Neuro-ophthalmic Manifestations of Intracranial Lesions — MCQs

10 questions

Which of the following is NOT typically seen in 3rd nerve palsy?

A female presents with loss of vision in the right halves of both eyes. Where is the lesion located in the optic pathway?

An otherwise healthy 32-year-old woman comes to the physician because of severe headaches and visual disturbances. Physical examination shows papilledema. Which of the following medications is most likely implicated in the development of the suspected diagnosis in this patient?

A 10 year old child presented with headache, vomiting, gait instability and diplopia. On examination he had papilledema and gait ataxia. The most probable diagnosis is –

What is not a feature of raised ICP

Which of the following conditions is MOST commonly associated with an afferent pupillary defect in clinical practice?

Isolated painful third nerve palsy is a feature of aneurysms of:

A 27-year-old female patient presents with sudden diminishing vision associated with a relative afferent pupillary defect in the right eye. On examination, the left eye is normal. Which of the following combinations of investigations would be most appropriate?

Foster Kennedy syndrome is

Q10

Early fundoscopic sign in papilloedema is

Neuro-ophthalmic Manifestations of Intracranial Lesions Indian Medical PG Practice Questions and MCQs

Question 1: Which of the following is NOT typically seen in 3rd nerve palsy?

A. Mydriasis
B. Ptosis
C. Loss of abduction (Correct Answer)
D. Loss of light reflex

Explanation: ***Loss of abduction*** - The **oculomotor nerve (CN III)** controls adduction, elevation, and depression of the eye, but **not abduction**. [2] - **Abduction** is primarily controlled by the **abducens nerve (CN VI)**, so its loss would indicate a CN VI palsy. *Mydriasis* - The **oculomotor nerve (CN III)** innervates the **parasympathetic fibers** to the pupillary constrictor muscles. [3] - Palsy of these fibers leads to unopposed action of the sympathetic dilator muscles, causing **mydriasis (pupil dilation)**. [4] *Ptosis* - The **oculomotor nerve (CN III)** innervates the **levator palpebrae superioris muscle**, which lifts the eyelid. - Dysfunction of this nerve leads to **ptosis (drooping of the eyelid)**. [1] *Loss of light reflex* - The **efferent pathway** for the **pupillary light reflex** travels via the **oculomotor nerve (CN III)** to constrict the pupil. [3] - A 3rd nerve palsy, particularly affecting the parasympathetic fibers, **impairs pupillary constriction**, resulting in a loss of the direct and consensual light reflex in the affected eye. [4]

Question 2: A female presents with loss of vision in the right halves of both eyes. Where is the lesion located in the optic pathway?

A. Left optic tract (Correct Answer)
B. Optic radiation
C. Optic chiasma
D. Right optic tract

Explanation: Left optic tract - A lesion in the **left optic tract** causes **right homonymous hemianopsia**, meaning loss of vision in the right halves of both eyes [1]. - This is because the left optic tract carries visual information from the **nasal retina of the right eye** and the **temporal retina of the left eye**, both of which process the right visual field [1]. *Optic radiation* - A lesion in the optic radiation would also cause a **homonymous hemianopsia** but depending on the specific location within the radiation, it could result in a **quadrantanopia** (loss of a quarter visual field) rather than a complete hemianopsia. - The optic radiation projects from the **lateral geniculate nucleus** to the **visual cortex**, and damage here affects the post-chiasmatic visual pathway [1]. *Optic chiasma* - A lesion at the **optic chiasma** typically results in **bitemporal hemianopsia**, which is the loss of vision in the **temporal halves of both eyes** [1]. - This occurs because the **crossing nasal fibers** from both eyes, which carry information from the temporal visual fields, are affected [1]. *Right optic tract* - A lesion in the **right optic tract** would result in **left homonymous hemianopsia**, meaning loss of vision in the **left halves of both eyes** [1]. - This is due to the right optic tract carrying fibers from the **nasal retina of the left eye** and the **temporal retina of the right eye**, both of which process the left visual field [1].

Question 3: An otherwise healthy 32-year-old woman comes to the physician because of severe headaches and visual disturbances. Physical examination shows papilledema. Which of the following medications is most likely implicated in the development of the suspected diagnosis in this patient?

