Neurology Practice Questions

Q: Deep white matter lesions with bilateral deep bright thalamic appearance are suggestive of which disease?

Krabbe's disease. **Explanation:** **Krabbe’s Disease (Globoid Cell Leukodystrophy)** is a lysosomal storage disorder caused by a deficiency of the enzyme **galactocerebrosidase (GALC)**. This leads to the accumulation of psychosine, which is toxic to oligodendrocytes. * **Imaging Hallmark:** On CT/MRI, Krabbe’s disease characteristically presents with **hyperdensities/T2-hyperintensities** in the **thalami**, caudate nuclei, and posterior limb of the internal capsule. The "deep bright thalamic appearance" combined with white matter involvement is a classic radiologic sign for this condition. **Analysis of Incorrect Options:** * **Alexander Disease:** Characterized by **frontal lobe predominance** of white matter lesions and the presence of Rosenthal fibers. It often presents with macrocephaly. * **Canavan’s Disease:** Notable for diffuse white matter involvement and **macrocephaly**. The hallmark metabolic marker is elevated **N-acetylaspartic acid (NAA)** on MR spectroscopy. * **Metachromatic Leukodystrophy (MLD):** The most common leukodystrophy (Arylsulfatase A deficiency). It typically shows a **"tigroid" or "leopard skin" pattern** of demyelination, sparing the subcortical U-fibers, but does not typically show the bright thalamic sign. **High-Yield Pearls for NEET-PG:** * **Krabbe’s:** Look for "Globoid cells" on biopsy and optic atrophy clinically. * **Thalamic Hyperdensity (CT):** Krabbe’s disease is the classic pediatric association. * **Macrocephaly + Leukodystrophy:** Think Alexander disease or Canavan’s disease. * **Adrenoleukodystrophy:** Predominantly involves the **posterior (occipital)** white matter.

Q: Which of the following is NOT a sign of raised intracranial pressure in a 7-month-old infant?

Papilledema. In infants, the clinical presentation of raised intracranial pressure (ICP) differs significantly from that of older children and adults due to the presence of open cranial sutures and a patent anterior fontanelle. **Why Papilledema is the Correct Answer:** Papilledema (swelling of the optic disc) is rarely seen in infants under the age of 1 year, even with significantly raised ICP. This is because the **open sutures and fontanelles** act as a "safety valve," allowing the skull to expand and accommodate the increased pressure. This decompression prevents the pressure from being transmitted directly to the optic nerve sheath. Therefore, the absence of papilledema does **not** rule out raised ICP in an infant. **Explanation of Incorrect Options:** * **Bulging Fontanelle:** This is the most reliable clinical sign of raised ICP in an infant. When the intracranial volume increases, the non-ossified anterior fontanelle becomes tense and protrudes. * **Increase in Head Size:** Since the cranial sutures are not yet fused, increased pressure leads to "macrocephaly" or a rapid increase in head circumference (crossing percentiles on a growth chart) as the bones are pushed apart. * **Increasing Irritability:** This is a common non-specific behavioral sign of raised ICP. It may be accompanied by a high-pitched cry, poor feeding, or projectile vomiting. **NEET-PG High-Yield Pearls:** * **Macewen’s Sign (Cracked-pot sign):** Percussion of the skull in an infant with raised ICP/hydrocephalus yields a resonant sound due to separated sutures. * **Sunset Sign:** Downward deviation of the eyes (sclera visible above the iris) is a late sign of raised ICP in infants. * **Cushing’s Triad:** Hypertension, bradycardia, and irregular respirations (a late sign of impending herniation).

Q: A 6-year-old child, weighing 20 kg, with a known seizure disorder and already on Valproate 200 mg twice daily, presents with breakthrough seizures to the pediatric casualty. The seizures were aborted with Inj. Lorazepam. What should be the next medication administered to this child?

