Quiz: Wall-Eyed and Going Nowhere

Test your understanding of this case with 11 questions.

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Case Information

Review the case details while answering questions

PATIENT DEMOGRAPHICS

59-year-old male

PRESENTING COMPLAINT

Referred for ophthalmic assessment following a recent stroke, with reported double vision and abnormal eye movements.

EXAMINATION FINDINGS

Visual Acuity: OD: 6/6. OS: 6/6

Pupils: Equal and reactive, no RAPD

Fundus: Unremarkable bilaterally

INVESTIGATIONS

Primary position demonstrating bilateral exotropia ("wall-eyed" appearance)

Attempted right gaze demonstrating impaired adduction of the adducting eye

Attempted left gaze demonstrating impaired adduction of the adducting eye

Attempted upgaze demonstrating impaired elevation

Attempted downgaze with lids elevated demonstrating impaired depression

Clinical Photography: Demonstrates bilateral exotropia in primary position, impaired adduction bilaterally on horizontal gaze testing, and impaired elevation and depression on vertical gaze testing.

Axial MRI series demonstrating multiple infarcts involving the paramedian midbrain and both medial longitudinal fasciculi

MRI Brain (axial views, multiple slices): Demonstrates multiple infarcts, involving the midbrain vertical gaze centres and both medial longitudinal fasciculi (MLF).

Question 1 of 11

On attempted right and left gaze, the adducting eye fails to adduct in each direction, while the abducting eye moves normally. What does this pattern represent?

Bilateral CN VI palsies affecting the lateral rectus

A voluntary convergence spasm, unrelated to organic pathology

Bilateral internuclear ophthalmoplegia, a specific brainstem sign

Bilateral CN III palsies affecting the medial rectus

Question 2 of 11

Which structure, when affected bilaterally, produces this impaired adduction pattern?

The oculomotor nerve itself, affected peripherally

The posterior commissure, acting alone here

The medial longitudinal fasciculus (MLF), bilaterally

The optic radiations, posterior to the thalamus

Question 3 of 11

In primary position, this patient's eyes are exotropic ("wall-eyed"). What does this additional feature indicate?

It elevates the diagnosis from simple bilateral INO to WEBINO

It confirms the lesion is peripheral, not central, in origin

It indicates a completely separate, unrelated strabismus

It has no diagnostic significance beyond the INO itself

Question 4 of 11

This patient also has impaired upgaze and downgaze. Which structures localise this additional finding?

The vestibular nuclei, located within the medulla itself

The midbrain vertical gaze centres — riMLF and posterior commissure

The abducens nucleus, located within the pons itself

The optic chiasm, situated at the base of the brain

Question 5 of 11

What is the most likely diagnosis?

Ocular myasthenia gravis, affecting all directions of gaze

WEBINO syndrome — bilateral INO, exotropia, and vertical gaze palsy

Progressive supranuclear palsy, a neurodegenerative condition

Isolated bilateral CN VI palsies, from a peripheral process

Question 6 of 11

Why are the bilateral MLF and the midbrain vertical gaze centres affected together in this patient?

This combination only occurs with a single large mass lesion

These paramedian midbrain structures share a common vascular supply

These structures are anatomically fused and always affected together

There is no anatomical relationship between these structures

Question 7 of 11

How does this presentation differ from Parinaud's (dorsal midbrain) syndrome, which also causes impaired vertical gaze?

The two syndromes are clinically identical and cannot be distinguished

This patient also has bilateral INO and exotropia, unlike Parinaud's

Parinaud's syndrome always includes bilateral INO as a core feature

WEBINO syndrome never involves any vertical gaze abnormality

Question 8 of 11

Why is MRI preferred over CT for confirming this diagnosis?

CT and MRI provide identical information in this context

MRI provides superior visualisation of the brainstem and posterior fossa

MRI is preferred solely because it avoids ionising radiation

CT cannot be performed at all in suspected stroke presentations

Question 9 of 11

Given the MRI shows multiple infarcts, what history is important to establish?

History of any recent, significant head trauma

Vascular risk factors — hypertension, hyperlipidaemia, diabetes, AF

Family history of a hereditary optic neuropathy specifically

History of any prior ocular surgery performed previously

Question 10 of 11

What are the general principles of managing this patient going forward?

High-dose oral corticosteroids as the primary treatment

Secondary stroke prevention and vascular risk factor modification

Reassurance only, as multiple infarcts need no further action

Immediate neurosurgical decompression of the affected midbrain

Question 11 of 11

What anatomical extent of injury is required to produce the full WEBINO syndrome, as opposed to isolated bilateral INO alone?

Involvement of the cerebellum alone is required for this syndrome

Involvement of the MLF on only one side is sufficient

Involvement of both MLFs together with the vertical gaze centres

Any single, isolated brainstem lesion produces this full syndrome