A. Doxycycline
B. Oral contraceptive pill (Correct Answer)
C. All-trans retinoic acid
D. Lithium

Explanation: ***Oral contraceptive pill*** - **Oral contraceptive pills** are a common risk factor for **idiopathic intracranial hypertension (IIH)**, especially in young, obese women. - IIH presents with symptoms like **severe headaches**, **visual disturbances**, and **papilledema** due to increased intracranial pressure. *Doxycycline* - **Tetracycline antibiotics**, including doxycycline, can induce **IIH** as a side effect. - However, the patient is described as "otherwise healthy" and there is no indication of an infection for which doxycycline would be prescribed. *All-trans retinoic acid* - **Retinoids** like all-trans retinoic acid (ATRA) are a known cause of **IIH**, particularly when used for leukemia or severe acne treatment. - The patient, however, is an "otherwise healthy" 32-year-old woman, making ATRA use less likely in the absence of relevant conditions. *Lithium* - **Lithium** can cause various neurological side effects and rarely has been linked to cases of **IIH**. - This patient has no history of psychiatric illness, making lithium exposure unlikely.

Question 4: A 10 year old child presented with headache, vomiting, gait instability and diplopia. On examination he had papilledema and gait ataxia. The most probable diagnosis is –

A. Suprasellar tumour
B. Hydrocephalus
C. Brain stem tumour
D. Midline posterior fossa tumour (Correct Answer)

Explanation: ***Midline posterior fossa tumour*** - The combination of **headache, vomiting, papilledema (signs of increased intracranial pressure)**, **gait instability, and ataxia** strongly suggests a **midline posterior fossa tumor** in a child. These tumors often obstruct CSF flow, leading to hydrocephalus and cerebellar symptoms. - Common tumors in this location in children include **medulloblastoma** and **pilocytic astrocytoma**, which frequently present with these symptoms due to their proximity to the **fourth ventricle** and **cerebellum**. *Suprasellar tumour* - **Suprasellar tumors** typically present with **visual field deficits** (e.g., bitemporal hemianopia) due to compression of the optic chiasm, and/or **endocrine dysfunction** (e.g., growth delay, diabetes insipidus). - While they can cause hydrocephalus and increased intracranial pressure if large, the prominent **gait instability and ataxia** point away from a primary suprasellar lesion as the most likely cause. *Hydrocephalus* - **Hydrocephalus** itself explains the **increased intracranial pressure (headache, vomiting, papilledema)** and sometimes **gait instability (ataxia)**. - However, hydrocephalus is usually a *consequence* of an underlying obstruction, and in a child presenting acutely with cerebellar dysfunction, a **tumor blocking CSF flow in the posterior fossa** is the most probable underlying cause, not hydrocephalus as the primary diagnosis. *Brain stem tumour* - **Brain stem tumors** typically cause **cranial nerve deficits** (e.g., facial weakness, dysphagia), **long tract signs (hemiparesis)**, and often **multiple types of ataxia**, alongside signs of increased intracranial pressure if they obstruct CSF flow. - While gait instability and diplopia can occur, the overall picture of prominent **gait ataxia** and papilledema without other focal cranial nerve signs makes a primary midline posterior fossa tumor compressing the cerebellum and fourth ventricle more likely.

Question 5: What is not a feature of raised ICP

A. Vomiting
B. Tachycardia (Correct Answer)
C. Blurring of vision
D. Hypertension

Explanation: ***Tachycardia*** - **Bradycardia**, not tachycardia, is a classic component of the **Cushing's triad**, which is a physiological response to increased ICP. - The elevated ICP triggers a reflex arc that causes a decrease in heart rate as the body attempts to maintain cerebral perfusion. *Vomiting* - **Vomiting**, especially projectile and without nausea, is a common symptom of increased ICP due to activation of the **chemoreceptor trigger zone** in the medulla. - The pressure directly stimulates this area, leading to emesis. *Blurring of vision* - **Blurring of vision** is a frequent symptom of raised ICP, often associated with **papilledema** (swelling of the optic disc). - The elevated pressure is transmitted to the optic nerve sheath, impeding venous return and causing nerve swelling. *Hypertension* - **Hypertension** is part of the **Cushing's triad** in response to increased ICP, where the body raises systemic blood pressure to overcome resistance and maintain cerebral blood flow [2]. - This is a compensatory mechanism to ensure adequate perfusion to the brain [1].

