Neurology Practice Questions

Q: What is the commonest cause of obstructive hydrocephalus in children?

Acqueductal stenosis. **Explanation:** **1. Why Aqueductal Stenosis is Correct:** Aqueductal stenosis is the narrowing of the **Aqueduct of Sylvius** (which connects the third and fourth ventricles). It is the most common cause of **congenital obstructive (non-communicating) hydrocephalus** in infants and children. It can be caused by developmental narrowing, septa formation, or X-linked inheritance (Bickers-Adams syndrome). Because the blockage occurs within the ventricular system, CSF cannot reach the subarachnoid space, leading to proximal ventricular dilatation. **2. Analysis of Incorrect Options:** * **Aqueductal Gliosis:** This is usually a **secondary** process resulting from intrauterine infections (like Toxoplasmosis or CMV) or post-hemorrhagic scarring. While it causes obstruction, primary developmental stenosis is statistically more common. * **Subarachnoid Hemorrhage (SAH):** This typically causes **communicating (non-obstructive) hydrocephalus**. The blood products interfere with the absorption of CSF at the level of the arachnoid villi, rather than blocking the internal flow within the ventricles. * **Tubercular Meningitis (TBM):** TBM is the most common cause of **acquired** hydrocephalus in developing countries. However, it usually results in communicating hydrocephalus due to thick basal exudates blocking the subarachnoid space. **3. NEET-PG High-Yield Pearls:** * **Bickers-Adams Syndrome:** X-linked recessive aqueductal stenosis characterized by hydrocephalus, adducted thumbs, and intellectual disability. * **Clinical Sign:** "Setting-sun" eye phenomenon (downward gaze palsy due to pressure on the midbrain tectum). * **Diagnostic Choice:** MRI is the gold standard to visualize the level of obstruction. * **Treatment:** Endoscopic Third Ventriculostomy (ETV) is often preferred over shunting for aqueductal stenosis.

Q: An adolescent is brought to the emergency department following an episode of myoclonic jerks upon waking. Their consciousness was not impaired. EEG shows generalized 3-4 Hz spike and slow wave complexes. What is the most probable diagnosis?

Juvenile myoclonic epilepsy. **Explanation:** The clinical presentation and EEG findings are classic for **Juvenile Myoclonic Epilepsy (JME)**, also known as Janz syndrome. **Why Option D is Correct:** JME typically presents in **adolescence** (12–18 years). The hallmark is **myoclonic jerks**, which characteristically occur **shortly after awakening**. These jerks are sudden, involuntary muscle contractions, usually involving the arms, and occur without loss of consciousness. The pathognomonic EEG finding is **generalized 4-6 Hz (or 3-4 Hz) polyspike and slow-wave discharges**, often triggered by sleep deprivation or photic stimulation. **Why Other Options are Incorrect:** * **A. Generalized Tonic-Clonic Seizure (GTCS):** While JME patients often experience GTCS later in the disease course, the specific description of isolated myoclonic jerks upon waking points specifically to JME. * **B. Absence Seizure:** These involve brief lapses in consciousness ("staring spells") and are associated with a classic **3 Hz spike-and-wave** pattern. Myoclonic jerks are not the primary feature. * **C. Temporal Lobe Epilepsy:** This is a focal epilepsy. It typically presents with impaired awareness (complex partial seizures), automatisms, and an aura. EEG would show focal temporal spikes, not generalized discharges. **High-Yield Clinical Pearls for NEET-PG:** * **Triggers:** Sleep deprivation, alcohol consumption, and stress are major triggers for JME. * **Treatment of Choice:** **Valproate** is the first-line treatment (highly effective but requires caution in females of childbearing age due to teratogenicity; Levetiracetam is an alternative). * **Prognosis:** JME usually requires **lifelong treatment**, as relapse rates are high (up to 90%) if medications are discontinued. * **EEG Sensitivity:** EEG is most likely to show abnormalities if performed after sleep deprivation.

Q: A mother has a child diagnosed with Duchenne's muscular dystrophy. What is the risk that her next male child will suffer from this illness?

