NORCET 2 -2021 (Shift…: During RTA, a person has a stroke, then his pupils are?

NORCET 2 -2021 (Shift-2)

Medical & Surgical Nursing

Hard

Appeared in: NORCET 2 -2021 (Shift-2)

Explanation

Unequal pupils, or anisocoria, is a critical sign of rising intracranial pressure (ICP), especially after trauma.
A stroke following an RTA often involves a bleed (hemorrhage) that creates a mass effect on one side of the brain.
This mass can cause herniation and compress the oculomotor nerve (CN III) on the same side as the injury.
Compression of CN III leads to paralysis of the pupillary constrictor muscles, causing the pupil on that side to dilate while the other remains normal, resulting in an unequal appearance.

Option A: Pupils becoming fixed (and typically dilated) is a very late and grave sign of severe, often irreversible, brainstem damage or brain death. Unequal pupils are an earlier warning sign of a developing mass lesion.
Option C: Bilaterally constricted or 'pinpoint' pupils are not characteristic of a unilateral cerebral stroke. This finding points towards a different pathology.
Option D: While one pupil does dilate, this option usually implies bilateral dilation. Symmetrically dilated and non-reactive pupils are a sign of severe brain anoxia or brain death, which is a later stage of injury.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Neurological Assessment and Pupillary Changes in Traumatic Brain Injury as background academic context rather than a clinical decision trigger.
A change in pupil size, equality, or reactivity is a neurological emergency. Nurses must perform and document pupillary checks frequently in patients with head injuries as part of the Glasgow Coma Scale (GCS).
Any new onset of anisocoria must be reported to the physician immediately, as it may signal a life-threatening increase in ICP requiring urgent intervention (e.g., osmotic therapy, surgical decompression).
What if? If both pupils were constricted and non-reactive ('pinpoint'), the primary suspicion would shift from a large cerebral stroke to a pontine hemorrhage or opioid overdose, prompting different diagnostic and treatment priorities (e.g., naloxone administration for opioid overdose).

How to Approach the Question

First, identify the key elements in the question: 'RTA' (trauma), 'stroke' (acute brain injury), and 'pupils' (neurological sign).
Connect the pathophysiology: An RTA can cause a traumatic brain injury, such as a bleed (hemorrhagic stroke). A bleed is a unilateral (one-sided) mass.
Consider the effect of a unilateral mass: A mass on one side of the brain increases pressure and can compress nearby structures. The oculomotor nerve (CN III), which controls the pupil, is highly susceptible to this compression.
Predict the outcome: Compression of CN III on one side will cause that pupil to dilate. The other pupil, controlled by the unaffected nerve, will remain normal. This creates an 'unequal' state.
Evaluate the options based on this prediction. 'Unequal' is the only option that describes this classic unilateral neurological sign. The other options describe bilateral or different conditions.

Concept Tested & Keywords

Concept Tested: Neurological Assessment and Pupillary Changes in Traumatic Brain Injury
Stem keywords: RTA, stroke, pupils
Lead-in keywords: are?
Clinical cues: The combination of RTA (trauma) and stroke (brain injury) points towards a traumatic brain injury with a possible intracranial bleed.
Negative lead-in flag: false

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E6 Medicine Harrison 22e Part 1 p. 231-233

E6 Medicine Macleod Clinical Examination 15e p. 187-189