Question 6: Which of the following conditions is MOST commonly associated with an afferent pupillary defect in clinical practice?

A. Optic neuritis (Correct Answer)
B. Retinal detachment
C. Cranial nerve palsy
D. Ischemic optic neuropathy

Explanation: ***Optic neuritis*** - An **afferent pupillary defect** (APD), also known as a **Marcus Gunn pupil**, is a hallmark finding in **optic neuritis**, one of the most common causes of APD in clinical practice. - In optic neuritis, inflammation damages the optic nerve, impairing transmission of afferent signals from the retina to the brainstem, leading to a diminished direct pupillary response in the affected eye with a normal consensual response. - **Classic presentation**: Acute unilateral vision loss with pain on eye movement, especially common in young adults and associated with multiple sclerosis. *Retinal detachment* - While extensive retinal detachment can theoretically cause APD if there is severe, widespread retinal dysfunction, this is **uncommon in typical cases**. - Most retinal detachments present with visual field defects and floaters but do **not** reliably produce APD unless nearly complete. - The primary pathology is separation of neurosensory retina from RPE, not direct optic nerve involvement. *Cranial nerve palsy* - Cranial nerve palsies (particularly **CN III**) cause pupillary abnormalities from **efferent pathway dysfunction**, not afferent. - These result in dilated, poorly reactive pupils but do **not** cause an afferent pupillary defect. - APD requires pathology of the afferent visual pathway (retina or optic nerve anterior to chiasm). *Ischemic optic neuropathy* - While ischemic optic neuropathy (AION) **can** cause APD due to optic nerve ischemia, the question asks for the condition **most commonly** associated. - **Optic neuritis** is more frequently encountered in general practice, particularly in younger patients, while AION typically affects older patients with vascular risk factors. - Both are valid causes of APD, but optic neuritis is the more archetypal teaching example.

Question 7: Isolated painful third nerve palsy is a feature of aneurysms of:

A. Aneurysm of the posterior communicating artery (Correct Answer)
B. Aneurysm of the anterior communicating artery
C. Aneurysm of the vertebrobasillary artery
D. Aneurysm of the ophthalmic artery

Explanation: ***Aneurysm of the posterior communicating artery*** - An aneurysm of the **posterior communicating artery (PCOM)** can compress the ipsilateral **oculomotor nerve (CN III)** as it exits the brainstem. - This compression typically affects the **superficial parasympathetic fibers** first, leading to a **dilated pupil** (mydriasis) along with ophthalmoplegia and ptosis, making the third nerve palsy "painful" and "isolated" without other focal neurological deficits. *Aneurysm of the anterior communicating artery* - Aneurysms of the **anterior communicating artery (ACoM)** are more commonly associated with **subarachnoid hemorrhage** and can cause **visual field defects** or **frontal lobe dysfunction**, but generally not isolated CN III palsy. - While rupture can lead to various neurological deficits, isolated painful third nerve palsy due to ACoM aneurysm is atypical. *Aneurysm of the vertebrobasillary artery* - Aneurysms in the **vertebrobasillar system** typically present with symptoms related to **brainstem compression** or ischemia, such as cranial nerve palsies beyond the third nerve, ataxia, or motor/sensory deficits. - Isolated third nerve palsy is an uncommon presentation for vertebrobasilar aneurysms compared to PCOM aneurysms. *Aneurysm of the ophthalmic artery* - **Ophthalmic artery aneurysms** are usually **intraorbital** and can cause **visual loss** due to direct compression of the **optic nerve (CN II)** or orbital structures. - They are less likely to cause isolated painful third nerve palsy, as the third nerve's course is generally not directly compromised by ophthalmic artery aneurysms.

Question 8: A 27-year-old female patient presents with sudden diminishing vision associated with a relative afferent pupillary defect in the right eye. On examination, the left eye is normal. Which of the following combinations of investigations would be most appropriate?

