Optic Neuritis — MCQs
Which is the earliest feature of multiple sclerosis ?
Which test is most useful in diagnosing a clinically occult lesion in multiple sclerosis?
Which TB drug causes optic neuritis as a side effect?
Which of the following tests is not required for the diagnosis of multiple sclerosis?
Which of the following drugs is preferred in the management of primary progressive multiple sclerosis?
Which of the following statements about conjunctival lesions is NOT true?
A 35-year-old woman has episodic, painful vision loss in the right eye, left arm tingling, and gait issues. MRI shows white matter lesions in the brain and spine. What is the best treatment for her condition?
All are manifestation of dengue virus infection in eye except?
Which of the following statements is MOST likely false regarding optic neuritis?
In which condition is the swinging light test positive?
Optic Neuritis Indian Medical PG Practice Questions and MCQs
Question 1: Which is the earliest feature of multiple sclerosis ?
- A. Internuclear opthalmoplegia
- B. Cerebellar ataxia
- C. Diplopia
- D. Optic neuritis (Correct Answer)
Explanation: ***Optic neuritis*** - **Optic neuritis** is often the initial manifestation of **multiple sclerosis (MS)**, presenting as monocular vision loss, eye pain, and a relative afferent pupillary defect [3]. - Due to **demyelination** of the optic nerve, it can precede other neurological symptoms by years. *Internuclear ophthalmoplegia* - This condition is characterized by impaired adduction of one eye during conjugate lateral gaze with nystagmus of the abducting eye, caused by a lesion in the **medial longitudinal fasciculus** [1]. - While it is a classic sign of MS, it typically appears later in the disease course, not usually as the **first symptom** [1]. *Cerebellar ataxia* - **Cerebellar ataxia** manifests as incoordination, unsteady gait, and dysarthria, resulting from demyelination in the cerebellum or its pathways [4]. - Although common in MS, it is rarely the **presenting complaint** and generally develops as the disease progresses. *Diplopia* - **Diplopia (double vision)** in MS often results from **cranial nerve palsies** (e.g., abducens nerve palsy) or **internuclear ophthalmoplegia** [2]. - While it can be an early symptom, **optic neuritis** is generally considered the **earliest and most common initial presentation**.
Question 2: Which test is most useful in diagnosing a clinically occult lesion in multiple sclerosis?
- A. Evoked potentials for diagnosing clinically occult lesions in multiple sclerosis
- B. CT scan for large hemispheral strokes
- C. Evoked potentials for brainstem involvement in stroke
- D. MRI for detecting white matter lesions in multiple sclerosis (Correct Answer)
Explanation: **MRI for detecting white matter lesions in multiple sclerosis** - **MRI** is the most sensitive imaging technique for detecting **white matter lesions** characteristic of multiple sclerosis, especially **clinically occult lesions** that do not cause obvious neurological symptoms [1]. - It can identify both new and enhancing lesions (indicating active inflammation) and older, non-enhancing lesions, which is crucial for diagnosis and monitoring disease progression according to the **McDonald criteria**. *Evoked potentials for diagnosing clinically occult lesions in multiple sclerosis* - **Evoked potentials** (e.g., visual, brainstem, somatosensory) can detect slowed conduction in specific neurological pathways, indicative of demyelination, even if the patient is asymptomatic [2]. - While useful for demonstrating dissemination in space if clinical signs are limited, they are **less sensitive than MRI** for detecting the full burden of clinically occult lesions across the entire CNS. *CT scan for large hemispheral strokes* - A **CT scan** is primarily used for rapid detection of **acute hemorrhage** or **large ischemic strokes** due to its speed and availability [1]. - It is **poorly sensitive** for detecting the demyelinating plaques of MS and would not be the primary diagnostic tool for occult lesions in this context. *Evoked potentials for brainstem involvement in stroke* - **Evoked potentials** can assess the integrity of brainstem pathways, and while useful in certain neurological conditions, they are **not the primary diagnostic test for stroke**. - **Neuroimaging (CT or MRI)** is the gold standard for diagnosing stroke and identifying brainstem involvement.
Question 3: Which TB drug causes optic neuritis as a side effect?
- A. Isoniazid
- B. Pyrazinamide
- C. Rifampicin
- D. Ethambutol (Correct Answer)
Explanation: ***Ethambutol*** - **Ethambutol** is known to cause **optic neuritis**, leading to **decreased visual acuity** and impaired **red-green color discrimination**. - This side effect is **dose-dependent** and usually **reversible** upon discontinuing the drug, though permanent damage can occur with prolonged use. *Isoniazid* - **Isoniazid** is primarily associated with **peripheral neuropathy** and **hepatotoxicity**, which can be mitigated with **pyridoxine (vitamin B6)** supplementation. - While visual disturbances can occur, **optic neuritis** is not its most characteristic or frequent ocular side effect. *Pyrazinamide* - The main side effects of **pyrazinamide** include **hepatotoxicity** and **hyperuricemia**, which can lead to **gouty arthritis**. - It does not typically cause **optic neuritis** or other significant ocular complications. *Rifampicin* - **Rifampicin** is well-known for causing **hepatotoxicity**, **red-orange discoloration of body fluids** (urine, tears, sweat), and various **drug interactions** due to enzyme induction. - Ocular side effects like **optic neuritis** are not a common or characteristic adverse effect of rifampicin.
