Neurology Practice Questions

Q: Which condition is associated with periodic discharges on EEG at 4-second intervals?

SSPE. ***SSPE*** - **Subacute sclerosing panencephalitis (SSPE)** is a rare, fatal, progressive brain disorder characterized by inflammation and degeneration of the brain. - The distinctive EEG pattern consists of **periodic high-amplitude, slow-wave complexes** that recur every 4-15 seconds, often every 4-8 seconds, making 4-second intervals a key indicator. *Absence Seizure* - Absence seizures typically manifest as **brief staring spells** with impaired consciousness, lasting only a few seconds. - The EEG in absence seizures shows characteristic **generalized 3-Hz spike-and-wave discharges**, not 4-second interval periodic discharges. *REM sleep disorder* - **REM sleep behavior disorder** involves the acting out of vivid dreams due to the absence of normal muscle atonia during REM sleep [1]. - EEG in REM sleep behavior disorder shows normal sleep architecture but may include evidence of **muscle activity (EMG)** during REM sleep, not periodic discharges [1]. *Focal epilepsy* - **Focal epilepsy** originates in a specific area of the brain, causing seizures with symptoms dependent on the affected region [2]. - EEG findings in focal epilepsy typically show **interictal spikes or sharp waves** localized to the region of seizure onset, which are distinct from generalized periodic discharges [2].

Q: Myasthenia gravis is an autoimmune disorder and antibodies against which of the following can cause the disease?

All of the options. ***All of the options*** - Myasthenia gravis is an autoimmune disease primarily characterized by antibodies against **acetylcholine receptors (AChR)**, which accounts for about 85% of cases [1]. - However, approximately 10% of patients have antibodies against **muscle-specific kinase (MuSK)**, and a smaller percentage (1-4%) have antibodies against **low-density lipoprotein receptor-related protein 4 (LRP4)**. *Low-density lipoprotein receptor-related protein 4 (LRP4)* - Antibodies against **LRP4** are found in a subset of myasthenia gravis patients, particularly those who are negative for both AChR and MuSK antibodies. - LRP4 is involved in the formation and maintenance of the **neuromuscular junction**, playing a crucial role in clustering AChRs. *Muscle specific kinase protein (MuSK)* - **MuSK antibodies** are present in 5-10% of myasthenia gravis patients, often presenting with a more focal weakness, particularly affecting bulbar and respiratory muscles. - MuSK is a receptor tyrosine kinase essential for developing and maintaining the postsynaptic specialization of the **neuromuscular junction**. *Acetylcholine receptors (AChR)* - **AChR antibodies** are the most common cause of myasthenia gravis, found in about 85% of patients [1]. - These antibodies block, modulate, or destroy **acetylcholine receptors** at the postsynaptic membrane of the neuromuscular junction, leading to impaired nerve-to-muscle transmission [1].

Q: Risk factors for Alzheimer's include:-

Down's syndrome. ***Down's syndrome*** - Individuals with **Down's syndrome** have an extra copy of chromosome 21, which includes the **amyloid precursor protein (APP) gene**. - Overexpression of APP leads to increased production of **beta-amyloid plaques**, a hallmark pathology of Alzheimer's disease. *Parkinson's disease* - Parkinson's disease is a **neurodegenerative disorder** characterized by motor symptoms due to loss of dopaminergic neurons. - While it can be associated with **dementia (Parkinson's disease dementia)**, it is a distinct condition with different primary pathological mechanisms (alpha-synucleinopathy). *Vascular dementia* - **Vascular dementia** is caused by brain damage from conditions that impair blood flow to the brain, such as strokes or small vessel disease. - It is a **different type of dementia** with distinct etiology and neuropathology compared to Alzheimer's disease. *Huntington's disease* - **Huntington's disease** is a genetic neurodegenerative disorder characterized by involuntary movements (**chorea**), cognitive decline, and psychiatric problems. - It is caused by a mutation in the **Huntingtin gene** and has a specific pathological course unrelated to Alzheimer's.

