Practice high-yield pediatric Central Nervous System (CNS) MCQs covering meningitis, epilepsy, febrile seizures, status epilepticus, cerebral palsy, tuberculous meningitis, ADEM, Guillain-Barré syndrome, hydrocephalus, brain tumors, neuromuscular disorders, and other important neurological conditions. These clinical scenario-based questions are designed to help medical students and postgraduate trainees prepare for FCPS, MD, MRCPCH, MBBS, and Board Examinations with detailed explanations and evidence-based discussions.
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MCQ NO 1: Fever & Vomiting
A 4-year-old boy is brought with a 2-week history of low-grade fever, irritability, decreased playfulness, and intermittent vomiting. Four weeks earlier, he had a generalized febrile rash illness with cough and conjunctivitis from which he recovered. On examination, he is drowsy, has neck stiffness, and right lateral rectus palsy. CSF analysis reveals 180 cells/mm³ (90% lymphocytes), protein 210 mg/dL, and glucose 25 mg/dL (blood glucose 90 mg/dL).
What is the most likely diagnosis?
A. Acute bacterial meningitis
B. Herpes simplex encephalitis
C. Subacute sclerosing panencephalitis
D. Tuberculous meningitis
E. Viral meningitis
Correct answer & Explanation
D. Tuberculous meningitis
Discussion: Tuberculous Meningitis
The child has a subacute presentation with progressive neurological symptoms over 2 weeks, signs of meningeal irritation, and a cranial nerve palsy. The preceding measles infection is an important clue because measles causes transient suppression of cell-mediated immunity, increasing the risk of progression or reactivation of tuberculosis.
The CSF findings are classic for tuberculous meningitis (TBM):
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Lymphocytic pleocytosis
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Markedly elevated protein
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Low CSF glucose
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Subacute course
Cranial nerve palsies, particularly involvement of the sixth cranial nerve, are common in TBM due to basal meningeal inflammation.
Why the Other Options are Incorrect
A. Acute bacterial meningitis
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Usually presents acutely over hours to days.
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CSF typically shows neutrophilic predominance rather than lymphocytosis.
B. Herpes simplex encephalitis
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Characterized by encephalopathy, seizures, and focal neurological deficits.
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CSF glucose is usually normal.
C. Subacute sclerosing panencephalitis
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Occurs years, not weeks, after measles infection.
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Presents with cognitive decline, behavioral changes, and myoclonic jerks.
E. Viral meningitis
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Typically has normal CSF glucose and only mildly elevated protein.
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Cranial nerve palsies are uncommon.
Learning Point
In a child from a tuberculosis-endemic area, a history of recent measles followed by a subacute meningoencephalitic illness with lymphocytic CSF, high protein, low glucose, and cranial nerve palsy should strongly suggest tuberculous meningitis.
MCQ NO 2: Headache & vomiting
An 8-year-old boy presents with a 3-month history of progressive headache, early morning vomiting, and decline in school performance. Over the last 2 weeks, he has developed right-sided weakness and focal seizures involving the right upper limb. On examination, he has papilledema and mild right hemiparesis. MRI brain reveals a large, irregular ring-enhancing lesion in the left frontal lobe with extensive surrounding edema and significant mass effect. There is no fever, and routine blood investigations are unremarkable.
What is the most likely diagnosis?
A. Brain abscess
B. Dysembryoplastic neuroepithelial tumor (DNET)
C. Glioblastoma multiforme
D. Pilocytic astrocytoma
E. Tuberculoma
Correct answer:
Correct Answer
C. Glioblastoma multiform
Explanation:
Discussion: Glioblastoma multiform
This child has features of a high-grade supratentorial space-occupying lesion (SOL):
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Progressive symptoms of raised intracranial pressure
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Focal seizures
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Contralateral hemiparesis
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MRI showing an irregular ring-enhancing lesion with extensive vasogenic edema and mass effect
Although uncommon in children compared with adults, glioblastoma multiforme (WHO Grade 4 diffuse pediatric-type high-grade glioma) is the most likely diagnosis. High-grade gliomas characteristically demonstrate:
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Heterogeneous or ring enhancement
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Central necrosis
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Extensive perilesional edema
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Rapid clinical progression
Why the Other Options Are Incorrect
A. Brain abscess
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May produce ring enhancement but is usually associated with fever, elevated inflammatory markers, congenital heart disease, sinusitis, or otitis.