50%. ### Explanation **Concept:** Duchenne Muscular Dystrophy (DMD) follows an **X-linked recessive (XLR)** inheritance pattern. In this scenario, since the mother has already given birth to an affected child, she is an obligate carrier (genotype: $X^D X^d$). When a carrier mother ($X^D X^d$) conceives with an unaffected father ($X^D Y$): * **Male offspring:** There is a **50% chance** the son will inherit the mutated X chromosome ($X^d Y$) and be **affected**, and a 50% chance he will inherit the normal X ($X^D Y$) and be healthy. * **Female offspring:** There is a 50% chance the daughter will be a carrier ($X^D X^d$) and a 50% chance she will be genetically normal ($X^D X^D$). **Analysis of Options:** * **B (50%) is Correct:** This represents the probability specifically for **male** children of a carrier mother. * **A (25%):** This is the risk that any *random* future pregnancy (regardless of sex) will result in an affected child (1 in 4). * **C (100%):** This would only occur if the mother was homozygous for the mutation (extremely rare) or if the father had the disease and the mother was a carrier. * **D (0%):** This is incorrect as the mother is a confirmed carrier. **High-Yield Clinical Pearls for NEET-PG:** * **Gene Mutation:** Deletion of the **Dystrophin gene** (the largest known human gene) located on **Xp21**. * **Clinical Signs:** Gower’s sign (using hands to "climb up" the body to stand) and **pseudohypertrophy** of calves (fatty replacement of muscle). * **Diagnosis:** Gold standard is **Genetic testing** (MLPA); Screening shows massively elevated **Serum Creatine Kinase (CK)**. * **Cause of Death:** Usually respiratory failure or dilated cardiomyopathy in the late teens or early twenties.

Q: A child presents with uncontrollable laughter and precocious puberty. Imaging reveals a lesion, and the diagnosis is confirmed. What is the most probable diagnosis?

Hypothalamic hamartoma. ### Explanation The classic clinical dyad of **Gelastic seizures** (uncontrollable, mirthless laughter) and **Precocious Puberty** is pathognomonic for a **Hypothalamic Hamartoma**. **1. Why Hypothalamic Hamartoma is correct:** Hypothalamic hamartomas are non-neoplastic congenital malformations consisting of heterotopic gray matter located at the base of the hypothalamus (tuber cinereum). They cause: * **Gelastic Seizures:** These originate directly from the hamartoma, which acts as an intrinsic epileptogenic focus. * **Precocious Puberty:** The lesion often contains GnRH-secreting neurons that act as an ectopic pulse generator, triggering the premature onset of the hypothalamic-pituitary-gonadal axis (central precocious puberty). **2. Why the other options are incorrect:** * **Pineal Germinoma:** These typically present with Parinaud syndrome (upgaze palsy) and precocious puberty (due to hCG secretion), but they do not cause gelastic seizures. * **Pituitary Adenoma:** Rare in children; usually presents with hormone excess (e.g., Prolactinoma) or visual field defects (bitemporal hemianopia), not laughter-induced seizures. * **Craniopharyngioma:** These are suprasellar cystic tumors that typically cause **delayed** puberty (due to pituitary stalk compression) and visual disturbances, rather than precocious puberty. **3. NEET-PG High-Yield Pearls:** * **Imaging Gold Standard:** MRI is the investigation of choice; it shows a non-enhancing mass in the region of the tuber cinereum/mamillary bodies. * **Treatment:** Medical management of seizures is often difficult (refractory); surgical excision or thermoablation is preferred. GnRH analogues are used to manage precocious puberty. * **Key Association:** If a child has gelastic seizures, always look for "Dacrystic seizures" (crying fits) as a variant.

Q: A school-going boy is noted to have vacant stares several times a day. There is no history of fever, seizures, or neurological deterioration. What is the diagnosis?

Absence seizures. ### Explanation **Correct Answer: B. Absence Seizures** The clinical presentation of "vacant stares" in a school-aged child, occurring multiple times a day without loss of posture or post-ictal confusion, is the classic hallmark of **Absence Seizures** (formerly Petit Mal epilepsy). These episodes typically last 5–10 seconds and involve a sudden impairment of consciousness without warning. The child may appear to be "daydreaming," and the frequent interruptions in consciousness often lead to declining school performance. **Why other options are incorrect:** * **Atonic Seizures:** These involve a sudden loss of muscle tone ("drop attacks"), causing the patient to fall to the ground. There is no mention of falls or loss of posture here. * **Myoclonic Seizures:** These are characterized by sudden, brief, shock-like muscle contractions (jerks), not vacant staring. * **School Phobia:** While this can cause behavioral issues, it does not manifest as discrete, involuntary episodes of staring or loss of awareness. **High-Yield Clinical Pearls for NEET-PG:** * **EEG Finding:** The pathognomonic feature is a **3 Hz spike-and-wave discharge**, which is generalized and symmetrical. * **Provocation:** Episodes can be triggered by **hyperventilation** or photic stimulation. * **Drug of Choice:** **Ethosuximide** is the first-line treatment. Valproate is an alternative, especially if generalized tonic-clonic seizures (GTCS) coexist. * **Prognosis:** Excellent; most children outgrow absence seizures by adolescence. * **Key Distinction:** Unlike Complex Partial Seizures (Temporal Lobe Epilepsy), absence seizures have **no aura** and **no post-ictal state**.

