Neurology Practice Questions

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: What is the earliest symptom of Tay-Sachs disease?

Exaggerated startle response. ### Explanation **Tay-Sachs Disease (TSD)** is an autosomal recessive lysosomal storage disorder caused by a deficiency of the enzyme **Hexosaminidase A**. This leads to the toxic accumulation of **GM2 gangliosides** within the lysosomes of neurons, resulting in progressive neurodegeneration. **Why "Exaggerated Startle Response" is correct:** The earliest clinical sign of Tay-Sachs disease, typically appearing between **3 to 6 months of age**, is an exaggerated startle response (hyperacusis) to loud noises. This occurs due to early neuronal irritability and dysfunction in the central nervous system before gross motor regression or blindness (amaurosis) becomes apparent. **Why the other options are incorrect:** * **B. Bone deformation:** This is characteristic of **Gaucher disease** (Erlenmeyer flask deformity) or **Hurler syndrome** (dysostosis multiplex), but not Tay-Sachs. * **C. Hepatomegaly:** A crucial diagnostic differentiator is that Tay-Sachs has **no hepatosplenomegaly**. Its presence would instead suggest **Niemann-Pick disease** (Sphingomyelinase deficiency) or Gaucher disease. * **D. Excessive bleeding:** This is not a feature of sphingolipidoses; it is typically associated with platelet disorders or coagulation factor deficiencies. **High-Yield Clinical Pearls for NEET-PG:** * **Cherry-red spot on macula:** A classic finding in both Tay-Sachs and Niemann-Pick. * **Enzyme Deficiency:** Hexosaminidase **A** (Tay-S**A**chs). * **Accumulated Substance:** GM2 Ganglioside. * **Histology:** "Onion-skin" appearance of lysosomes. * **Key Differentiator:** Tay-Sachs = No Hepatosplenomegaly; Niemann-Pick = Hepatosplenomegaly present.

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: Which of the following types of cerebral palsy is most common in low-birth weight infants?

Spastic diplegia. **Explanation:** **Spastic diplegia** is the most common form of cerebral palsy (CP) observed in low-birth-weight (LBW) and preterm infants. The underlying pathophysiology is **Periventricular Leukomalacia (PVL)**. In preterm infants, the watershed area near the lateral ventricles is highly susceptible to ischemia and oxidative stress. This area contains the descending pyramidal tracts; specifically, the fibers subserving the lower extremities are located closest to the ventricles. Damage here results in spasticity that affects the legs more significantly than the arms. **Analysis of Incorrect Options:** * **Spastic Quadriplegia:** This is the most severe form and is typically associated with global hypoxic-ischemic encephalopathy (HIE), severe brain malformations, or multicystic encephalomalacia. It involves all four limbs and is often seen in term infants with severe perinatal asphyxia. * **Choreoathetoid (Dyskinetic) CP:** This type is classically associated with **bilirubin encephalopathy (Kernicterus)** or profound asphyxia affecting the basal ganglia. It is less common now due to effective management of neonatal jaundice. * **Hemiplegia:** This usually results from focal vascular insults, such as a neonatal stroke (middle cerebral artery territory), and is more commonly seen in term infants rather than as a direct consequence of LBW/prematurity. **High-Yield Clinical Pearls for NEET-PG:** * **Most common overall type of CP:** Spastic CP (specifically Spastic Diplegia in preterms). * **Scissor Gait:** A classic clinical sign of spastic diplegia due to increased tone in hip adductors. * **Imaging of choice:** MRI Brain is the gold standard for evaluating the extent of brain injury in CP. * **Key Risk Factor:** Prematurity is the single most important risk factor for the development of CP.

Q: Agenesis of corpus callosum with retinal colobomas and intellectual disability is seen in which condition?