Question 4: Which of the following tests is not required for the diagnosis of multiple sclerosis?
- A. Gadolinium-enhanced MRI
- B. Visual evoked potential
- C. Lumbar puncture
- D. Electronystagmogram (Correct Answer)
Explanation: ***Electronystagmogram*** - An **electronystagmogram (ENG)** measures eye movements and nystagmus, which can be affected by MS but is not a **diagnostic criterion** for the disease. - While vestibulo-ocular dysfunction can occur in MS, an ENG is not required to establish the diagnosis. *Gadolinium-enhanced MRI* - **Gadolinium-enhanced MRI** of the brain and spinal cord is crucial for diagnosing MS as it identifies active lesions (enhancing lesions) and disseminated lesions in space and time [1]. - The presence of both **active and inactive lesions** on MRI helps fulfill the McDonald criteria for MS diagnosis [1]. *Visual evoked potential* - **Visual evoked potentials (VEPs)** measure electrical activity in the brain in response to visual stimuli, detecting subtle damage to the **optic nerve** even in the absence of clinical symptoms [1]. - Abnormal VEPs indicate demyelination and can contribute to fulfilling the **dissemination in space** criterion when lesions are not clearly visible on MRI in specific locations [1]. *Lumbar puncture* - A **lumbar puncture** to analyze **cerebrospinal fluid (CSF)** is often performed to look for **oligoclonal bands** and an **elevated IgG index**, which are characteristic findings in MS. - Although not always mandatory, CSF analysis can support the diagnosis, especially in cases where MRI findings are equivocal or incomplete.
Question 5: Which of the following drugs is preferred in the management of primary progressive multiple sclerosis?
- A. Natalizumab
- B. Ocrelizumab (Correct Answer)
- C. Alemtuzumab
- D. Fingolimod
Explanation: ***Ocrelizumab*** - **Ocrelizumab** is the first and only FDA-approved disease-modifying therapy for **primary progressive multiple sclerosis (PPMS)**, demonstrating a reduction in disability progression. - It is a **monoclonal antibody** that selectively targets CD20-positive B cells, believed to play a critical role in the pathogenesis of MS. *Natalizumab* - **Natalizumab** is approved for **relapsing-remitting multiple sclerosis (RRMS)**, not primary progressive MS [1]. - It works by blocking the migration of immune cells into the **central nervous system**, but carries a risk of **progressive multifocal leukoencephalopathy (PML)**. *Alemtuzumab* - **Alemtuzumab** is used for **relapsing forms of MS**, particularly in patients who have had an inadequate response to other MS drugs [1]. - It is known for its durable efficacy but also its significant side effects, including **autoimmune conditions** and **infusion reactions**. *Fingolimod* - **Fingolimod** is an oral medication approved for **relapsing forms of MS**, but not for primary progressive MS [1]. - It acts by trapping lymphocytes in the **lymph nodes**, preventing them from entering the central nervous system.
Question 6: Which of the following statements about conjunctival lesions is NOT true?
- A. Arise from any part of conjunctiva
- B. Can cause Astigmatism
- C. Surgery is treatment of choice (Correct Answer)
- D. UV exposure is risk factor
Explanation: ***Surgery is treatment of choice*** - While surgery can be used to treat conjunctival lesions, it is not always the **treatment of choice**, especially for smaller, asymptomatic lesions like **pinguecula** which may only require observation and lubrication. - Many conjunctival lesions, such as uncomplicated **pterygium** or **pinguecula**, are managed conservatively unless they cause significant symptoms, vision impairment, or cosmetic concerns. *Arise from any part of conjunctiva* - **Conjunctival lesions** can indeed arise from various parts of the conjunctiva, including the palpebral, bulbar, and forniceal conjunctiva. - For example, **pterygium** typically arises from the bulbar conjunctiva, while **pinguecula** also originates in the bulbar conjunctiva, specifically in the interpalpebral fissure. *Can cause Astigmatism* - Larger **conjunctival lesions**, particularly a **pterygium** that encroaches onto the cornea, can induce or alter astigmatism. - The growth of the lesion can change the **curvature of the cornea**, leading to optical distortion and astigmatism. *UV exposure is risk factor* - **Ultraviolet (UV) light exposure** is a well-established risk factor for the development of many conjunctival lesions, including **pterygium** and **pinguecula**. - Chronic UV exposure leads to **elastotic degeneration** of the conjunctival collagen and is thought to play a key role in the pathogenesis of these growths.
Question 7: A 35-year-old woman has episodic, painful vision loss in the right eye, left arm tingling, and gait issues. MRI shows white matter lesions in the brain and spine. What is the best treatment for her condition?
