Neurology Practice Questions

Q: What is the most common age group for febrile seizures?

6 months to 5 years. **Explanation:** **Febrile seizures** are the most common convulsive disorder in the pediatric population. By definition, they occur in children between **6 months and 5 years (60 months) of age**, associated with a fever (>38°C or 100.4°F) that is not caused by a central nervous system (CNS) infection or metabolic imbalance, and in children without a history of prior afebrile seizures. **Why Option B is Correct:** The peak incidence occurs between **12 to 18 months**. The brain in this age group (6 months to 5 years) is uniquely vulnerable to seizures triggered by a rapid rise in temperature due to an immature thermoregulatory system and developing neuronal excitability. **Analysis of Incorrect Options:** * **Option A & D:** Seizures occurring before 6 months of age are rarely "simple" febrile seizures. In infants younger than 6 months, a seizure with fever mandates a workup for **meningitis or encephalitis**, as the clinical signs of meningeal irritation are often absent in this age group. * **Option C:** While many febrile seizures occur before age 2, the clinical definition and risk period extend up to 5 years. Stopping at 2 years would exclude a significant portion of the affected population. **High-Yield Clinical Pearls for NEET-PG:** * **Simple Febrile Seizure:** Generalized tonic-clonic, lasts 15 minutes, or recurs within 24 hours. * **Risk of Recurrence:** Approximately 30% overall; higher if the first seizure occurs before 1 year of age. * **Management:** Reassurance is key. Long-term anticonvulsants are **not** recommended. For abortive therapy (if seizure lasts >5 mins), **Intranasal/IV Midazolam** or **Rectal Diazepam** is used.

Q: An 8-year-old boy presents with difficulty in walking. What is the most likely diagnosis?

Muscular dystrophy. ***Muscular dystrophy*** - **Duchenne muscular dystrophy** is the most common form in boys, typically presenting between ages 3-5 with progressive difficulty walking and **Gower's sign** (using hands to push up from floor). - The **X-linked recessive** inheritance pattern affects boys predominantly, causing **proximal muscle weakness** and **pseudohypertrophy** of calf muscles. *Neuropathy* - Peripheral neuropathy typically presents with **distal weakness** and **sensory loss** starting in hands and feet, not proximal muscle weakness. - Usually associated with **diabetes**, **vitamin deficiencies**, or **hereditary conditions** like Charcot-Marie-Tooth disease, less common in healthy 8-year-olds. *Guillain-Barré syndrome* - An **acute inflammatory demyelinating** condition that develops over days to weeks following an infection. - Characterized by **ascending paralysis**, **areflexia**, and often **respiratory involvement**, requiring immediate medical attention. *Polymyositis* - An **inflammatory myopathy** that typically affects adults, rarely seen in children under 10 years old. - Associated with **elevated muscle enzymes** (CPK, LDH), **muscle pain**, and often systemic symptoms like fever and rash.

Q: What is the commonest cause of non-communicating hydrocephalus in children?

Congenital anomaly. **Explanation:** Hydrocephalus is characterized by an imbalance between cerebrospinal fluid (CSF) production and absorption. **Non-communicating (obstructive) hydrocephalus** occurs when there is a physical blockage within the ventricular system, preventing CSF from reaching the subarachnoid space. **1. Why "Congenital Anomaly" is Correct:** Congenital malformations are the most frequent cause of obstructive hydrocephalus in the pediatric population. Among these, **Aqueductal Stenosis** (narrowing of the Aqueduct of Sylvius) is the single most common specific cause. Other congenital triggers include the Dandy-Walker malformation and Chiari malformations. **2. Analysis of Incorrect Options:** * **Perinatal injury:** While intraventricular hemorrhage (IVH) in premature infants is a major cause, it more frequently leads to *communicating* hydrocephalus due to blood products obliterating the arachnoid villi, though post-hemorrhagic clots can occasionally cause acute obstruction. * **Post-inflammatory obstruction:** Conditions like neonatal meningitis can cause adhesions. While significant, these typically result in communicating hydrocephalus due to basal cistern fibrosis. * **Brain tumors:** While a common cause of *acquired* obstructive hydrocephalus (e.g., medulloblastoma blocking the 4th ventricle), they are statistically less common than congenital structural defects in the overall pediatric age group. **NEET-PG High-Yield Pearls:** * **Most common cause overall:** Aqueductal stenosis (Non-communicating). * **Dandy-Walker Malformation:** Characterized by triad of cystic dilation of the 4th ventricle, cerebellar vermis hypoplasia, and enlarged posterior fossa. * **Clinical Sign:** "Setting-sun" eye phenomenon (downward gaze palsy due to pressure on the midbrain tectum). * **Macewen’s Sign:** "Cracked pot" sound on percussion of the skull due to separated sutures.

Q: Adrenoleukodystrophy is characterized by which mode of inheritance?