Q: A patient presented with clinical features of ataxia and incoordination. It is most likely due to involvement of which artery among the following.

Superior cerebellar. ***Superior cerebellar*** - The superior cerebellar artery supplies the **superior cerebellum**, which is critical for **coordination** and balance [1]. - Involvement of this artery commonly leads to **ataxia**, **dysarthria**, and **ipsilateral limb incoordination** [3]. *Middle cerebral* - The middle cerebral artery primarily supplies the **lateral surface of the cerebrum**, including motor and sensory cortices. - Strokes in this territory typically cause **contralateral hemiparesis**, **aphasia**, and **hemianopia**, not ataxia as a primary symptom [2]. *Posterior cerebellar* - The posterior cerebral artery supplies the **occipital lobe**, **thalamus**, and parts of the temporal lobe. - Occlusion often results in **visual field defects** (hemianopia), **memory deficits**, and sometimes **sensory loss**, but not isolated ataxia [2]. *Anterior cerebral* - The anterior cerebral artery supplies the **medial frontal and parietal lobes**. - Its occlusion typically causes **contralateral leg weakness** (hemiparesis), **behavioral changes**, and **urinary incontinence**.

Q: A 30-year-old shows delusions, hallucinations, and marked thought disorder. Labs reveal anti-NMDA receptor antibodies. Best initial treatment?

Immunotherapy. ***Immunotherapy*** - The presence of **anti-NMDA receptor antibodies** indicates an autoimmune etiology for the psychiatric symptoms, making **immunotherapy** (e.g., corticosteroids, IVIG, plasmapheresis) the definitive first-line treatment. - Immunotherapy aims to reduce inflammation and remove autoantibodies, thereby reversing the neurological and psychiatric manifestations. *Benzodiazepines* - While useful for acute agitation or catatonia in psychiatric disorders, **benzodiazepines** do not address the underlying autoimmune pathology of anti-NMDA receptor encephalitis. - They would provide only symptomatic relief and would not prevent disease progression or long-term neurological damage. *ECT* - **Electroconvulsive therapy (ECT)** is a treatment for severe, refractory mood disorders or catatonia, which might be present in anti-NMDA receptor encephalitis. - However, ECT is a symptomatic treatment and does not target the autoimmune cause, making it less appropriate as the **initial definitive treatment**. *Antipsychotics* - **Antipsychotics** are used to manage psychosis, delusions, and hallucinations, which are prominent in anti-NMDA receptor encephalitis. - However, they do not treat the underlying **autoimmune inflammation** and may worsen some symptoms, such as autonomic instability or seizures, in this specific condition.

Q: What is the most sensitive test for diagnosing carpal tunnel syndrome?

Nerve Conduction Study. ***Nerve Conduction Study*** - This test directly measures the speed and amplitude of electrical signals through the **median nerve**, which is compromised in carpal tunnel syndrome. [1] - NCS is considered the **gold standard** for diagnosing carpal tunnel syndrome due to its high sensitivity and specificity in detecting nerve compression. [1] *Hand Grip Strength* - While grip strength can be reduced in advanced cases of carpal tunnel syndrome, it is a **non-specific symptom** and not a sensitive diagnostic measure. [1] - Many conditions affecting the hand or arm can cause decreased grip strength, making it an unreliable primary diagnostic tool. *Phalen's Test* - This **provocative test** involves sustained wrist flexion, which can reproduce symptoms in many patients with carpal tunnel syndrome. - However, it has **variable sensitivity** and specificity; a negative test does not rule out CTS, and other wrist problems can produce a positive result. *Tinel's Sign* - This test involves **tapping over the median nerve** at the wrist to elicit tingling or pain, suggesting nerve irritation. - Similar to Phalen's test, it is a **provocative maneuver** with moderate sensitivity and specificity, and a positive result can occur in other conditions. [1]

Q: A 35-year-old female presents with progressive muscle weakness. EMG shows decremental response. What is the diagnosis?

