NORCET 3 - 2022 (Shif…: In a patient Tetany like spasm is seen. Which are caused by due to imbalance of which electrolyte?

NORCET 3 - 2022 (Shift-2)

Applied Physiology

Easy

Appeared in: NORCET 3 - 2022 (Shift-2)

Explanation

Tetany is the primary clinical manifestation of hypocalcemia, which is a low level of calcium in the blood (serum calcium below 9.0 mg/dL).
Low calcium levels increase the excitability of nerve and muscle cells. This occurs because calcium ions normally stabilize the cell membrane, making it less permeable to sodium ions.
Without sufficient calcium, sodium channels open more easily, leading to spontaneous and repetitive firing of nerves, which causes involuntary muscle contractions (tetany).
Classic signs of latent tetany in hypocalcemia include Chvostek's sign (facial muscle twitching) and Trousseau's sign (carpopedal spasm).

Option A: Low potassium (hypokalemia) causes hyperpolarization of muscle cells, making them less excitable. This leads to muscle weakness, fatigue, and cardiac arrhythmias, not the hyperexcitability seen in tetany.
Option C: High calcium (hypercalcemia) has the opposite effect of hypocalcemia; it decreases neuromuscular excitability. This results in symptoms like muscle weakness, lethargy, confusion, and constipation.
Option D: Low sodium (hyponatremia) primarily affects the central nervous system by causing cerebral edema. This leads to symptoms like confusion, headache, and seizures. While muscle twitching can occur, tetany is not the characteristic sign.

Clinical Relevance

Nursing practice connection: Use the key finding related to Pathophysiology of Tetany and Electrolyte Imbalances to guide bedside assessment, documentation, and the next nursing action.
A nurse's priority for a patient with tetany is to protect the airway, as laryngospasm is a life-threatening complication of severe hypocalcemia. Emergency airway equipment must be readily available.
Nurses must initiate seizure precautions, continuously monitor the patient's cardiac rhythm for dysrhythmias (prolonged QT interval), and assess for changes in neurological status.
When administering IV calcium, it must be done slowly and with caution, as rapid infusion can cause cardiac arrest. The IV site must be monitored for extravasation, which can cause tissue necrosis.

How to Approach the Question

First, identify the key clinical sign presented in the question stem: 'Tetany like spasm'.
Recall the major functions and hallmark signs of imbalance for the electrolytes listed in the options (Potassium, Calcium, Sodium).
Associate the term 'tetany' with its most common electrolyte cause. Tetany is a classic, textbook sign of hypocalcemia due to increased neuromuscular excitability.
Systematically evaluate the other options to confirm they are incorrect. Hypokalemia and hypercalcemia both cause muscle weakness (decreased excitability), and hyponatremia primarily causes cerebral symptoms.
Select the option that directly links the defining clinical sign (tetany) to the correct electrolyte imbalance.

Concept Tested & Keywords

Concept Tested: Pathophysiology of Tetany and Electrolyte Imbalances
Stem keywords: Tetany, spasm, electrolyte imbalance
Lead-in keywords: caused by
Clinical cues: The presence of 'tetany like spasm' is a classic clinical sign pointing directly to a specific electrolyte disturbance.

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