X-linked recessive. **Explanation:** **Adrenoleukodystrophy (X-ALD)** is a peroxisomal biogenesis disorder caused by a mutation in the **ABCD1 gene** located on the **X chromosome**. This gene encodes the ALD protein, which is responsible for transporting **Very Long Chain Fatty Acids (VLCFAs)** into peroxisomes for beta-oxidation. A deficiency leads to the systemic accumulation of VLCFAs, particularly in the white matter of the brain, the adrenal cortex, and the Leydig cells of the testes. 1. **Why X-linked Recessive is correct:** The ABCD1 gene is located on the X chromosome (Xq28). As an X-linked recessive trait, it primarily affects males, while females are typically asymptomatic carriers (though they may develop milder myelopathy later in life). 2. **Why other options are incorrect:** * **Autosomal Dominant/Recessive:** These would imply the gene is on a non-sex chromosome. While some peroxisomal disorders (like Zellweger Syndrome) are autosomal recessive, X-ALD is specifically linked to the X chromosome. * **X-linked Dominant:** If this were the case, a single copy of the mutation would cause full clinical disease in all females, which is not the typical presentation of ALD. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad:** Progressive cognitive decline/behavioral issues, vision/hearing loss, and **Adrenal Insufficiency** (Addison’s disease). * **Imaging:** MRI shows characteristic symmetrical enhancement of the **posterior white matter** (occipital and parietal lobes) and the splenium of the corpus callosum. * **Diagnosis:** Elevated plasma levels of **VLCFAs** (C26:0). * **Treatment:** Dietary restriction (Lorenzo’s Oil) has limited efficacy; Hematopoietic Stem Cell Transplant (HSCT) is the treatment of choice in early stages.

Q: A baby is born with a large red, raised discoloration of the face that persists into adulthood. This type of lesion is most likely a component of which of the following syndromes?

Sturge-Weber disease. ### Explanation **Correct Option: D. Sturge-Weber Disease** The "large red, raised discoloration" described is a **Port-wine stain** (Nevus Flammeus). This is a congenital capillary malformation typically found in the distribution of the trigeminal nerve (V1 and V2 branches). Sturge-Weber Syndrome (SWS), also known as encephalotrigeminal angiomatosis, is a neurocutaneous disorder characterized by the triad of: 1. **Facial Port-wine stain** (most common feature). 2. **Leptomeningeal angiomas** (usually ipsilateral to the skin lesion), which can lead to seizures and hemiparesis. 3. **Glaucoma** or vascular malformations of the eye. **Incorrect Options:** * **A & B (Arnold Chiari & Dandy-Walker):** These are structural posterior fossa malformations involving the cerebellum and ventricles. They do not present with cutaneous vascular markers. * **C (Neurofibromatosis):** While this is a neurocutaneous syndrome, its hallmark skin findings are **Café-au-lait spots**, neurofibromas, and axillary freckling (Lisch nodules in the eye), not port-wine stains. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** SWS is sporadic (not inherited) and caused by a somatic mutation in the **GNAQ gene**. * **Radiology:** Skull X-ray or CT may show **"Tram-track" calcifications** (cortical gyriform calcifications) due to underlying leptomeningeal angiomatosis. * **Management:** Port-wine stains are treated with **Pulsed Dye Laser (PDL)**. * **Seizures:** These are often the first neurological symptom, appearing in the first year of life.

Q: The 'sunset sign' is observed in which of the following conditions?

Hydrocephalus. **Explanation:** The **'Sunset Sign'** (or setting-sun phenomenon) is a classic clinical finding in pediatric neurology, most commonly associated with **Hydrocephalus**. **Why Hydrocephalus is correct:** The sign is characterized by the downward deviation of the eyes, where the sclera is visible above the iris, making the eyes look like a "setting sun." This occurs due to increased intracranial pressure (ICP) causing pressure on the **midbrain tectum** and the **periaqueductal region**. This pressure leads to upward gaze palsy (Parinaud’s syndrome) and lid retraction (Collier’s sign). In infants, it is a critical early indicator of hydrocephalus or shunt malfunction, often appearing before significant head circumference enlargement. **Why the other options are incorrect:** * **Optic neuritis:** Typically presents with sudden vision loss, pain with eye movement, and a relative afferent pupillary defect (RAPD), but does not affect eye positioning. * **Thyroid ophthalmopathy:** While it causes lid retraction (Dalrymple sign) and proptosis, it is an autoimmune inflammatory condition of the extraocular muscles, not related to ICP or the sunset sign. * **Orbital cellulitis:** Presents with proptosis, ophthalmoplegia, and fever due to infection, but lacks the specific downward deviation characteristic of the sunset sign. **High-Yield Clinical Pearls for NEET-PG:** * **Macewen’s Sign (Cracked-pot sign):** Resonant percussion note over the skull, also seen in hydrocephalus. * **Parinaud’s Syndrome:** The triad of upward gaze palsy, convergence-retraction nystagmus, and pupillary light-near dissociation (often due to pineal gland tumors). * **Transillumination test:** Useful in infants to differentiate hydrocephalus from hydranencephaly.

Q: A child with mental retardation and a skin rash on the cheeks undergoes a CT scan. What is the most likely diagnosis?