Q: Landau-Kleffner syndrome is characterized by all of the following except?

Normal EEG during sleep. **Landau-Kleffner Syndrome (LKS)**, also known as **Acquired Epileptic Aphasia**, is a rare childhood neurological disorder characterized by the sudden or gradual loss of language skills (aphasia) in a previously normal child, associated with severe EEG abnormalities. ### **Explanation of Options:** * **Option C (Correct Answer):** The hallmark of LKS is a **markedly abnormal EEG during sleep**. Specifically, it shows "Electrical Status Epilepticus during Sleep" (ESES), characterized by continuous spike-and-wave discharges during non-REM sleep. Therefore, a "Normal EEG during sleep" is incorrect and is the right choice for an "except" question. * **Option A:** Seizures occur in approximately 70–80% of cases. They are usually infrequent, easily controlled, and often disappear by age 15. * **Option B:** The core feature is **acquired aphasia**, typically starting as verbal auditory agnosia (inability to understand spoken words, or "word deafness"). * **Option D:** Brain imaging (CT and MRI) is typically **normal** in LKS, as the disorder is functional/electrophysiological rather than structural. ### **High-Yield Clinical Pearls for NEET-PG:** * **Age of Onset:** Typically between 3 to 7 years. * **Clinical Presentation:** Often mistaken for deafness or autism because the child stops responding to commands. * **EEG Signature:** Spike-wave discharges that are significantly activated by sleep (ESES). * **Management:** Antiepileptic drugs (Valproate, Ethosuximide, Levetiracetam), Corticosteroids (often first-line for EEG improvement), and Speech Therapy. **Avoid Carbamazepine and Phenytoin** as they may worsen the EEG pattern. * **Prognosis:** Language recovery is variable; the earlier the onset, the poorer the linguistic prognosis.

Q: What is the most common type of cerebral palsy?

Spastic. **Explanation:** **Cerebral Palsy (CP)** is a non-progressive permanent disorder of movement and posture caused by an insult to the developing brain. **1. Why Spastic is Correct:** **Spastic CP** is the most common clinical type, accounting for approximately **70% to 80%** of all cases. It results from damage to the **upper motor neurons** (Pyramidal tract) in the motor cortex or corticospinal tracts. It is characterized by increased muscle tone (hypertonia), hyperreflexia, and a positive Babinski sign. The most common subtype within this category is Spastic Diplegia (often associated with prematurity and periventricular leukomalacia). **2. Why Other Options are Incorrect:** * **Atonic (Hypotonic):** This is a rare form characterized by generalized muscle flaccidity and diminished deep tendon reflexes. It is often a transitional phase before the development of spasticity or extrapyramidal features. * **Extrapyramidal (Dyskinetic):** This accounts for about 10–15% of cases. It involves damage to the **basal ganglia**. It presents as choreoathetosis or dystonia and is classically associated with severe neonatal jaundice (kernicterus) or profound perinatal asphyxia. * **Mixed:** This occurs when features of more than one type (e.g., spasticity and athetoid movements) are present. While common in severe cases, it is not the most frequent overall. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Prematurity (leading to Periventricular Leukomalacia/PVL). * **Earliest sign:** Delayed motor milestones or "handedness" appearing before 1 year of age (suggests hemiplegia). * **Scissor Gait:** Classically seen in Spastic Diplegia due to adductor muscle spasticity. * **Diagnosis:** Primarily clinical; MRI is the preferred neuroimaging modality to identify the underlying brain insult.

Q: A 10-year-old boy presents with learning difficulties at school and episodes of brief lapses of awareness with eyelid fluttering every 5-10 minutes. EEG studies reveal 3 Hz spike and wave discharges synchronous in all leads. Which of the following medications is effective for this condition but may cause sedation and tolerance?

