Neurology Practice Questions

Q: Myasthenia gravis is a disorder of:

Neuromuscular junction. Neuromuscular junction - **Myasthenia gravis** is an **autoimmune disorder** where antibodies attack **acetylcholine receptors** at the **neuromuscular junction**, impairing nerve-to-muscle communication [1], [2]. - This leads to characteristic **muscle weakness** that worsens with activity and improves with rest [2]. *Spinal cord* - Disorders of the **spinal cord** typically involve sensory, motor, and autonomic deficits below the level of the lesion, often characterized by **spasticity** and **hyperreflexia**. - **Myasthenia gravis** does not directly affect the spinal cord, and its symptoms are distinct from spinal cord pathologies. *Motor neuron* - **Motor neuron diseases** (e.g., **ALS**) primarily affect the motor neurons in the brain and spinal cord, leading to progressive **muscle atrophy**, **fasciculations**, and **weakness** due to **denervation**. - Myasthenia gravis does not involve motor neuron degeneration; the neurons themselves are healthy. *Peripheral nerve* - **Peripheral nerve disorders** (e.g., **Guillain-Barré syndrome**) involve damage to nerves outside the brain and spinal cord, causing sensory changes (numbness, tingling), muscle weakness, and often **diminished reflexes**. - While myasthenia gravis causes weakness, it is due to a problem at the junction between the nerve and muscle, not within the nerve itself.

Q: True about myasthenia gravis:

Skeletal muscle function improves after rest. ***Skeletal muscle function improves after rest*** - Myasthenia gravis is characterized by **fatigue and weakness of skeletal muscles** that worsens with activity and improves with rest [1]. - This fluctuating weakness is a hallmark symptom, distinguishing it from other neuromuscular disorders. *Increased acetylcholine receptors* - Myasthenia gravis involves an **autoimmune attack** against **postsynaptic acetylcholine receptors (AChRs)** at the neuromuscular junction, leading to their **destruction and reduction**, not an increase [2]. - The decreased number of functional AChRs impairs neuromuscular transmission. *Associated with thymoma in 3/4 of cases* - While there is a strong association with thymic abnormalities, especially **thymic hyperplasia** (in 65-70% of cases) and **thymoma** (in 10-15% of cases), stating 3/4 (75%) is an **overestimate** for thymoma [2]. - Thymoma is present in a significant minority, not the vast majority, of myasthenia gravis patients. *Incremental response seen with repetitive electric stimuli* - Repetitive nerve stimulation in myasthenia gravis typically shows a **decremental (fatiguing) response** in the compound muscle action potential (CMAP). - An incremental response is more characteristic of conditions like **Lambert-Eaton myasthenic syndrome**, where presynaptic calcium channel dysfunction is dominant [3].

Q: A female patient of childbearing age is on valproate for JME. Which drug should be used to replace valproate and can be prescribed as monotherapy?

Levetiracetam. ***Levetiracetam*** - **Levetiracetam** is recommended as a safer alternative to valproate in women of childbearing potential due to its **favorable pregnancy safety profile** and broad-spectrum efficacy against generalized seizures, including those seen in **juvenile myoclonic epilepsy (JME)** [1]. - It can be used as **monotherapy** and has a generally well-tolerated side effect profile [1], making it a suitable long-term option.*Carbamazepine* - **Carbamazepine** is primarily effective for **focal (partial) seizures** and is generally not recommended for **generalized epilepsy syndromes** like JME due to the risk of worsening myoclonic or absence seizures. - It also has significant **teratogenic risks**, including neural tube defects, making it unsuitable for women of childbearing age when safer alternatives exist [2].*Phenytoin* - **Phenytoin** is effective for focal and tonic-clonic seizures but can **exacerbate myoclonic seizures** in JME. - It carries a significant risk of **teratogenicity**, including fetal hydantoin syndrome, making it an inappropriate choice for women of childbearing potential [2].*Zonisamide* - **Zonisamide** is a broad-spectrum antiepileptic drug, but it is often reserved as an **add-on therapy** for refractory epilepsy rather than a first-line monotherapy, particularly if there are safer and more established first-line options. - While generally considered less teratogenic than valproate, its safety profile in pregnancy has fewer established data compared to levetiracetam.