Tuberous sclerosis. ***Tuberous sclerosis*** - The combination of **mental retardation** (intellectual disability) and **skin rash on the cheeks** (adenoma sebaceum) forms part of the classic triad of tuberous sclerosis. - CT scan typically shows **subependymal calcified nodules** (candle-guttering appearance) and **cortical tubers**, which are pathognomonic findings. *Von Hippel-Lindau disease* - Primarily characterized by **retinal angiomas** and **cerebellar hemangioblastomas**, not skin rashes on cheeks. - Associated with **renal cell carcinoma** and **pheochromocytoma**, but intellectual disability is not a typical feature. *Sturge-Weber syndrome* - Features a **port-wine stain** (capillary malformation) typically in the **trigeminal nerve distribution**, not a rash on cheeks. - CT shows **tramtrack calcifications** in the occipital cortex, not subependymal nodules. *Ataxia-telangiectasia* - Characterized by **progressive cerebellar ataxia** and **telangiectasias** on bulbar conjunctiva and skin creases. - Associated with **immunodeficiency** and increased cancer risk, but facial rashes are not typical presentations.

Q: Which of the following can cause acute flaccid paralysis?

All of the above. **Explanation:** Acute Flaccid Paralysis (AFP) is a clinical syndrome characterized by rapid onset of weakness, typically reaching its peak within 1–10 days, accompanied by loss of muscle tone (flaccidity) and absent or diminished deep tendon reflexes. It is a critical differential diagnosis in pediatric neurology. * **Poliomyelitis:** Caused by the Poliovirus, it involves the destruction of **anterior horn cells** in the spinal cord. It typically presents as asymmetrical paralysis with a prodromal febrile illness. * **Tick Paralysis:** Caused by neurotoxins in the saliva of certain female ticks (e.g., *Dermacentor*), which inhibit acetylcholine release at the neuromuscular junction. It presents as a rapidly ascending paralysis that reverses quickly upon removal of the tick. * **Acute Inflammatory Demyelinating Polyneuropathy (AIDP/GBS):** This is the most common cause of AFP in the post-polio era. It is an immune-mediated demyelination of peripheral nerves, typically presenting as symmetrical, ascending paralysis with albuminocytologic dissociation in CSF. Since all three conditions involve the lower motor neuron (LMN) pathway, they all manifest as acute flaccid paralysis. **Clinical Pearls for NEET-PG:** * **Most common cause of AFP worldwide:** Guillain-Barré Syndrome (AIDP). * **Key Diagnostic:** In GBS, look for **Albuminocytologic dissociation** (high protein, normal cell count) in CSF after the first week. * **Differentiating Feature:** Poliomyelitis is usually **asymmetrical** and associated with fever, whereas GBS is **symmetrical** and usually afebrile at the onset of paralysis. * **Botulism:** Another important cause of AFP, but it presents with **descending** paralysis.

Question 1

What is the most common age group for febrile seizures?

Accepted Answer

6 months to 5 years

Answer

1 month to 1 year

Answer

6 months to 2 years

Answer

2 months to 5 years

Question 2

Which corticosteroid is effective in children with cerebral edema?

Accepted Answer

Dexamethasone

Answer

Hydrocortisone

Answer

Prednisolone

Answer

Betamethasone

Question 3

Which of the following statements about Duchenne muscular dystrophy is false?

Accepted Answer

Duchenne muscular dystrophy is less severe than Becker's dystrophy.

Answer

It is an X-linked recessive disorder.

Answer

Dilated cardiomyopathy is a common complication.

Answer

Intellectual impairment is frequently observed.

Question 4

An 8-year-old boy presents with difficulty in walking. What is the most likely diagnosis?

Accepted Answer

Muscular dystrophy

Answer

Neuropathy

Answer

Guillain-Barré syndrome

Answer

Polymyositis

Question 5

What is the commonest cause of non-communicating hydrocephalus in children?

Accepted Answer

Congenital anomaly

Answer

Perinatal injury

Answer

Post-inflammatory obstruction

Answer

Brain tumors

Question 6

Adrenoleukodystrophy is characterized by which mode of inheritance?

Accepted Answer

X-linked recessive

Answer

Autosomal dominant

Answer

Autosomal recessive

Answer

X-linked dominant

Question 7

A baby is born with a large red, raised discoloration of the face that persists into adulthood. This type of lesion is most likely a component of which of the following syndromes?

Accepted Answer

Sturge-Weber disease

Answer

Arnold Chiari malformation

Answer

Dandy-Walker malformation

Answer

Neurofibromatosis

Question 8

The 'sunset sign' is observed in which of the following conditions?

Accepted Answer

Hydrocephalus

Answer

Optic neuritis

Answer

Thyroid ophthalmopathy

Answer

Orbital cellulitis

Question 9

A child with mental retardation and a skin rash on the cheeks undergoes a CT scan. What is the most likely diagnosis?

Accepted Answer

Tuberous sclerosis

Answer

Von Hippel-Lindau disease

Answer

Sturge-Weber syndrome

Answer

Ataxia-telangiectasia

Question 10

Which of the following can cause acute flaccid paralysis?

Accepted Answer

All of the above

Answer

Poliomyelitis

Answer

Tick paralysis

Answer

Acute Inflammatory Demyelinating Polyneuropathy (AIDP)

Neurology — MCQs

Neurology — MCQs

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