A patient has difficulty in smelling. The nurse assesses for which cranial nerve?

Appeared in: NIMHANS Nursing Officer - 2021

Explanation

The question links the symptom of difficulty smelling directly to the function of a specific cranial nerve.
Cranial Nerve I, the Olfactory nerve, is exclusively a sensory nerve dedicated to the sense of smell.
Damage or dysfunction along the olfactory pathway, from the nasal cavity to the temporal lobe, results in altered smell perception.
Therefore, assessing CN I is the correct action for a patient with difficulty smelling.

Option B: CN II is the Optic nerve. Its function is purely sensory, but it is responsible for vision, not smell.
Option C: CN III is the Oculomotor nerve. It is a motor nerve that controls most of the eye's movements, pupil constriction, and eyelid elevation.
Option D: CN IV is the Trochlear nerve. It is a motor nerve that controls the superior oblique muscle, which moves the eye downward and inward.

Clinical Relevance

Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing Cranial Nerve Functions in acute care settings.
Assessing the sense of smell is a fundamental part of a complete neurologic exam. Anosmia can be an early sign of neurodegenerative diseases like Parkinson's or Alzheimer's disease.
Loss of smell has significant safety implications, as the patient may be unable to detect dangers like smoke from a fire, gas leaks, or spoiled food.
Recent events have highlighted that anosmia can be a prominent symptom of viral infections, such as COVID-19, due to damage to olfactory support cells.

How to Approach the Question

First, identify the key symptom presented in the question stem: 'difficulty in smelling'.
Next, recall the primary functions of the 12 cranial nerves, or at least the ones listed in the options.
Match the symptom (smell) to the corresponding cranial nerve. The Olfactory nerve (CN I) is solely responsible for the sense of smell.
Evaluate the other options to confirm they are incorrect. CN II (Optic) is for vision, and CN III (Oculomotor) and CN IV (Trochlear) are for eye movement.
Select the option that correctly links the symptom to the nerve function.

Concept Tested & Keywords

Concept Tested: Cranial Nerve Functions
Stem keywords: difficulty in smelling, cranial nerve
Lead-in keywords: which
Clinical cues: Difficulty in smelling (anosmia/hyposmia) as the primary symptom.

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E6 Nursing Fundamentals Potter Perry 12e Part 3 p. 125-127

E6 Medicine Macleod Clinical Examination 15e p. 148-150

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1358-1360

Practise the full NIMHANS Nursing Officer - 2021

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