Q: Which of the following is the only drug found to be beneficial in halting the progression on EDSS of multiple sclerosis?

Natalizumab. ***Natalizumab*** - **Natalizumab** is a monoclonal antibody that targets the **α4-integrin subunit** on leukocytes, preventing their migration across the blood-brain barrier [1]. - It has been shown to significantly reduce relapse rates and slow the progression of disability (as measured by **EDSS**) in **relapsing-remitting multiple sclerosis (RRMS)**, making it one of the most efficacious disease-modifying therapies. *Glatiramer* - **Glatiramer acetate** is a synthetic polypeptide that acts as a **decoy myelin basic protein**, inducing T-cell responses that may reduce inflammation in the CNS [1]. - While it reduces relapse rates and may slow disability progression, its efficacy in halting progression on the **EDSS** is generally considered less potent than natalizumab. *IFN-beta* - **Interferon-beta (IFN-beta)** modulates the immune system by reducing inflammation and preventing auto-reactive T-cells from attacking myelin. - Although it reduces relapse rates and slows the accumulation of lesions, its impact on completely halting **EDSS** progression is limited, especially compared to newer, more potent therapies. *Methotrexate* - **Methotrexate** is an **immunosuppressant** and **anti-inflammatory** drug, often used in other autoimmune diseases like rheumatoid arthritis. - While it can suppress immune activity, it is **not a primary treatment** for multiple sclerosis and has not shown significant benefit in halting **EDSS** progression in MS.

Q: In which of the following diseases was decrease in levels of a single neurotransmitter first identified?

Parkinson's disease. ***Parkinson's disease*** - The discovery of **decreased dopamine levels** in the **substantia nigra** of Parkinson's patients was a seminal finding in neurobiology. - This identification in the 1960s was one of the first clear links between a **specific neurotransmitter deficit** and a neurological disorder. *Schizophrenia* - While associated with **dopamine dysregulation** (specifically an excess in some pathways), the primary identification was not of a simple decrease in a single neurotransmitter. - The understanding of neurotransmitter involvement in schizophrenia is more complex, involving multiple systems and potentially **excess activity** rather than a deficit. *Huntington's disease* - Characterized by the degeneration of neurons in the **striatum**, leading to a decrease in **GABA** (gamma-aminobutyric acid) and acetylcholine. - The initial identification of a neurotransmitter deficit primarily focused on **GABA**, but this came after the initial findings in Parkinson's. *Alzheimer's disease* - Primarily defined by a significant loss of **cholinergic neurons**, leading to a decrease in **acetylcholine** in the brain. - The discovery of this specific neurotransmitter deficit also occurred after the initial identification in Parkinson's disease.

Q: All of the following are characteristics of Lower motor neuron lesion except

Rigidity. **Rigidity** - **Rigidity** is a characteristic feature of **basal ganglia dysfunction** [2], [3] and is typically seen in conditions like **Parkinson's disease** [2], [3], not in lower motor neuron (LMN) lesions. - It refers to increased muscle tone that is constant throughout the range of passive movement, often described as a **lead-pipe** or **cogwheel** quality [2], [3]. *Fasciculations* - **Fasciculations** are spontaneous, visible, flickering contractions of a small bundle of muscle fibers, which are a hallmark of **denervation** and LMN pathology [1]. - They arise from abnormal hyperexcitability of dying motor neurons or regenerating axons [1]. *Extensor plantar response* - An **extensor plantar response (Babinski sign)** is a classic indicator of an **upper motor neuron (UMN) lesion**, not a lower motor neuron lesion. - In response to stimulation of the sole of the foot, the great toe extends upwards and the other toes fan out, indicating damage to the corticospinal tract. *Wasting* - **Wasting** (muscle atrophy) is a prominent feature of LMN lesions due to the loss of **trophic support** from the motor neuron to the muscle fibers [1]. - Denervated muscles gradually shrink as muscle fibers are lost and replaced by connective tissue and fat [1].