Myasthenia gravis. ***Myasthenia gravis*** - **Myasthenia gravis** is characterized by **autoantibodies** against **acetylcholine receptors (AChRs)** at the neuromuscular junction, leading to muscle weakness that worsens with repetition [1]. - An **EMG showing a decremental response with repetitive nerve stimulation** is a classic diagnostic finding, indicating impaired neuromuscular transmission [2]. *Multiple sclerosis* - **Multiple sclerosis** is a **demyelinating disease** of the central nervous system, and its EMG findings would typically show evidence of demyelination or axonal loss within the central pathways, not a neuromuscular junction defect. - While it causes progressive weakness, the mechanism and characteristic EMG findings (e.g., **evoked potentials** abnormalities) differ significantly from myasthenia gravis [2]. *ALS* - **Amyotrophic lateral sclerosis (ALS)** is a **motor neuron disease** characterized by degeneration of both upper and lower motor neurons, causing progressive weakness and muscle atrophy. - EMG in ALS typically shows widespread signs of **denervation** and **reinnervation** (e.g., fibrillation potentials, fasciculations, giant motor unit potentials), not a decremental response with repetitive stimulation indicative of a neuromuscular junction disorder. *Guillain-Barré* - **Guillain-Barré syndrome (GBS)** is an **acute demyelinating polyneuropathy** characterized by ascending paralysis and areflexia, usually following an infection. - EMG in GBS typically shows signs of **demyelination** (e.g., prolonged distal latencies, slowed conduction velocities, conduction block), rather than a decremental response at the neuromuscular junction.

Q: A lesion in the cauda equina will likely present with what type of signs?

Lower motor signs. Lower motor signs - The **cauda equina** consists of nerve roots that have **exited the spinal cord** proper, making them part of the **peripheral nervous system**. [2] - Damage to these peripheral nerves results in **lower motor neuron deficits** such as **flaccid paralysis**, **areflexia**, and **muscle atrophy**. [1] *Spastic paralysis* - **Spastic paralysis** is characteristic of **upper motor neuron lesions**, not lesions affecting the peripheral nerves of the cauda equina. - This condition involves increased muscle tone and hyperreflexia due to the disinhibition of spinal reflexes. *Hyperreflexia* - **Hyperreflexia** is typically a sign of an **upper motor neuron lesion**, indicating damage to the neural pathways above the level of the spinal reflex arc. [2] - Lesions of the cauda equina, being lower motor neuron lesions, usually present with **hyporeflexia** or **areflexia**. *Upper motor signs* - **Upper motor neuron signs** (e.g., spasticity, hyperreflexia, positive Babinski sign) arise from damage to the motor pathways within the **brain** or **spinal cord**. - The cauda equina, comprising nerve roots **distal to the spinal cord termination** (conus medullaris), is part of the peripheral nervous system, and its lesions produce lower motor neuron signs. [1]

Q: A 55-year-old man presents with a tremor that occurs when his hands are at rest. He has a slow, shuffling gait and difficulty initiating movement. His symptoms improve with levodopa. What is the most likely diagnosis?

Parkinson’s disease. ***Parkinson’s disease*** - The classic triad of symptoms—**resting tremor**, **bradykinesia** (difficulty initiating movement, shuffling gait), and **rigidity**—is highly characteristic of Parkinson's disease [1, 5]. - Significant improvement with **levodopa** is a hallmark of dopaminergic responsiveness seen in Parkinson's disease. *Huntington’s disease* - Characterized by **chorea** (involuntary, jerky movements), cognitive decline, and psychiatric symptoms, which are not described in this patient. - The onset is typically earlier, and the tremor is not primarily a resting tremor. *Essential tremor* - Primarily an **action tremor** [1] that occurs during voluntary movement, unlike the resting tremor described in the patient. - While it can be debilitating, it typically does not present with **bradykinesia** or **shuffling gait**. *Multiple sclerosis* - A demyelinating disease presenting with a wide range of neurological symptoms depending on lesion location, such as sensory disturbances, weakness, visual problems, and **ataxia**. - While tremors can occur (often intention tremors), the clinical presentation of a **resting tremor**, **shuffling gait**, and **bradykinesia** is not typical of MS.