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Clinical course is generally shorter.
B. Dysembryoplastic neuroepithelial tumor (DNET)
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Typically presents with long-standing epilepsy.
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Usually a cortical lesion with minimal mass effect and little surrounding edema.
D. Pilocytic astrocytoma
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Most commonly arises in the cerebellum.
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Usually a cystic lesion with an enhancing mural nodule rather than an irregular necrotic ring-enhancing mass.
E. Tuberculoma
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Can present as an SOL with seizures, especially in endemic regions.
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Often demonstrates conglomerate ring lesions, may have evidence of systemic tuberculosis, and generally progresses more slowly. Extensive edema can occur, but a solitary irregular necrotic frontal lesion with rapid neurological deterioration is more suggestive of a high-grade glioma.
Key Postgraduate Pearl
In a child with a solitary supratentorial ring-enhancing lesion, the major differential diagnoses are:
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High-grade glioma
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Brain abscess
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Tuberculoma
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Metastasis (rare)
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Tumefactive demyelination
Extensive vasogenic edema, central necrosis, irregular thick ring enhancement, and rapid progression strongly favor a high-grade glioma such as glioblastoma.e
MCQ no 3: Headache & altered sensorium
An 8-year-old boy is brought to the emergency department with fever, headache, and altered sensorium for 2 days. Two weeks earlier, he had an upper respiratory tract infection that resolved spontaneously. On examination, he is confused and disoriented. He has bilateral extensor plantar responses and mild right-sided weakness. There are no meningeal signs. MRI brain shows multiple bilateral, poorly demarcated hyperintense lesions involving the subcortical and deep white matter. CSF reveals mild lymphocytic pleocytosis with normal glucose and mildly elevated protein.
What is the most likely diagnosis?
A. Acute disseminated encephalomyelitis
B. Herpes simplex encephalitis
C. Multiple sclerosis
D. Neuromyelitis optica spectrum disorder
E. Viral meningitis
Correct Answer
Correct Answer
✅ A. Acute disseminated encephalomyelitis
Explanation:
Discussion: Acute disseminated encephlomylitis (ADEM)
ADEM is an immune-mediated demyelinating disorder that typically occurs days to weeks after a viral infection or vaccination. It is characterized by:
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Acute onset of encephalopathy (a required feature for pediatric ADEM diagnosis)
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Multifocal neurological deficits
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MRI showing large, bilateral, asymmetric, poorly defined white matter lesions
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CSF with mild lymphocytic pleocytosis and elevated protein
The presence of encephalopathy together with multifocal MRI lesions following a recent infection strongly favors ADEM.
Why the Other Options Are Incorrect
B. Herpes simplex encephalitis
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Usually affects the temporal lobes.
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Seizures and focal deficits are common.
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MRI typically shows temporal lobe involvement rather than diffuse multifocal white matter lesions.
C. Multiple sclerosis
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Encephalopathy is uncommon at presentation.
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Lesions are usually smaller, well-circumscribed, and periventricular.
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First presentation in childhood is less common.
D. Neuromyelitis optica spectrum disorder
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Typically presents with optic neuritis and/or longitudinally extensive transverse myelitis.
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Diffuse encephalopathy is less characteristic.
E. Viral meningitis
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Usually presents with headache, fever, and meningeal symptoms.
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Multifocal neurological deficits and characteristic MRI white matter lesions are not expected.
Postgraduate Pearl
The single most important clinical clue favoring ADEM over multiple sclerosis in children is the presence of encephalopathy (altered consciousness or behavioral change) accompanying multifocal neurological deficits after a recent infection. MRI typically shows large, poorly marginated bilateral white matter lesions, whereas MS lesions are generally smaller, sharply defined, and periventricular.