A patient on hemodialysis develops muscle weakness and muscle cramps during the procedure. Which electrolyte imbalance is most likely responsible?

Appeared in: NORCET 10 Mains

Explanation

Hypocalcemia, or a low serum calcium level, is the correct answer.
During hemodialysis, calcium can be rapidly removed from the blood, leading to an acute drop in serum levels.
Low extracellular calcium increases the permeability of nerve cell membranes to sodium, making them hyperexcitable.
This increased neuromuscular excitability manifests as muscle twitching, spasms, and painful cramps, which are classic symptoms of hypocalcemia.

Option A: Hypercalcemia (high calcium) decreases neuromuscular excitability, leading to muscle weakness, fatigue, and diminished reflexes, not cramps.
Option B: While hypomagnesemia can also cause muscle cramps and tetany, acute cramps developing during a hemodialysis session are more classically and frequently attributed to the rapid shifts in calcium.
Option D: Hyperkalemia (high potassium) typically causes significant muscle weakness that can progress to paralysis, along with life-threatening cardiac dysrhythmias. It does not cause the characteristic tetany-like muscle cramps.

Clinical Relevance

Nursing practice connection: Use the key finding related to Electrolyte imbalances as a complication of hemodialysis to guide bedside assessment, documentation, and the next nursing action.
Nurses must monitor patients on hemodialysis closely for signs of hypocalcemia, including cramping, numbness, and tingling around the mouth or in the extremities.
Assessment for Chvostek's and Trousseau's signs is a key nursing skill to detect latent tetany from hypocalcemia.
Patient safety is critical. If severe hypocalcemia is suspected, initiate seizure precautions and prepare for potential IV calcium administration as ordered.

How to Approach the Question

First, identify the core elements of the clinical scenario: a patient undergoing hemodialysis.
Next, pinpoint the key symptoms presented: muscle weakness and, crucially, muscle cramps.
Recall the common acute complications associated with the hemodialysis procedure, particularly electrolyte shifts.
Evaluate each option by comparing its classic neuromuscular signs to the patient's symptoms.
Hypercalcemia and hyperkalemia primarily cause weakness/flaccidity, which makes them less likely.
Both hypocalcemia and hypomagnesemia can cause cramps. However, rapid calcium removal is a very common and direct consequence of dialysis, making hypocalcemia the 'most likely' cause for acute cramps during the procedure.

Concept Tested & Keywords

Concept Tested: Electrolyte imbalances as a complication of hemodialysis.
Stem keywords: hemodialysis, muscle weakness, muscle cramps
Lead-in keywords: most likely
Clinical cues: The timing of symptoms ('during the procedure') is a key clue, pointing to an acute change caused by the dialysis treatment itself.

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E6 Nursing Fundamentals Taylor p. 779-781

E6 Nursing Brunner Adult Health 3SA Vol 1 Part 1 p. 155-157

E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 52-54

Practise the full NORCET 10 Mains

Attempt every question from this paper in a timed mock, then review the full solution for each one.