Sodium Valproate. **Explanation:** The core principle in managing breakthrough seizures in a child already on an Anti-Epileptic Drug (AED) is to **optimize the dose of the current medication** before switching or adding a new class, provided the current drug is appropriate for the seizure type. **Why Sodium Valproate is correct:** The child is currently receiving 400 mg/day (20 mg/kg/day) of Valproate. The standard therapeutic range for Valproate in pediatrics is **20–40 mg/kg/day**. Since the child is at the lower end of the therapeutic window and experiencing breakthrough seizures, the immediate next step is to administer an intravenous loading dose of Sodium Valproate (usually 15–20 mg/kg) to rapidly achieve therapeutic levels and prevent recurrence. **Why other options are incorrect:** * **Phenytoin:** It is a potent hepatic enzyme inducer. Adding it to Valproate complicates metabolism and increases the risk of drug-drug interactions and toxicity. It is generally avoided if Valproate can be optimized. * **Phenobarbitone:** While effective, it causes significant sedation and respiratory depression, especially when used after benzodiazepines (Lorazepam). It is typically reserved for refractory cases or neonatal seizures. * **Levetiracetam:** Although a safe add-on, the priority is to maximize the primary drug (Valproate) that has already been chosen for this patient's specific epilepsy syndrome. **Clinical Pearls for NEET-PG:** * **Valproate Loading Dose:** 20–40 mg/kg IV over 5–10 minutes. * **Drug of Choice:** Valproate is the drug of choice for generalized tonic-clonic seizures (GTCS) and myoclonic seizures in children. * **Status Epilepticus Protocol:** If seizures persist after two doses of benzodiazepines, the next step is a long-acting AED (Fosphenytoin, Valproate, or Levetiracetam). In a patient already on Valproate, Valproate is the preferred choice.

Q: A six-year-old girl presents with brief, irregular contractions in her feet. These symptoms are suspected to be a result of an untreated streptococcal infection. What is the most likely diagnosis?

Sydenham chorea. **Explanation:** The correct answer is **Sydenham chorea (D)**. This condition is a major clinical manifestation of **Acute Rheumatic Fever (ARF)**, occurring due to molecular mimicry where antibodies against Group A Beta-hemolytic Streptococcus (GABHS) cross-react with the basal ganglia (specifically the caudate and putamen). **Why Sydenham Chorea is correct:** It typically presents in children (ages 5–15) weeks to months after a streptococcal pharyngeal infection. The clinical hallmark is "chorea"—brief, purposeless, irregular, involuntary movements—often accompanied by muscular hypotonia and emotional lability. **Analysis of Incorrect Options:** * **A. Chorea gravidarum:** This refers to chorea occurring during pregnancy. While it is often a recurrence of Sydenham chorea triggered by hormonal changes, it is not the primary diagnosis for a six-year-old child. * **B. Chorea major:** This is an archaic term sometimes used for Huntington’s disease or severe chorea, but it is not a standard clinical diagnosis in the context of post-streptococcal sequelae. * **C. Ballism:** This involves large-amplitude, violent, flinging movements of the proximal limbs, usually unilateral (hemiballismus) and typically caused by a lesion in the subthalamic nucleus, not streptococcal infection. **Clinical Pearls for NEET-PG:** * **Jones Criteria:** Sydenham chorea is a **Major Criterion** for the diagnosis of ARF. * **Latent Period:** It has the longest latent period of all ARF features (up to 6 months). * **Clinical Signs:** Look for the **"Milkmaid’s grip"** (irregular contractions of hand muscles), **"Jack-in-the-box tongue"** (inability to protrude the tongue steadily), and **"Pronator sign."** * **Treatment:** Usually self-limiting; however, bed rest and penicillin prophylaxis are essential to prevent rheumatic heart disease. Severe cases may require valproate or carbamazepine.