Q: Blink reflex is used for:

Neuromuscular transmission. The blink reflex involves the **facial nerve (CN VII)**, which innervates the **orbicularis oculi muscle**. This pathway critically depends on efficient **neuromuscular transmission** at the motor endplate [1]. Abnormalities in the blink reflex, such as prolonged latency or reduced amplitude, can indicate conditions affecting the transmission of signals from the nerve to the muscle, like **myasthenia gravis** [1]. While the blink reflex arc passes through the brainstem (**pons**), lesions specifically in the **mid pons** are less directly tested by the blink reflex than more caudal pontine lesions or those affecting the trigeminal or facial nerve nuclei. The primary afferent (trigeminal) and efferent (facial) nuclei involved are located in the **lateral pons** and **caudal pons**, respectively. **Axonal neuropathies** primarily affect the **nerve fibers** themselves, leading to reduced nerve conduction velocity or amplitude. While severe axonal damage can affect the blink reflex. However, the blink reflex is more sensitive to issues at the **neuromuscular junction** or **demyelinating neuropathies** that slow conduction in the reflex arc. **Motor neuron disease** (e.g., ALS) primarily affects the **upper and lower motor neurons** [2]. While it can eventually impact facial muscles, the blink reflex is usually preserved in the early stages as it mainly tests the reflex arc and neuromuscular transmission rather than general motor neuron degeneration. The disease typically presents with **muscle weakness**, **atrophy**, and **fasciculations**, which are not directly assessed by the blink reflex itself [2].

Q: Which of the following statements regarding prion diseases is NOT true?

Myoclonus found only in 10% cases. ***Myoclonus found only in 10% cases*** - This statement is incorrect because **myoclonus (sudden, involuntary muscle jerks)** is a very common and prominent feature of **Creutzfeldt-Jakob disease (CJD)** and other prion diseases, occurring in more than 90% of cases as the disease progresses. - The prevalence of myoclonus is significantly higher than 10%, making this an inaccurate representation of the clinical presentation. *They are caused by infectious proteins* - This statement is true; prion diseases are unique neurodegenerative disorders caused by the misfolding and aggregation of a host-encoded protein called the **prion protein (PrP)**. - These rogue proteins, known as **prions (PrPSc)**, can induce normal PrP molecules to misfold, leading to a chain reaction of protein aggregation and neuronal damage [1]. *Brain biopsy is diagnostic* - This statement is true; **brain biopsy** and post-mortem examination are considered definitive diagnostic methods for prion diseases like CJD. - These procedures allow for the detection of **spongiform changes**, **neuronal loss**, and the presence of **PrPSc aggregates** in brain tissue [1]. *Neurodegenerative disease* - This statement is true; prion diseases are characterized by progressive **neurodegeneration**, meaning they cause irreversible damage and loss of neurons in the brain. - This leads to a decline in cognitive function, motor control, and ultimately, death.

Q: The diagnosis of myasthenia gravis is made by a positive edrophonium test, repetitive nerve stimulation test of a weak muscle, and anti-acetylcholine receptor antibody assay. MRI of the mediastinum is now indicated to:

Rule out thymoma. ***Rule out thymoma*** - Up to 15% of patients with **myasthenia gravis** also have a **thymoma**, a tumor of the thymus gland, which is visible on mediastinal imaging [1]. - Surgical removal of the thymoma can lead to improvement in myasthenic symptoms or even remission in some patients. *Look for small cell carcinoma and Lambert-Eaton syndrome* - While **small cell carcinoma** is associated with **Lambert-Eaton myasthenic syndrome (LEMS)**, myasthenia gravis is not typically linked to this specific cancer or paraneoplastic syndrome in the same way [2]. - LEMS is characterized by proximal muscle weakness that *improves* with repeated effort, and a different antibody profile (anti-voltage-gated calcium channels) than myasthenia gravis [2]. *Rule out sarcoidosis* - **Sarcoidosis** is a granulomatous disease that can affect various organs, including the lungs and lymph nodes, but it is not directly associated with the pathophysiology of myasthenia gravis, nor is mediastinal MRI a primary diagnostic tool for sarcoidosis in the context of myasthenia diagnosis. - The clinical presentation and diagnostic pathway for sarcoidosis differ significantly from those for myasthenia gravis. *Rule out tuberculosis before starting prednisone* - Ruling out **tuberculosis** is indeed important before initiating **prednisone** due to the immunosuppressive effects of corticosteroids. - However, the primary indication for mediastinal MRI in a newly diagnosed myasthenia gravis patient is specifically to assess the thymus for **thymoma**, not to screen for tuberculosis [1].

