyte question, select it.

Kalemia refers to potassium levels in the blood.
Imbalances include hyperkalemia (high potassium) and hypokalemia (low potassium).
Rule: "Kalemias do the same as the prefix, except for heart rate and urine output."

Hyperkalemia means high potassium levels.
The prefix "hyper" indicates an increase in most bodily functions.
With hyperkalemia, draw an arrow up to signify the increase.
Exceptions: Heart rate and urine output decrease.
Example: If a patient has hyperkalemia, expect:
- Bradycardia (low heart rate)
- Seizures (increased activity)
- Plus four reflexes (hyperreflexia)
- Avoid lethargy and constipation in this instance, as these are indicators of decreased activity.

Hypokalemia means low potassium levels.
The prefix "hypo" indicates a decrease in most bodily functions.
With hypokalemia, draw an arrow down to signify the decrease.
Exceptions: Heart rate and urine output increase.
Expect:
- Tachycardia (high heart rate)
- Polyuria (high urine output)
- Slow respirations, semi-comatose state, difficult to arouse, hyporeflexia, paralytic ileus, constipation, and urinary retention are also expected.

Hypocalcemia means low calcium levels.
Since calcemias do the opposite of the prefix, draw an arrow up.
Expect increased bodily functions and consider any blood pressure issues.
Expect tachycardia, tachypnea, agitation, hyperreflexia, irritability, diarrhea, and borborygmy.
Two signs of neuromuscular irritability associated with low calcium:
- Chavostek's sign: Tapping the cheek near the ear causes facial muscle spasm.
- Trousseau's sign: Inflating a blood pressure cuff on the arm induces a carpal spasm.

Rule: "Magnesemias do the opposite of the prefix and anything to blood pressure."

Hypermagnesemia means high magnesium levels.
Since magnesemias do the opposite of the prefix, draw an arrow down, and consider blood pressure issues.

Hypomagnesemia means low magnesium levels.
Since magnesemias do the opposite of the prefix, draw an arrow up, and consider blood pressure issues.

Calcemias and magnesemias do the opposite of the prefix, and anything to blood pressure.

If you're unsure between two electrolyte disorders, and one of them is magnesium, avoid picking magnesium because it's a minor player.
If choosing between calcium and potassium, and the symptom relates to skeletal muscle or nerve function, choose calcium.