Q: All of the following are causes of hypotonia in a 2-year-old child, except:

Cerebral palsy. **Explanation:** The core concept in pediatric hypotonia is distinguishing between **Lower Motor Neuron (LMN)** and **Upper Motor Neuron (UMN)** lesions. **Why Cerebral Palsy (CP) is the correct answer:** Cerebral Palsy is a non-progressive UMN disorder caused by an insult to the developing brain. While children with CP may present with transient "floppiness" in early infancy (the hypotonic phase), by age 2, the condition typically evolves into **spasticity** (hypertonia) and hyperreflexia. Therefore, in a 2-year-old, CP is characterized by increased muscle tone rather than persistent hypotonia. **Analysis of Incorrect Options:** * **Trisomy 21 (Down Syndrome):** This is a classic cause of **central (syndromic) hypotonia**. The hypotonia is persistent and associated with joint hyperlaxity and developmental delay. * **Spinal Muscular Atrophy (SMA):** This is an **LMN disorder** involving the anterior horn cells. It presents with profound, progressive hypotonia, "frog-leg" positioning, and absent deep tendon reflexes. * **Congenital Muscular Dystrophy (CMD):** This is a **myopathic cause** of hypotonia. It presents at birth or early childhood with muscle weakness, hypotonia, and often contractures. **Clinical Pearls for NEET-PG:** * **The "Floppy Infant" Rule:** Most cases of neonatal hypotonia are **Central** (80%), but if the infant is alert with severe weakness, suspect **Peripheral** causes (like SMA). * **Evolution of Tone:** CP is the most common cause of "changing tone"—starting as hypotonia and evolving into spasticity. * **Gower’s Sign:** While associated with Duchenne, it can be seen in various muscular dystrophies. * **SMA Type 1 (Werdnig-Hoffmann):** Most common genetic cause of death in infants; look for tongue fasciculations.

Q: What is the most common cause of fatal ventriculomegaly?

Aqueductal Stenosis. **Explanation:** **Aqueductal Stenosis** is the most common cause of congenital obstructive (non-communicating) hydrocephalus, accounting for approximately 33% of cases. It involves a narrowing of the Aqueduct of Sylvius, which connects the third and fourth ventricles. This obstruction leads to significant **ventriculomegaly** (enlargement of the lateral and third ventricles) and is the leading cause of fetal/neonatal macrocephaly requiring surgical intervention. **Analysis of Options:** * **Arnold Chiari Malformation - II (Option B):** While this is the most common cause of hydrocephalus associated with **myelomeningocele**, it is less frequent as an isolated cause of fetal ventriculomegaly compared to aqueductal stenosis. * **Arnold Chiari Malformation - I (Option A):** This typically presents in adolescence or adulthood with cerebellar symptoms (downbeat nystagmus, ataxia) and is rarely a cause of significant fetal ventriculomegaly. * **Dandy Walker Malformation (Option D):** This involves cystic dilation of the fourth ventricle and cerebellar hypoplasia. While it causes hydrocephalus, its incidence is lower than that of aqueductal stenosis. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** "Setting sun" sign (downward gaze), bulging fontanelle, and rapidly increasing head circumference. * **X-ray finding:** "Copper beaten skull" (Luckenschadel skull) due to chronic increased intracranial pressure. * **Associated Infections:** Congenital **Toxoplasmosis** is a classic infectious cause of aqueductal stenosis due to periaqueductal inflammation/scarring. * **Genetic Link:** X-linked hydrocephalus (L1CAM mutation) is the most common inherited form, specifically causing aqueductal stenosis.

Q: What is the most common cause of extradural/subdural hemorrhage in children?

