Neurology Practice Questions

Q: A patient presents with an obnoxious smell and hallucinations. Which brain region lesion is most likely associated with these symptoms?

Temporal lobe lesion. **Explanation:** The clinical presentation of **olfactory hallucinations** (often described as an "obnoxious" or foul smell like burning rubber or garbage) is a classic localizing sign for **Temporal Lobe** pathology. **1. Why Temporal Lobe is Correct:** The primary olfactory cortex is located in the **uncus** and the piriform cortex, which are parts of the medial temporal lobe. Irritative lesions in this area, such as tumors or focal epilepsy (specifically **Uncinate Fits**), trigger these phantom smells. Additionally, the temporal lobe contains the hippocampus and amygdala, which are integral to the limbic system; lesions here frequently manifest as complex sensory hallucinations and emotional disturbances. **2. Why Other Options are Incorrect:** * **Frontal Lobe:** Lesions here typically present with executive dysfunction, personality changes (disinhibition or apathy), and primitive reflexes (e.g., snout, grasp). It does not primarily process sensory hallucinations. * **Parietal Lobe:** This region is responsible for somatosensory processing. Lesions lead to agnosia, apraxia, or disturbances in spatial orientation and body image (e.g., Gerstmann syndrome). * **Occipital Lobe:** This is the visual processing center. Lesions or seizures here result in **visual hallucinations** (often simple flashes or colors) or cortical blindness. **Clinical Pearls for NEET-PG:** * **Uncinate Fits:** Olfactory hallucinations preceding a seizure strongly suggest a temporal lobe origin. * **Schizophrenia vs. Organic:** While auditory hallucinations are common in Schizophrenia, **olfactory and gustatory hallucinations** should always prompt an investigation for organic causes (like temporal lobe epilepsy or tumors). * **Klüver-Bucy Syndrome:** Resulting from bilateral temporal lobe damage, it presents with hypersexuality, hyperphagia, and visual agnosia.

Q: Unilateral proptosis and bilateral 6th nerve palsy are seen in which condition?

Cavernous sinus thrombosis. **Explanation:** **Cavernous Sinus Thrombosis (CST)** is the correct answer due to the unique anatomical relationship between the cavernous sinus and the cranial nerves. 1. **Why it is correct:** The cavernous sinus contains the internal carotid artery and the **Abducens nerve (CN VI)** within the sinus itself (medial to the artery), while CN III, IV, and V1/V2 are in the lateral wall. Because the two cavernous sinuses communicate via the intercavernous plexuses, a septic thrombus (usually from the "danger area" of the face) rapidly spreads from one side to the other. This leads to **bilateral 6th nerve palsy** (the most common and earliest sign). **Proptosis** occurs due to impaired venous drainage from the ophthalmic veins, which may initially be unilateral before progressing. 2. **Why other options are incorrect:** * **Meningitis:** While it can cause multiple cranial nerve palsies due to basal exudates, it typically presents with systemic signs (fever, neck rigidity) and does not cause proptosis. * **Hydrocephalus:** Increased intracranial pressure in hydrocephalus can cause a "false localizing" 6th nerve palsy (often bilateral), but it does not cause proptosis. It is more commonly associated with papilledema and the "setting-sun" sign. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign of CST:** Paralysis of the Abducens nerve (CN VI). * **Most common cause:** *Staphylococcus aureus* infection from the face/nasal area. * **Triad of CST:** Fever, periorbital edema, and chemosis with ophthalmoplegia. * **Differentiating from Orbital Cellulitis:** CST presents with **rapidly bilateral** symptoms and involvement of the opposite eye, whereas orbital cellulitis remains localized for longer.

Q: Bell's palsy is:

An ipsilateral lower motor neuron lesion. **Explanation:** Bell’s palsy is an acute, idiopathic peripheral facial nerve (CN VII) palsy. It is characterized by an **ipsilateral Lower Motor Neuron (LMN) lesion**, meaning the weakness occurs on the same side as the nerve damage. **1. Why Option B is Correct:** The facial nerve nucleus is located in the pons. The fibers originating from this nucleus supply the muscles of facial expression on the same side. In an LMN lesion (like Bell’s palsy), the final common pathway is disrupted, resulting in paralysis of both the **upper and lower quadrants** of the face on the ipsilateral side. Patients cannot wrinkle their forehead, close their eye, or smile on the affected side. **2. Why Other Options are Incorrect:** * **Option A:** This describes **Millard-Gubler Syndrome**, a pontine stroke involving the CN VII nucleus and the corticospinal tract, leading to "crossed hemiplegia." * **Option C & D:** An **Upper Motor Neuron (UMN) lesion** (e.g., stroke) occurs proximal to the facial nucleus. Due to bilateral cortical innervation of the forehead, a UMN lesion results in **contralateral** weakness of only the **lower half** of the face, sparing the forehead [1]. **Clinical Pearls for NEET-PG:** * **Bell’s Phenomenon:** On attempting to close the eye, the eyeball rolls upwards and outwards (seen in LMN lesions). * **Hyperacusis:** Due to paralysis of the stapedius muscle (nerve to stapedius is a branch of CN VII). * **Taste Loss:** Involvement of the chorda tympani leads to loss of taste in the anterior 2/3rd of the tongue. * **Treatment:** Oral corticosteroids (Prednisolone) are the mainstay of treatment; they are most effective when started within 72 hours [1]. Antivirals (Acyclovir) are added only in severe cases or if Ramsay Hunt Syndrome is suspected [1].