Aicardi syndrome. **Explanation:** **Aicardi Syndrome** is a rare genetic disorder characterized by a classic clinical triad: 1. **Agenesis of the Corpus Callosum** (complete or partial) 2. **Chorioretinal Lacunae** (pathognomonic "punched-out" lesions of the retina/retinal colobomas) 3. **Infantile Spasms** (seizures) It is an **X-linked dominant** condition that is typically **lethal in males**; therefore, it is seen almost exclusively in females. Patients also present with significant intellectual disability and costovertebral defects (e.g., hemivertebrae). **Analysis of Incorrect Options:** * **Alagille Syndrome:** An autosomal dominant disorder caused by *JAG1* mutations. It is characterized by **paucity of interlobular bile ducts** (cholestasis), butterfly vertebrae, peripheral pulmonary artery stenosis, and posterior embryotoxon in the eye. * **Ape Syndrome (Apert Syndrome):** A craniosynostosis syndrome characterized by **mitten-hand syndactyly** (fusion of fingers/toes) and midface hypoplasia. While it may involve CNS anomalies, it lacks the specific retinal lacunae of Aicardi. * **Ataxia Telangiectasia:** An autosomal recessive DNA-repair defect characterized by cerebellar ataxia, **oculocutaneous telangiectasia**, and immunodeficiency. It does not feature agenesis of the corpus callosum. **High-Yield Clinical Pearls for NEET-PG:** * **Aicardi Triad:** Agenesis of corpus callosum + Chorioretinal lacunae + Infantile spasms. * **Genetics:** X-linked Dominant (Male lethal). * **EEG Finding:** Often shows "split-brain" hypsarrhythmia (asynchrony between hemispheres due to lack of corpus callosum). * **Imaging:** MRI is the gold standard to visualize the absent corpus callosum and associated "probst bundles."

Q: A boy presents with weakness in the lower limbs, calf hypertrophy, a positive Gower's sign, and an elevated CPK value of 10,000. What is the most likely diagnosis?

Duchenne Muscular Dystrophy. **Explanation:** The clinical presentation is a classic description of **Duchenne Muscular Dystrophy (DMD)**, an X-linked recessive disorder caused by a mutation in the *Dystrophin* gene. 1. **Why Duchenne Muscular Dystrophy is correct:** * **Calf Hypertrophy:** This is "pseudohypertrophy" where muscle tissue is replaced by fat and connective tissue. * **Gower’s Sign:** Due to proximal muscle weakness (pelvic girdle), the child uses his hands to "climb up" his own body to stand from a sitting position. * **CPK Levels:** Markedly elevated Creatine Phosphokinase (CPK) levels (often >10–50 times the normal limit) are a hallmark of DMD due to ongoing muscle fiber necrosis. 2. **Why other options are incorrect:** * **Spinal Muscular Atrophy (SMA):** This is a lower motor neuron (LMN) disease involving the anterior horn cells. While it presents with weakness, it features **hypotonia, areflexia, and tongue fasciculations** without calf hypertrophy or significantly high CPK. * **Myotonia Congenita:** Characterized by delayed muscle relaxation (myotonia) after contraction (e.g., difficulty releasing a grip), but it does not typically present with progressive weakness or massive CPK elevation. * **Myotonic Dystrophy:** Usually presents in late childhood or adulthood with distal weakness, "hatchet facies," and myotonia. CPK levels are only mildly elevated. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** X-linked Recessive (XLR). * **Diagnosis:** Gold standard is **Genetic testing** (multiplex PCR for deletions); Muscle biopsy shows absent Dystrophin. * **Age of onset:** Usually 3–5 years; non-ambulatory by age 12. * **Common cause of death:** Respiratory failure or Dilated Cardiomyopathy. * **Becker Muscular Dystrophy:** A milder variant where dystrophin is reduced/abnormal rather than absent.

Question 1

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 2

What is the earliest symptom of Tay-Sachs disease?

Accepted Answer

Exaggerated startle response

Answer

Bone deformation

Answer

Hepatomegaly

Answer

Excessive bleeding

Question 3

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 4

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 5

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 6

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.

Question 7

Which of the following types of cerebral palsy is most common in low-birth weight infants?

Accepted Answer

Spastic diplegia

Answer

Spastic quadriplegia

Answer

Choreoathetoid cerebral palsy

Answer

Hemiplegia

Question 8

Agenesis of corpus callosum with retinal colobomas and intellectual disability is seen in which condition?

Accepted Answer

Aicardi syndrome

Answer

Alagille syndrome

Answer

Ape syndrome

Answer

Ataxia telangiectasia

Question 9

A boy presents with weakness in the lower limbs, calf hypertrophy, a positive Gower's sign, and an elevated CPK value of 10,000. What is the most likely diagnosis?

Accepted Answer

Duchenne Muscular Dystrophy

Answer

Spinal Muscular Atrophy

Answer

Myotonia congenita

Answer

Myotonic Dystrophy

Question 10

What is the preferred treatment for Rolandic epilepsy?

Accepted Answer

Carbamazepine

Answer

Phenytoin

Answer

Lamotrigine

Answer

ACTH

Neurology — MCQs

Neurology — MCQs

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