Skull fracture. **Explanation:** In the pediatric population, **trauma** is the leading cause of intracranial hemorrhage. Specifically, **skull fractures** are the most common cause of both extradural (epidural) and subdural hemorrhages. * **Extradural Hemorrhage (EDH):** This usually occurs due to an arterial bleed (most commonly the **middle meningeal artery**) following a skull fracture that lacerates the vessel. In children, the dura is less firmly attached to the skull than in adults, but a forceful impact causing a fracture remains the primary trigger. * **Subdural Hemorrhage (SDH):** While SDH is caused by the tearing of **bridging veins**, these injuries are frequently associated with high-impact trauma and concomitant skull fractures, or in infants, via non-accidental trauma (Shaken Baby Syndrome). **Analysis of Incorrect Options:** * **A. Arteriovenous Malformation (AVM):** While AVMs are a common cause of *intraparenchymal* or *subarachnoid* hemorrhage in children, they are rarely the primary cause of extradural or subdural bleeds. * **C. Aneurysm:** Cerebral aneurysms are rare in children compared to adults and typically present as *subarachnoid* hemorrhage (SAH). * **D. Atherosclerosis:** This is a disease of the elderly and is virtually non-existent as a cause of hemorrhage in the pediatric age group. **Clinical Pearls for NEET-PG:** * **EDH Shape:** Biconvex/Lens-shaped (does not cross sutures). * **SDH Shape:** Crescent-shaped (can cross sutures). * **Lucid Interval:** Classically associated with EDH. * **Non-Accidental Trauma (NAT):** If a child presents with SDH and retinal hemorrhages without a clear history of major trauma, suspect child abuse.

Question 1

Deep white matter lesions with bilateral deep bright thalamic appearance are suggestive of which disease?

Accepted Answer

Krabbe's disease

Answer

Alexander disease

Answer

Canavan's disease

Answer

Metachromatic leukodystrophy

Question 2

Which of the following is NOT a sign of raised intracranial pressure in a 7-month-old infant?

Accepted Answer

Papilledema

Answer

Bulging fontanelle

Answer

Increase in head size

Answer

Increasing irritability

Question 3

A 7-year-old boy has progressive difficulty in climbing stairs, walks with a waddling gait, and also has calf muscle hypertrophy. What is the most likely diagnosis?

Accepted Answer

Becker's Muscular Dystrophy

Answer

Duchenne Muscular Dystrophy (DMD)

Answer

Myositis

Answer

Dermatomyositis

Question 4

A 6-year-old child, weighing 20 kg, with a known seizure disorder and already on Valproate 200 mg twice daily, presents with breakthrough seizures to the pediatric casualty. The seizures were aborted with Inj. Lorazepam. What should be the next medication administered to this child?

Accepted Answer

Sodium Valproate

Answer

Phenobarbitone

Answer

Phenytoin

Answer

Levetiracetam

Question 5

A six-year-old girl presents with brief, irregular contractions in her feet. These symptoms are suspected to be a result of an untreated streptococcal infection. What is the most likely diagnosis?

Accepted Answer

Sydenham chorea

Answer

Chorea gravidarum

Answer

Chorea major

Answer

Ballism

Question 6

All of the following are causes of hypotonia in a 2-year-old child, except:

Accepted Answer

Cerebral palsy

Answer

Trisomy 21

Answer

Spinal muscular atrophy

Answer

Congenital muscular dystrophy

Question 7

What is the most common cause of fatal ventriculomegaly?

Accepted Answer

Aqueductal Stenosis

Answer

Arnold Chiari Malformation - I

Answer

Arnold Chiari Malformation - II

Answer

Dandy Walker Malformation

Question 8

What is the most common cause of extradural/subdural hemorrhage in children?

Accepted Answer

Skull fracture

Answer

Arteriovenous malformation

Answer

Aneurysm

Answer

Atherosclerosis

Question 9

A 9-month-old child develops vomiting and drowsiness following routine immunization. On examination, there is a bulging anterior fontanelle and fundoscopy reveals papilledema. The child develops cranial nerve palsies within a few hours. Despite these findings, the child remains afebrile with a clear chest. What is the most probable diagnosis?

Accepted Answer

Vitamin A toxicity

Answer

Meningitis

Answer

Sagittal sinus thrombosis

Answer

Astrocytoma

Question 10

Which feature differentiates hydranencephaly from hydrocephalus?

Accepted Answer

Cerebral cortex is deficient or hypoplastic in hydranencephaly.

Answer

Hydranencephaly is static while hydrocephalus continues to increase in size.

Answer

Hydranencephaly does not cause an increase in head size.

Answer

All of the above.

Neurology — MCQs

Neurology — MCQs

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