& x20;A patient has sudden, painful loss of vision with RAPD but a normal-appearing optic disc on fundoscopy.… - INI-CET EXAM -2026

INI-CET EXAM -2026

Medical & Surgical Nursing

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Appeared in: INI-CET EXAM -2026

Explanation

Retrobulbar neuritis is an inflammation of the optic nerve occurring behind the optic nerve head.
Because the inflammation is posterior to the visible part of the nerve (the optic disc), the funduscopic exam is initially normal.
Pain, especially with eye movements, is a hallmark symptom due to the inflammation of the nerve sheath, which is tethered to the extraocular muscles.
The presence of a Relative Afferent Pupillary Defect (RAPD) confirms the dysfunction of the afferent pathway of the pupillary light reflex, localizing the lesion to the optic nerve.

Option A: AION (Anterior Ischemic Optic Neuropathy) presents with a swollen and pale optic disc on fundoscopy, not a normal-appearing one. Also, the vision loss in AION is typically painless.
Option B: Central retinal artery occlusion (CRAO) causes sudden, profound, and painless vision loss. The characteristic fundoscopic finding is a pale retina with a 'cherry-red spot' at the macula, not a normal optic disc.
Option D: Papilledema is, by definition, swelling of the optic disc due to increased intracranial pressure. This contradicts the finding of a 'normal-appearing optic disc'. It is also typically bilateral and does not cause pain with eye movements.

Clinical Relevance

Nursing practice connection: Use the key finding related to Differential diagnosis of acute vision loss to guide bedside assessment, documentation, and the next nursing action.
Retrobulbar neuritis is the presenting symptom in approximately 20-25% of individuals with Multiple Sclerosis (MS).
A nurse should be aware that a young adult, especially a female, presenting with acute retrobulbar neuritis requires a prompt referral for a neurological evaluation to rule out MS.
Patient education should include explaining the importance of follow-up and reporting any new neurological symptoms like numbness, tingling, weakness, or balance problems.

How to Approach the Question

First, break down the clinical presentation into key findings: 1) Sudden vision loss, 2) Pain with eye movement, 3) Presence of RAPD, and 4) Normal fundus exam.
The presence of pain immediately makes inflammatory conditions like neuritis more likely than purely vascular events like AION or CRAO, which are typically painless.
The finding of a 'normal-appearing optic disc' is the most crucial clue. This rules out conditions that, by definition, involve visible changes to the optic disc or retina.
Evaluate each option against the 'normal disc' finding: AION (swollen disc), CRAO (cherry-red spot), and Papilledema (swollen disc) are all inconsistent.
The only option consistent with a normal fundus exam in the setting of acute optic neuropathy is Retrobulbar Neuritis, where the inflammation is behind the visible nerve head.
Confirm the diagnosis by matching the remaining signs (pain, RAPD) which are classic for optic neuritis.

Concept Tested & Keywords

Concept Tested: Differential diagnosis of acute vision loss
Stem keywords: sudden, painful loss of vision, RAPD, normal-appearing optic disc, fundoscopy
Lead-in keywords: What is the diagnosis
Clinical cues: The combination of painful vision loss and a normal fundus exam is a key clinical clue pointing towards a retrobulbar process.

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E6 Medicine Harrison 22e Part 1 p. 268-270

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 1324-1326