Quiz: One Eye Up, One Eye Down

Test your understanding of this case with 10 questions.

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Case Information

Review the case details while answering questions

PATIENT DEMOGRAPHICS

79-year-old male

PRESENTING COMPLAINT

Sudden onset of vertical diplopia.

EXAMINATION FINDINGS

Visual Acuity: OD: 6/24 (longstanding cataract). OS: 6/9

Pupils: Bilateral miosis, poorly reactive to light, with intact constriction on convergence (light-near dissociation)

Fundus: Lids: bilateral ptosis, right greater than left

INVESTIGATIONS

Frontal facial photograph demonstrating bilateral ptosis, right greater than left

Lids manually elevated, demonstrating the dense right cataract and ocular alignment

Fixation testing of ocular alignment and motility

Fixation testing with lids elevated, assessing vertical alignment

Further fixation testing of ocular alignment

Fixation testing demonstrating vertical ocular misalignment

Clinical Photography: Demonstrates bilateral ptosis (right greater than left), a dense right cataract, and testing of ocular alignment and motility using a fixation target.

Axial neuroimaging demonstrating an upper midbrain lesion consistent with a metastatic deposit

Neuroimaging (axial view): Demonstrates a lesion in the upper midbrain, consistent with a metastatic deposit.

Question 1 of 10

The right eye shows a dense, longstanding-appearing cataract with reduced visual acuity. How should this finding be interpreted alongside the acute presentation?

As a sign of critically elevated intracranial pressure

As direct evidence the tumour has invaded the right globe

As an incidental finding, unrelated to the acute presentation

As the primary cause of this patient's vertical diplopia

Question 2 of 10

Given the likely diagnosis, what additional history is essential to establish?

History of migraine with visual aura in early adulthood

Any known history of malignancy or symptoms of an occult primary

History of any previous refractive surgery performed

Family history of glaucoma in first-degree relatives

Question 3 of 10

Sudden vertical diplopia in a 79-year-old is often due to a benign, microvascular CN IV palsy. Which features here should prompt urgent imaging rather than watchful waiting?

The finding of a pre-existing cataract in the right eye

The patient's age alone, since all diplopia over 70 needs imaging

The additional bilateral ptosis, miosis, and impaired vertical gaze

The presence of any refractive error in either eye

Question 4 of 10

What distinguishes skew deviation from a single cranial nerve palsy as a cause of vertical diplopia?

Skew deviation is always accompanied by a fixed, dilated pupil

Skew deviation reflects a supranuclear imbalance, not a single palsy

Skew deviation only ever affects horizontal, not vertical, alignment

Skew deviation resolves spontaneously within 24 hours in all cases

Question 5 of 10

Alongside light-near dissociation, this patient has bilateral miosis. What does this additional finding reflect?

The expected effect of long-term topical glaucoma eye drops

A sign that specifically excludes a midbrain localisation entirely

A separate, coincidental finding of bilateral Horner's syndrome

A recognised additional pupillary feature of dorsal midbrain lesions

Question 6 of 10

What is the most likely diagnosis?

Progressive supranuclear palsy, a neurodegenerative disorder

Parinaud's syndrome, from a metastatic tumour to the upper midbrain

Ocular myasthenia gravis affecting eyelid and motility function

Bilateral CN III palsies, from microvascular ischaemic disease

Question 7 of 10

Which structure, when affected by an upper midbrain lesion, is responsible for the impaired vertical gaze seen in this syndrome?

The vestibular nuclei, located within the medulla

The oculomotor nucleus alone, without any other structures

The rostral interstitial nucleus of the MLF and posterior commissure

The abducens nucleus, located within the pons itself

Question 8 of 10

Beyond brain imaging, what further investigation is appropriate given a newly identified brain metastasis with no known primary?

Staging CT (chest, abdomen, pelvis) to search for a primary

Genetic testing specifically for hereditary retinoblastoma

Repeat brain imaging alone in three months' time

Formal visual field testing as the priority investigation

Question 9 of 10

What are the general principles of managing a newly identified brain metastasis in this context?

Immediate curative surgical resection in all cases, regardless of primary

Observation alone, since brain metastases typically resolve spontaneously

Topical treatment directed specifically at the ocular findings only

Multidisciplinary oncology input, radiotherapy, and a guarded prognosis

Question 10 of 10

This patient's dorsal midbrain syndrome presents with vertical diplopia, while another patient with the same anatomical syndrome might present with headache and reduced consciousness from hydrocephalus. What does this illustrate?

Vertical diplopia always indicates a more advanced disease stage

The same syndrome can present differently depending on the lesion

Hydrocephalus is a required feature of any dorsal midbrain lesion

These presentations cannot both represent dorsal midbrain syndrome