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Difficulty: MediumPediatric Neurologic Disorders

A 4-year-old boy is evaluated in the pediatric clinic due to a 4-week history of increasing unsteadiness and frequent falls. His parents note that he was previously running and climbing without difficulty but has recently begun walking with his feet wide apart. He also complains of head pain upon waking in the mornings, accompanied by two recent episodes of non-bilious emesis. His developmental history was previously normal. On physical examination, his temperature is 37.0°C (98.6°F), blood pressure is 115/75 mm Hg, pulse is 80/min, and respirations are 20/min. Fundoscopic examination reveals blurred optic disc margins bilaterally. He exhibits truncal ataxia and nystagmus on lateral gaze. Which of the following is the most appropriate next step in the management of this patient?

  1. A
    Reassurance and continued observation of gross motor milestones
  2. B
    Lumbar puncture with measurement of opening pressure
  3. Magnetic resonance imaging of the brainAnswer
  4. D
    Administration of oral sumatriptan for migraine management
  5. E
    Electroencephalography to evaluate for subclinical seizures

Answer

Magnetic resonance imaging of the brain
The patient's presentation of a new-onset wide-based gait, morning headaches, vomiting, and bilateral papilledema is highly suspicious for a posterior fossa tumor (such as a medulloblastoma or pilocytic astrocytoma) leading to increased intracranial pressure. The most appropriate next step in management is to obtain neuroimaging, with an MRI of the brain being the modality of choice to clearly delineate the structural anatomy and identify the mass.

Step-by-Step Solution

1
Analyze the patient's presenting symptoms and timeline.
The patient has a 4-week history of morning headaches, non-bilious emesis, and progressive unsteadiness (ataxia).
Identifying the pattern of symptoms helps localize the lesion and determine the acuity of the disease process.
2
Interpret the physical examination findings.
Bilateral blurred optic disc margins (papilledema) indicate increased intracranial pressure, while truncal ataxia and nystagmus localize the pathology to the cerebellum.
Correlating physical findings with symptoms establishes a working clinical diagnosis of a posterior fossa mass.
3
Select the most appropriate next diagnostic step based on the suspected pathology.
Magnetic resonance imaging (MRI) of the brain is chosen to visualize the suspected tumor and evaluate the extent of ventricular enlargement.
MRI is the preferred imaging modality for the posterior fossa, and performing a lumbar puncture is contraindicated due to the risk of herniation from increased intracranial pressure.

Key Concept

Patients presenting with morning headaches, vomiting, papilledema, and cerebellar signs require urgent neuroimaging (preferably an MRI) to evaluate for a posterior fossa tumor. A lumbar puncture is strictly contraindicated in this scenario.
Estimated Time:1m 30s
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Topics

Pediatric Neurologic Disorders

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