Q: Which of the following seizures has a clinical presentation of impaired consciousness with motor, sensory, or autonomic symptoms which are focal?

Complex partial. ***Complex partial*** - This type of seizure involves **impaired consciousness** (though not complete loss) and usually originates in a specific, **focal area** of the brain [1]. - It presents with various **motor, sensory, or autonomic symptoms** depending on the affected brain region, such as lip smacking, automatisms, or odd sensations [1]. *Simple partial* - While also focal, **consciousness remains intact** during a simple partial seizure, distinguishing it from the described scenario [1]. - Symptoms are often localized and can include motor jerking, sensory changes, or autonomic phenomena, but **without altered awareness** [1]. *Generalized tonic clonic* - This seizure type involves **loss of consciousness** from the onset and affects both sides of the brain, leading to characteristic tonic (stiffening) and clonic (jerking) phases [2]. - It does not present with **focal motor, sensory, or autonomic symptoms** in the way a complex partial seizure does, and consciousness is completely lost [2]. *Status epilepticus* - This is a medical emergency defined as a **prolonged seizure** (typically lasting more than 5 minutes) or **repeated seizures** without full recovery of consciousness between them. - It refers to the duration or pattern of seizures, not a specific seizure type with focal symptoms and impaired consciousness as described.

Question 1

Myasthenia gravis is a disorder of:

Accepted Answer

Neuromuscular junction

Answer

Spinal cord

Answer

Motor neuron

Answer

Peripheral nerve

Question 2

True about myasthenia gravis:

Accepted Answer

Skeletal muscle function improves after rest

Answer

Increased acetylcholine receptors

Answer

Associated with thymoma in 3/4 of cases

Answer

Incremental response seen with repetitive electric stimuli

Question 3

A female patient of childbearing age is on valproate for JME. Which drug should be used to replace valproate and can be prescribed as monotherapy?

Accepted Answer

Levetiracetam

Answer

Carbamazepine

Answer

Phenytoin

Answer

Zonisamide

Question 4

Which of the following is the only drug found to be beneficial in halting the progression on EDSS of multiple sclerosis?

Accepted Answer

Natalizumab

Answer

Glatiramer

Answer

IFN-beta

Answer

Methotrexate

Question 5

In which of the following diseases was decrease in levels of a single neurotransmitter first identified?

Accepted Answer

Parkinson's disease

Answer

Schizophrenia

Answer

Huntington's disease

Answer

Alzheimer's disease

Question 6

All of the following are characteristics of Lower motor neuron lesion except

Accepted Answer

Rigidity

Answer

Fasciculations

Answer

Extensor plantar response

Answer

Wasting

Question 7

Blink reflex is used for:

Accepted Answer

Neuromuscular transmission

Answer

Mid pontine lesions

Answer

Axonal neuropathy

Answer

Motor neuron disease

Question 8

Which of the following statements regarding prion diseases is NOT true?

Accepted Answer

Myoclonus found only in 10% cases

Answer

They are caused by infectious proteins

Answer

Brain biopsy is diagnostic

Answer

Neurodegenerative disease

Question 9

The diagnosis of myasthenia gravis is made by a positive edrophonium test, repetitive nerve stimulation test of a weak muscle, and anti-acetylcholine receptor antibody assay. MRI of the mediastinum is now indicated to:

Accepted Answer

Rule out thymoma

Answer

Look for small cell carcinoma and Lambert-Eaton syndrome

Answer

Rule out sarcoidosis

Answer

Rule out tuberculosis before starting prednisone

Question 10

Which of the following seizures has a clinical presentation of impaired consciousness with motor, sensory, or autonomic symptoms which are focal?

Accepted Answer

Complex partial

Answer

Simple partial

Answer

Generalized tonic clonic

Answer

Status epilepticus

Neurology — MCQs

Neurology — MCQs

On this page

Practice by Chapter

Want unlimited practice?