Clonazepam. **Diagnosis:** The clinical presentation of brief lapses of awareness, eyelid fluttering, and the pathognomonic **3 Hz spike-and-wave discharges** on EEG confirms a diagnosis of **Childhood Absence Epilepsy (CAE)**. ### **Explanation of Options** * **Clonazepam (Correct):** While Ethosuximide and Valproate are first-line agents, Benzodiazepines like Clonazepam are effective in treating absence seizures. However, their clinical utility is significantly limited by the development of **sedation** and **pharmacological tolerance** (loss of efficacy over time), making them second-line choices. * **Ethosuximide:** This is the **drug of choice** for isolated absence seizures as it lacks the hepatotoxicity of valproate. It works by inhibiting T-type Calcium channels. It does not typically cause significant tolerance. * **Valproic Acid:** This is the drug of choice if absence seizures are associated with Generalized Tonic-Clonic Seizures (GTCS). It is broad-spectrum but carries risks of weight gain and hepatotoxicity. * **Diazepam:** While a benzodiazepine, it is primarily used for the acute termination of status epilepticus (IV/Rectal) rather than the long-term maintenance of absence epilepsy. ### **NEET-PG High-Yield Pearls** * **Drug of Choice (Absence only):** Ethosuximide. * **Drug of Choice (Absence + GTCS/Myoclonic):** Valproic acid. * **EEG Hallmark:** 3 Hz spike-and-wave (generalized, symmetrical, synchronous). * **Provocation:** Seizures can be induced by **hyperventilation** or photic stimulation. * **Contraindicated Drugs:** Carbamazepine, Phenytoin, and Vigabatrin can **exacerbate** absence seizures. * **Mechanism of Clonazepam:** Increases the frequency of GABA-A channel opening.

Question 1

What is the commonest cause of obstructive hydrocephalus in children?

Accepted Answer

Acqueductal stenosis

Answer

Aquaductal gliosis

Answer

Subarachnoid hemorrhage

Answer

Tubercular meningitis

Question 2

An adolescent is brought to the emergency department following an episode of myoclonic jerks upon waking. Their consciousness was not impaired. EEG shows generalized 3-4 Hz spike and slow wave complexes. What is the most probable diagnosis?

Accepted Answer

Juvenile myoclonic epilepsy

Answer

Generalized tonic-clonic seizure

Answer

Absence seizure

Answer

Temporal lobe epilepsy

Question 3

A mother has a child diagnosed with Duchenne's muscular dystrophy. What is the risk that her next male child will suffer from this illness?

Accepted Answer

50%

Answer

25%

Answer

100%

Answer

0%

Question 4

A 6-year-old boy presents with acute onset of difficulty walking and inability to maintain balance. Which of the following is the most likely to allow diagnosis of his condition?

Accepted Answer

Obtain urine drug screen.

Answer

MRI to evaluate his corpus callosum.

Answer

Close scrutiny of his skin for telangiectasia.

Answer

Perform a muscle biopsy of the gastrocnemius muscle.

Question 5

A child presents with uncontrollable laughter and precocious puberty. Imaging reveals a lesion, and the diagnosis is confirmed. What is the most probable diagnosis?

Accepted Answer

Hypothalamic hamartoma

Answer

Pineal germinoma

Answer

Pituitary adenoma

Answer

Craniopharyngioma

Question 6

A 2-year-old boy is brought to the physician by his parents with complaints of continually losing his balance and slurred speech. Physical examination reveals truncal ataxia, a wide-based gait, lethargy, and head bobbing while sitting. Muscle tone is normal. Which anatomic portion of the brain is most likely to harbor a midline tumor in this patient?

Accepted Answer

Cerebellum

Answer

Corpus callosum

Answer

Frontal lobes

Answer

Hypothalamus

Question 7

A school-going boy is noted to have vacant stares several times a day. There is no history of fever, seizures, or neurological deterioration. What is the diagnosis?

Accepted Answer

Absence seizures

Answer

Atonic seizures

Answer

Myoclonic seizures

Answer

School phobia

Question 8

Landau-Kleffner syndrome is characterized by all of the following except?

Accepted Answer

Normal EEG during sleep

Answer

Seizure

Answer

Loss of language skill

Answer

Normal brain CT scan

Question 9

What is the most common type of cerebral palsy?

Accepted Answer

Spastic

Answer

Atonic

Answer

Extrapyramidal

Answer

Mixed

Question 10

A 10-year-old boy presents with learning difficulties at school and episodes of brief lapses of awareness with eyelid fluttering every 5-10 minutes. EEG studies reveal 3 Hz spike and wave discharges synchronous in all leads. Which of the following medications is effective for this condition but may cause sedation and tolerance?

Accepted Answer

Clonazepam

Answer

Diazepam

Answer

Ethosuximide

Answer

Valproic acid

Neurology — MCQs

Neurology — MCQs

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