Q: A 45-year-old man presents with weakness in his right arm and slurred speech that started suddenly 2 hours ago. Which diagnostic test is most appropriate to confirm the diagnosis?

CT scan of the head. ***CT scan of the head*** - A **CT scan of the head** is the most appropriate initial diagnostic test for sudden onset neurological deficits like **weakness** and **slurred speech** to rule out an acute intracranial hemorrhage or ischemic stroke [1]. - It is rapid, widely available, and crucial for guiding immediate management decisions [1]. *Nerve conduction study* - **Nerve conduction studies** are used to evaluate the function of peripheral nerves and muscles, typically for conditions like **neuropathy** or myasthenia gravis, which are not suggested by the acute, focal central nervous system symptoms. - These studies would not provide time-sensitive information about an acute stroke or hemisphere. *Electroencephalogram (EEG)* - An **EEG** measures electrical activity in the brain and is primarily used to diagnose **seizure disorders**, sleep disorders, or assess altered mental status. - It is not indicated for the initial evaluation of sudden focal neurological deficits such as stroke. *MRI of the spine* - An **MRI of the spine** is used to visualize the spinal cord and surrounding structures to diagnose conditions like **spinal cord compression**, disc herniation, or myelitis. - The patient's symptoms of right arm weakness and slurred speech clearly localize to the brain, not the spine.

Question 1

Which condition is associated with periodic discharges on EEG at 4-second intervals?

Accepted Answer

SSPE

Answer

Absence Seizure

Answer

REM sleep disorder

Answer

Focal epilepsy

Question 2

Myasthenia gravis is an autoimmune disorder and antibodies against which of the following can cause the disease?

Accepted Answer

All of the options

Answer

Low-density lipoprotein receptor-related protein 4 (LRP4)

Answer

Muscle specific kinase protein (MuSK)

Answer

Acetylcholine receptors (AChR)

Question 3

Risk factors for Alzheimer's include:-

Accepted Answer

Down's syndrome

Answer

Parkinson's disease

Answer

Vascular dementia

Answer

Huntington's disease

Question 4

A patient presented with clinical features of ataxia and incoordination. It is most likely due to involvement of which artery among the following.

Accepted Answer

Superior cerebellar

Answer

Middle cerebral

Answer

Posterior cerebral

Answer

Anterior cerebral

Question 5

A 30-year-old shows delusions, hallucinations, and marked thought disorder. Labs reveal anti-NMDA receptor antibodies. Best initial treatment?

Accepted Answer

Immunotherapy

Answer

Benzodiazepines

Answer

ECT

Answer

Antipsychotics

Question 6

What is the most sensitive test for diagnosing carpal tunnel syndrome?

Accepted Answer

Nerve Conduction Study

Answer

Hand Grip Strength

Answer

Phalen's Test

Answer

Tinel's Sign

Question 7

A 35-year-old female presents with progressive muscle weakness. EMG shows decremental response. What is the diagnosis?

Accepted Answer

Myasthenia gravis

Answer

Multiple sclerosis

Answer

ALS

Answer

Guillain-Barré

Question 8

A lesion in the cauda equina will likely present with what type of signs?

Accepted Answer

Lower motor signs

Answer

Spastic paralysis

Answer

Hyperreflexia

Answer

Upper motor signs

Question 9

A 55-year-old man presents with a tremor that occurs when his hands are at rest. He has a slow, shuffling gait and difficulty initiating movement. His symptoms improve with levodopa. What is the most likely diagnosis?

Accepted Answer

Parkinson’s disease

Answer

Huntington’s disease

Answer

Essential tremor

Answer

Multiple sclerosis

Question 10

A 45-year-old man presents with weakness in his right arm and slurred speech that started suddenly 2 hours ago. Which diagnostic test is most appropriate to confirm the diagnosis?

Accepted Answer

CT scan of the head

Answer

Nerve conduction study

Answer

Electroencephalogram (EEG)

Answer

MRI of the spine

Neurology — MCQs

Neurology — MCQs

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