Q: Brain death is indicated by suppression of all reflexes except which of the following?

Patellar tendon reflex. The diagnosis of brain death requires the irreversible loss of all functions of the entire brain, including the brainstem [3]. The underlying medical concept is that **brain death is a clinical diagnosis** based on the absence of cerebral and brainstem functions, while the **spinal cord may remain intact.** **1. Why the Patellar Tendon Reflex is correct:** The patellar tendon reflex (knee-jerk) is a **monosynaptic spinal reflex**. Its circuit involves the peripheral nerves and the spinal cord segments (L2-L4), bypassing the brain entirely. Since the spinal cord can remain viable even when the brain is dead, spinal reflexes (including deep tendon reflexes, plantar flexion, or the "Lazarus sign") can still be elicited and do not preclude a diagnosis of brain death. **2. Why the other options are incorrect:** * **Oculovestibular reflex (Caloric testing):** This is a brainstem reflex involving the vestibular nuclei (pons/medulla) and the cranial nerves III and VI [1], [2]. Its absence is a mandatory criterion for brain death. * **Corneal reflex:** This reflex tests the integrity of the trigeminal nerve (afferent) and the facial nerve (efferent), mediated through the pons [1], [2]. * **Pharyngeal (Gag) reflex:** This is a lower brainstem reflex involving the glossopharyngeal and vagus nerves (medulla) [1], [2]. **Clinical Pearls for NEET-PG:** * **Prerequisites for Brain Death Testing:** Normothermia (>36°C), systolic BP ≥100 mmHg, and exclusion of drug intoxication or neuromuscular blocking agents [2]. * **The Apnea Test:** This is the definitive clinical test. A positive result (supporting brain death) is a $PCO_2$ >60 mmHg or >20 mmHg above baseline in the absence of respiratory effort [2]. * **Confirmatory Tests (if clinical exam is inconclusive):** Cerebral angiography (gold standard showing "no flow"), EEG (isoelectric/flat), or Transcranial Doppler.

Q: Which of the following neuronal pathways are implicated in amyotrophic lateral sclerosis?

Involves both upper and lower motor neurons. Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease, is a progressive neurodegenerative disorder characterized by the selective loss of motor neurons. **Why Option D is Correct:** The hallmark of ALS is the **simultaneous involvement of both Upper Motor Neurons (UMN) and Lower Motor Neurons (LMN)** [1, 2]. * **UMN involvement** results from the degeneration of Betz cells in the motor cortex and the corticospinal tracts [1], leading to spasticity, hyperreflexia, and extensor plantar responses (Babinski sign). * **LMN involvement** results from the degeneration of anterior horn cells in the spinal cord [3] and motor nuclei in the brainstem, leading to muscle atrophy, fasciculations, and weakness [2]. **Analysis of Incorrect Options:** * **Option A:** The **posterior columns** (responsible for vibration and proprioception) are characteristically **spared** in ALS [2]. Sensory examination in an ALS patient is typically normal. * **Option B:** Conditions involving **LMN only** include Spinal Muscular Atrophy (SMA) or Polio. ALS must have UMN signs to meet diagnostic criteria (El Escorial criteria). * **Option C:** The **Raphe nuclei** are serotonergic nuclei in the brainstem involved in mood and pain modulation; they are not the primary site of pathology in ALS. **NEET-PG High-Yield Pearls:** * **Senses Spared:** In ALS, sensory systems, bowel/bladder sphincters, and extraocular muscles are typically preserved [2]. * **Genetic Marker:** Mutations in the **SOD1 gene** (Superoxide Sodmutase 1) are common in familial cases; **C9orf72** is the most common genetic cause overall. * **Drug of Choice:** **Riluzole** (glutamate antagonist) is used to extend survival; **Edaravone** (free radical scavenger) is also FDA-approved. * **Split Hand Sign:** Wasting of the thenar eminence (APB/First dorsal interosseous) with relative sparing of the hypothenar eminence is a classic clinical sign.