- A. Levodopa
- B. Plasmapheresis
- C. Acetylcholinesterase inhibitors
- D. Corticosteroids (Correct Answer)
Explanation: Corticosteroids - **Corticosteroids** are the first-line treatment for acute exacerbations of multiple sclerosis (MS) due to their potent anti-inflammatory and immunosuppressive effects [1]. - They help to shorten the duration and severity of attacks by reducing inflammation and edema around demyelinated lesions [1]. *Levodopa* - **Levodopa** is primarily used in the management of **Parkinson's disease** to replenish dopamine levels and improve motor symptoms. - It has no role in treating the acute inflammatory demyelination seen in MS. *Plasmapheresis* - **Plasmapheresis** (plasma exchange) is considered for **severe attacks** of MS that do not respond to high-dose corticosteroids, particularly in acute demyelinating inflammatory polyradiculoneuropathy (AIDP). - It is not typically the initial best treatment for an acute MS exacerbation. *Acetylcholinesterase inhibitors* - **Acetylcholinesterase inhibitors** are primarily used to improve cognitive function in conditions like **Alzheimer's disease** or to manage symptoms of **myasthenia gravis** [2]. - They do not address the underlying inflammatory and demyelinating processes of MS.
Question 8: All are manifestation of dengue virus infection in eye except?
- A. Cataract (Correct Answer)
- B. Vitreous hemorrhage
- C. Maculopathy
- D. Optic neuritis
Explanation: ***Cataract*** - **Cataracts** are primarily associated with aging, congenital factors, trauma, or long-term steroid use, not directly with acute dengue virus infection. - While dengue can cause various ocular manifestations, the formation of cataracts is a **chronic process** that does not fit the typical acute or subacute presentation of dengue-related eye complications. *Vitreous hemorrhage* - **Vitreous hemorrhage** can occur in dengue due to associated **thrombocytopenia** and coagulation abnormalities, leading to bleeding in the eye. - Severe dengue can induce systemic vasculopathy and bleeding tendencies, which may manifest as intraocular hemorrhage. *Maculopathy* - **Dengue maculopathy** is a recognized complication, often presenting as macular edema, hemorrhage, or foveolitis, leading to visual impairment. - This is thought to be due to direct viral effects, immune-mediated responses, or vasculitis affecting the retinal microvasculature. *Optic neuritis* - **Optic neuritis** following dengue infection has been reported, characterized by inflammation of the optic nerve, causing acute vision loss. - This is considered to be an **immune-mediated post-infectious complication** rather than a direct viral cytopathic effect on the nerve.
Question 9: Which of the following statements is MOST likely false regarding optic neuritis?
- A. Abnormal electroretinogram (Correct Answer)
- B. Decreased pupillary reflex
- C. Decreased visual acuity
- D. Abnormal visual evoked potentials (VEP)
Explanation: ***Abnormal electroretinogram*** - Optic neuritis primarily affects the **optic nerve**, which is responsible for transmitting visual information from the retina to the brain. - The **electroretinogram (ERG)** measures the electrical activity of the **retina** in response to light, which is usually normal in optic neuritis as the retina itself is not the primary site of pathology. *Decreased pupillary reflex* - Optic neuritis often causes a **relative afferent pupillary defect (RAPD)**, where the affected eye's pupil dilates instead of constricting when light is swung from the unaffected to the affected eye. - This indicates a decrease in the afferent nerve signal transmission due to damage to the optic nerve. *Decreased visual acuity* - A hallmark symptom of optic neuritis is **acute vision loss**, which can range from mild blurring to severe vision impairment. - This vision loss is typically unilateral and can progress over several days. *Abnormal visual evoked potentials (VEP)* - **VEPs** measure the electrical activity of the brain in response to visual stimuli, assessing the integrity of the optic nerve and visual pathways. - In optic neuritis, the demyelination and damage to the optic nerve cause a **slowing of nerve conduction**, leading to increased latency and reduced amplitude in VEPs.
Question 10: In which condition is the swinging light test positive?
- A. Conjunctivitis
- B. Glaucoma
- C. Keratoconus
- D. Optic neuritis (Correct Answer)
Explanation: ***Optic neuritis*** - The swinging light test (also known as the **Marcus Gunn pupil** or relative afferent pupillary defect, RAPD) is positive when there is a significant **asymmetry in the afferent visual pathway** between the two eyes. - In optic neuritis, the **optic nerve** is inflamed and demyelinated, impairing the transmission of light signals to the brain, which leads to a paradoxical pupillary dilation when the light is swung from the unaffected to the affected eye. *Conjunctivitis* - This is an **inflammation of the conjunctiva**, the membrane lining the eyelid and sclera, which primarily affects the ocular surface. - It does not involve the optic nerve or afferent pupillary pathways, so the swinging light test would be **negative**. *Glaucoma* - Glaucoma is a condition characterized by **progressive optic nerve damage**, often associated with elevated intraocular pressure, leading to peripheral vision loss. - While it causes optic neuropathy, a positive swinging light test is typically seen only in **severe, asymmetric cases** and is not its primary diagnostic feature. *Keratoconus* - This is a non-inflammatory eye condition in which the normally round dome-shaped cornea **thins and bulges outward into a cone-like shape**. - It affects the **cornea's shape and vision quality**, but not the optic nerve or the afferent pupillary reflex pathway, thus the swinging light test would be negative.
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