A. MRI brain and orbits + Visual evoked potentials
B. Visual evoked potentials + Blood tests
C. MRI brain and orbits + Blood tests
D. MRI brain and orbits + Visual evoked potentials + Blood tests (Correct Answer)

Explanation: ***MRI brain and orbits + Visual evoked potentials + Blood tests*** - The combination of **sudden diminishing vision** and a **relative afferent pupillary defect (RAPD)** in one eye strongly suggests **optic neuritis**. - **MRI brain and orbits** is crucial to identify demyelinating lesions characteristic of **multiple sclerosis** and to rule out other causes of optic neuropathy, while **visual evoked potentials (VEPs)** confirm optic nerve dysfunction and can detect subclinical demyelination. **Blood tests** are essential to exclude other inflammatory or autoimmune conditions that can mimic optic neuritis. *MRI brain and orbits + Visual evoked potentials* - While these two investigations are critical for diagnosing **optic neuritis** and assessing for **multiple sclerosis**, they might miss systemic causes of optic neuropathy that can be identified via targeted **blood tests**. - Excluding systemic inflammatory or autoimmune conditions is crucial for complete patient management and preventing recurrence or progression. *Visual evoked potentials + Blood tests* - This combination is insufficient as it omits the **MRI brain and orbits**, which is vital for visualizing the optic nerve and brain for demyelinating lesions and ruling out compressive or infiltrative etiologies. - An **MRI** provides structural information that VEPs and blood tests alone cannot, making it indispensable in this clinical scenario. *MRI brain and orbits + Blood tests* - This combination lacks **Visual evoked potentials (VEPs)**, which provide objective evidence of **optic nerve demyelination** and can detect subclinical involvement, aiding in diagnosis and prognosis. - VEPs are particularly valuable in diagnosing **optic neuritis** and monitoring its recovery or progression.

Question 9: Foster Kennedy syndrome is

A. I/L Papilloedema C/L optic atrophy
B. I/L Optic atrophy and papilloedema
C. I/L Optic atrophy C/L papilloedema (Correct Answer)
D. I/L Papilloedema C/L papillitis

Explanation: ***I/L Optic atrophy C/L papilloedema*** - **Foster Kennedy syndrome** is characterized by **ipsilateral optic atrophy** due to direct compression of the optic nerve by a mass, and **contralateral papilledema** caused by increased intracranial pressure. - This classic presentation strongly points to a **frontal lobe mass** or other intracranial tumor affecting one optic nerve directly and causing generalized raised ICP. *I/L Papilloedema C/L optic atrophy* - This describes the inverse of Foster Kennedy syndrome, which is not the standard presentation for this condition. - It would imply an unusual scenario where two distinct pathologies affect each eye differently. *I/L Optic atrophy and papilloedema* - This option suggests both **optic atrophy** and **papilledema** in the *same* eye, which is a rare combination and not the defining characteristic of Foster Kennedy syndrome. - While it's possible for an atrophic nerve to also show signs of swelling, it does not fit the specific contralateral pattern of Foster Kennedy syndrome. *I/L Papilloedema C/L papillitis* - **Papillitis** is inflammation of the optic disc, often associated with multiple sclerosis or other inflammatory conditions, and typically causes acute vision loss in one eye. - This combination does not represent the specific mechanism or findings of Foster Kennedy syndrome, which involves chronic pressure effects.

Question 10: Early fundoscopic sign in papilloedema is

A. Blurring of the disc margin (Correct Answer)
B. Hyperemia of the disc
C. Splinter hemorrhages
D. Blurring of the peripapillary nerve fiber layer

Explanation: ***Blurring of the disc margin*** - The earliest fundoscopic sign of **papilledema** is the blurring of the superior and inferior optic disc margins, followed by nasal and then temporal margins. - This blurring is due to the **axoplasmic stasis** and edema in the optic nerve head caused by increased intracranial pressure. *Hyperemia of the disc* - While disc **hyperemia** (redness) can occur in papilledema, it typically manifests after the initial blurring of the disc margins. - It results from **venous engorgement** and capillary dilation within the swollen optic disc. *Splinter hemorrhages* - **Splinter hemorrhages** on or near the optic disc are a sign of more advanced or rapidly progressive papilledema, indicating capillary rupture. - These are not usually the *earliest* sign but suggest severe **venous congestion**. *Blurring of the peripapillary nerve fiber layer* - While the **peripapillary nerve fiber layer** does become edematous and blurred in papilledema, the **disc margin blurring** is the *initial* and most characteristic sign identifying the onset of the condition. - This occurs as part of the overall swelling but is often preceded by changes directly at the disc boundary.

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