Q: Uncontrolled flailing of an arm is a symptom of which condition?

Hemiballismus. **Explanation:** **Hemiballismus** is characterized by sudden, wild, large-amplitude, and uncontrolled flailing movements of the limbs on one side of the body. This condition is a classic example of a hyperkinetic movement disorder. **Why Hemiballismus is correct:** The underlying pathology is a lesion of the **contralateral subthalamic nucleus (STN)**, most commonly due to a lacunar stroke. In the indirect pathway of the basal ganglia, the STN normally provides excitatory input to the Globus Pallidus internus (GPi), which inhibits the thalamus. A lesion in the STN reduces this inhibition, leading to an overactive motor cortex and the characteristic violent, "ballistic" movements. **Why the other options are incorrect:** * **Amyotrophic Lateral Sclerosis (ALS):** A progressive neurodegenerative disease affecting both Upper and Lower Motor Neurons. It presents with muscle weakness, wasting, and spasticity, not hyperkinetic flailing. * **Lower Motor Neuron (LMN) Syndrome:** Characterized by flaccid paralysis, muscle atrophy, fasciculations, and loss of reflexes. * **Dysdiadochokinesia:** A sign of **cerebellar dysfunction** defined as the inability to perform rapid, alternating movements (e.g., pronation/supination). **High-Yield Clinical Pearls for NEET-PG:** * **Site of Lesion:** Contralateral Subthalamic Nucleus (STN). * **Most Common Cause:** Vascular (Hemorrhagic or Ischemic stroke). * **Neurotransmitter:** Loss of glutamatergic output from the STN. * **Management:** Dopamine antagonists (like Haloperidol) are often used to control symptoms. * **Comparison:** Unlike Chorea (dance-like, distal), Ballismus is proximal, violent, and large-amplitude.

Question 1

Opsoclonus-myoclonus syndrome is encountered as a clinical feature of which of the following conditions?

Accepted Answer

Cerebral atrophy

Answer

Meningioma

Answer

Excision

Answer

Neurofibromatosis

Question 2

A patient presents with an obnoxious smell and hallucinations. Which brain region lesion is most likely associated with these symptoms?

Accepted Answer

Temporal lobe lesion

Answer

Frontal lobe lesion

Answer

Parietal lobe lesion

Answer

Occipital lobe lesion

Question 3

All of the following are present on the ipsilateral side in Lateral medullary syndrome except?

Accepted Answer

Impaired pain sensation in the body

Answer

Diplopia

Answer

Horner syndrome

Answer

Facial pain

Question 4

Unilateral proptosis and bilateral 6th nerve palsy are seen in which condition?

Accepted Answer

Cavernous sinus thrombosis

Answer

Meningitis

Answer

Hydrocephalus

Answer

None of the above

Question 5

A person develops seizures at a railway station. A wristband indicates they have epilepsy and have medication in their pocket. What is the immediate course of action?

Accepted Answer

Move them away from the train, administer their medication with small sips of water, raise their legs, and wait for the seizure to resolve.

Answer

Place a handkerchief in their mouth and restrain their hands and legs.

Answer

Move them away from the train, administer their medication with small sips of water, and wait for the seizure to resolve.

Answer

Move them away from the train, ensure they are lying down, and refer them to a hospital.

Question 6

Bell's palsy is:

Accepted Answer

An ipsilateral lower motor neuron lesion

Answer

Hemiparesis with contralateral facial nerve palsy

Answer

An ipsilateral upper motor neuron lesion

Answer

Contralateral upper motor neuron lesions

Question 7

Brain death is indicated by suppression of all reflexes except which of the following?

Accepted Answer

Patellar tendon reflex

Answer

Oculovestibular reflex

Answer

Corneal reflex

Answer

Pharyngeal reflex

Question 8

A lesion in the parietal lobe presented with sensory seizures, motor deficits, visual disorders, absence of touch perception on the opposite side, and inability to perceive simultaneous bilateral touch. This is associated with which of the following?

Accepted Answer

Unilateral parietal lobe dysfunction

Answer

Dominant parietal lobe dysfunction

Answer

Non-dominant parietal lobe dysfunction

Answer

Bilateral parietal lobe dysfunction

Question 9

Which of the following neuronal pathways are implicated in amyotrophic lateral sclerosis?

Accepted Answer

Involves both upper and lower motor neurons

Answer

Involves posterior column only

Answer

Involves lower motor neuron only

Answer

Involves Raphe nuclei

Question 10

Uncontrolled flailing of an arm is a symptom of which condition?

Accepted Answer

Hemiballismus

Answer

Amyotrophic lateral sclerosis

Answer

Lower motor neuron syndrome

Answer

Dysdiadochokinesias

Neurology — MCQs

Neurology — MCQs

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