Neurology Practice Questions

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.

Q: Neurogenic cause of dysphagia includes following except:

Tetany. ***Tetany*** - **Tetany** is characterized by **involuntary muscle contractions** due to electrolyte imbalances (e.g., hypocalcemia) or toxins, primarily affecting peripheral nerves and muscles, not typically considered a neurogenic cause of dysphagia in the context of central nervous system disorders. - While severe muscle spasms can impair swallowing, the underlying pathophysiology of tetany is distinct from the neurological deficits seen in conditions like MS or Parkinson's regarding direct innervation of swallowing muscles. *Multiple sclerosis* - **Multiple sclerosis** is a demyelinating disease of the central nervous system that can affect cranial nerves and brainstem pathways involved in swallowing, leading to **neurogenic dysphagia**. - Lesions in areas controlling **pharyngeal muscles** or **motor planning** for swallowing directly impair the neurological control of this process. *Tetanus* - **Tetanus** is caused by a neurotoxin (tetanospasmin) that blocks inhibitory neurotransmitters, leading to **severe muscle spasms** and rigidity, including those of the jaw (trismus) and pharynx. - The resulting **spastic paralysis** directly interferes with the coordinated muscle movements required for swallowing, making it a neurogenic cause of dysphagia. *Parkinson's disease* - **Parkinson's disease** is a progressive neurodegenerative disorder affecting the basal ganglia, leading to motor symptoms including **bradykinesia**, rigidity, and tremor [1]. - It commonly causes **neurogenic dysphagia** due to impaired coordination, reduced pharyngeal motility, and delayed swallow reflex, impacting all phases of swallowing [2].

Q: A 5-year-old boy presented with a history of focal seizures associated with episodes of impaired consciousness. The patient also has a history of episodic behavioral changes, including agitation and a dream-like state with thrashing movements of his limbs. The child doesn't recall these episodes, and there is no apparent precipitating factor. There is also a family history of seizures. The seizures are often intractable. Lab studies revealed unilateral or bilateral anterior temporal spikes on EEG, hypometabolism on interictal PET, hypoperfusion on interictal SPECT, and material-specific memory deficits on intracranial amobarbital (Wada) test. An MRI of the brain was also performed. Which of the following structures is commonly affected in the above condition?

Hippocampus. ### Hippocampus - The clinical presentation describes **temporal lobe epilepsy**, characterized by focal seizures, impaired consciousness, episodic behavioral changes (agitation, dream-like state, thrashing movements), and memory deficits [1]. - The hippocampus is a key structure within the **temporal lobe** and is commonly affected in temporal lobe epilepsy, often displaying **hippocampal sclerosis** on MRI [2]. *Parietal association cortex* - Dysfunction in the parietal association cortex typically leads to **spatial awareness deficits**, **neglect syndromes**, or **apraxia**, which are not indicated in this case. - Seizures originating here would likely manifest as **somatosensory symptoms** or difficulties with complex motor tasks. *Frontal association cortex* - Seizures originating from the frontal association cortex often present with **complex motor automatisms**, **speech arrest**, or **personality changes**. - While behavioral changes are present, the detailed description of "dream-like state" and memory deficits points more towards temporal lobe involvement. *Occipital association cortex* - Seizures involving the occipital association cortex typically result in **visual disturbances** such as **hallucinations** (e.g., flashing lights, geometric shapes) or **loss of vision**. - These visual symptoms are not mentioned in the patient's presentation.

Q: Bilateral inter nuclear ophthalmoplegia is pathognomonic of-

Multiple sclerosis. Bilateral internuclear ophthalmoplegia (INO) is highly suggestive of multiple sclerosis due to demyelination in the medial longitudinal fasciculus (MLF) on both sides. INO results from a lesion in the MLF, which coordinates conjugate eye movements, leading to impaired adduction on attempted lateral gaze and nystagmus of the abducting eye. *Pontine haemorrhage* - A pontine haemorrhage typically causes a more widespread neurological deficit, including coma, quadriplegia, and pinpoint pupils, rather than isolated INO. - While it can affect the brainstem, primary findings are usually related to mass effect and destruction of vital centers. *Lateral medullary syndrome* - Also known as Wallenberg syndrome, lateral medullary syndrome is caused by infarction of the posterior inferior cerebellar artery (PICA) and presents with vestibular symptoms, ataxia, dysphagia, and contralateral loss of pain and temperature sensation. - It does not directly cause bilateral internuclear ophthalmoplegia as its primary clinical feature. *Pontine glioma* - A pontine glioma is a brain tumor that can affect various cranial nerves and tracts within the pons. - While it can cause some ophthalmoplegia, bilateral internuclear ophthalmoplegia is not its specific or pathognomonic presentation; the clinical picture is usually more diverse and progressive.

Q: Reversible dementia causes are all except-

Lewy body dementia. ***Lewy body dementia*** - **Lewy body dementia** is a **progressive neurodegenerative disease**, characterized by the abnormal accumulation of alpha-synuclein proteins (Lewy bodies) in the brain. - It is an **irreversible form of dementia**, meaning its cognitive decline cannot be halted or reversed. *Subdural hematoma* - A **subdural hematoma**, especially chronic, can cause **cognitive impairment** due to pressure on the brain [1]. - If diagnosed and treated early (e.g., surgical evacuation), the associated cognitive deficits can often be **reversed or significantly improved**. *Myxedema* - **Myxedema**, or severe hypothyroidism, can lead to **reversible cognitive dysfunction**, including memory impairment and slowed thinking. - Treatment with **thyroid hormone replacement** can reverse the dementia-like symptoms. *Vitamin B12 deficiency* - **Vitamin B12 deficiency** can cause a range of neurological symptoms, including **cognitive decline** and dementia-like symptoms [1]. - With timely and adequate **vitamin B12 supplementation**, the associated cognitive impairment can often be **reversed** [1].

Question 1

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 2

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

Accepted Answer

Rigidity

Answer

Fasciculations

Answer

Extensor plantar response

Answer

Wasting

Question 3

Blink reflex is used for:

Accepted Answer

Neuromuscular transmission

Answer

Mid pontine lesions

Answer

Axonal neuropathy

Answer

Motor neuron disease

Question 4

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 5

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 6

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

Question 7

Neurogenic cause of dysphagia includes following except:

Accepted Answer

Tetany

Answer

Multiple sclerosis

Answer

Tetanus

Answer

Parkinson's disease

Question 8

A 5-year-old boy presented with a history of focal seizures associated with episodes of impaired consciousness. The patient also has a history of episodic behavioral changes, including agitation and a dream-like state with thrashing movements of his limbs. The child doesn't recall these episodes, and there is no apparent precipitating factor. There is also a family history of seizures. The seizures are often intractable. Lab studies revealed unilateral or bilateral anterior temporal spikes on EEG, hypometabolism on interictal PET, hypoperfusion on interictal SPECT, and material-specific memory deficits on intracranial amobarbital (Wada) test. An MRI of the brain was also performed. Which of the following structures is commonly affected in the above condition?

Accepted Answer

Hippocampus

Answer

Parietal association cortex

Answer

Frontal association cortex

Answer

Occipital association cortex

Question 9

Bilateral inter nuclear ophthalmoplegia is pathognomonic of-

Accepted Answer

Multiple sclerosis

Answer

Pontine haemorrhage

Answer

Lateral medullary syndrome

Answer

Pontine glioma

Question 10

Reversible dementia causes are all except-

Accepted Answer

Lewy body dementia

Answer

Subdural hematoma

Answer

Myxedema

Answer

Vitamin B12 deficiency

Neurology — MCQs

Neurology — MCQs

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