Enlarged pupils indicates -

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Explanation

Enlarged pupils, medically known as mydriasis, can be a critical sign of a severe head injury.
An injury leading to increased intracranial pressure (ICP) can compress the oculomotor nerve (Cranial Nerve III).
Since CN III is responsible for pupillary constriction (a parasympathetic function), its impairment results in an unopposed sympathetic action, causing the pupil to dilate.
Direct ocular trauma can also damage the iris sphincter muscle, leading to a dilated pupil.

Option B: Narcotics, specifically opioids, are central nervous system depressants that cause pupillary constriction (miosis), often described as 'pinpoint pupils'.
Option C: Pilocarpine is a cholinergic (parasympathomimetic) drug that acts as a miotic agent, meaning it directly stimulates the muscles that cause the pupil to constrict.
Option D: This option is incorrect because two of the choices, narcotics ingestion and pilocarpine, cause pupillary constriction, which is the opposite of enlarged pupils.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Causes of pupillary dilation (mydriasis) as background academic context rather than a clinical decision trigger.
Pupil assessment (size, equality, and reactivity to light) is a fundamental and rapid component of the neurological examination, especially in emergency and critical care settings.
A sudden change to a unilateral or bilateral dilated, non-reactive pupil is a neurological emergency. It often indicates rising intracranial pressure and requires immediate physician notification and intervention.
What if? - If a patient presented with bilaterally constricted, 'pinpoint' pupils, the nurse's primary suspicion should shift from head injury to opioid overdose (requiring naloxone) or a brainstem (pontine) hemorrhage, prompting a different set of immediate actions.

How to Approach the Question

First, understand the term 'enlarged pupils'. This is medically known as mydriasis.
Recall the basic physiology of pupillary control. The parasympathetic nervous system (via CN III) constricts the pupil, while the sympathetic nervous system dilates it.
Evaluate each option's effect on this system:
Injury (head): Can cause pressure on the parasympathetic nerve (CN III), inhibiting its constricting action and leading to dilation.
Narcotics: Are known to cause central nervous system depression and stimulate parasympathetic effects on the eye, leading to constriction (miosis).
Pilocarpine: Is a parasympathomimetic drug, meaning it mimics the parasympathetic system, causing constriction.

Concept Tested & Keywords

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1728-1730

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