The nurse is caring for a client with an intracranial aneurysm. The nurse interprets that which of the following is related to the dysfunction of cranial nerve III?

1. A

   Mild drowsiness

2. B

   Ptosis of the left eyelid

3. C

   Slight slurring of speech

4. D

   Less frequent spontaneous speech

Appeared in: DHS 2018 shift 1st

Explanation

• The oculomotor nerve (Cranial Nerve III) provides motor function to the levator palpebrae superioris muscle, which elevates the upper eyelid.
• Ptosis, or drooping of the eyelid, is a direct result of the weakness or paralysis of this muscle due to nerve damage.
• An expanding intracranial aneurysm, particularly from the posterior communicating artery, can directly compress CN III, causing signs like ptosis.
• This makes ptosis a specific and localizing sign of CN III palsy.

Why Other Options Were Wrong

• Option A: Mild drowsiness is a sign of altered level of consciousness, not a focal sign of CN III dysfunction. It typically indicates increased intracranial pressure (ICP) affecting the brainstem or cerebral cortex.
• Option C: Slurred speech (dysarthria) relates to the motor control of articulation, which is governed by other cranial nerves, primarily the glossopharyngeal (IX), vagus (X), and hypoglossal (XII) nerves.
• Option D: Less frequent spontaneous speech suggests expressive aphasia, a language processing disorder. This function is located in Broca's area in the frontal lobe of the cerebrum, not controlled by a cranial nerve.

Related Visual

Clinical Relevance

• Nursing practice connection: Use the key finding related to Assessment of Cranial Nerve III (Oculomotor) Dysfunction to guide bedside assessment, documentation, and the next nursing action.
• For a patient with a known or suspected intracranial aneurysm, the onset of ptosis is a neurological emergency. It can signal that the aneurysm is expanding, leaking, or putting critical pressure on brain structures.
• Nurses must perform frequent and precise neurological assessments, including cranial nerve checks, for these patients. Any new deficit, especially in CN III, must be reported to the physician immediately.
• What if? If the patient developed a unilateral facial droop involving the forehead and mouth, the nurse would suspect dysfunction of the Facial Nerve (CN VII), which could be caused by a different lesion or pathology, not typically a posterior circulation aneurysm.

How to Approach the Question

• First, identify the core of the question: it's asking for a specific sign of Cranial Nerve III dysfunction.
• Recall the primary functions of CN III: eyelid elevation (levator palpebrae), most eye movements, and pupillary constriction.
• Evaluate each option against the known functions of CN III.
• Option A (drowsiness) relates to consciousness, not a specific cranial nerve.
• Option B (ptosis) directly relates to the eyelid elevation function of CN III.
• Option C (slurred speech) relates to articulation, controlled by other nerves (IX, X, XII).

Concept Tested & Keywords

• Concept Tested: Assessment of Cranial Nerve III (Oculomotor) Dysfunction
• Stem keywords: intracranial aneurysm, cranial nerve III, dysfunction
• Lead-in keywords: related to
• Clinical cues: The patient's diagnosis of an intracranial aneurysm is a key cue, as aneurysms are a common cause of cranial nerve compression.

Question ID

QzSOKUtO4pZrlS-iPdKAz2

Copy ID

Reference Book

E6 Medicine Harrison 22e Part 1 pp. 275-277, 276-278

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1359-1361