How should a child with new‑onset headache, dizziness, and lower‑extremity weakness be evaluated and managed?

Pediatric Headache with Dizziness and Lower-Extremity Weakness

A child presenting with new-onset headache, dizziness, and leg weakness requires immediate emergent neuroimaging with CT without contrast to rule out life-threatening intracranial pathology, followed by urgent MRI if CT is negative or equivocal, because this constellation of symptoms represents clear neurological red flags with high risk for serious secondary causes including posterior fossa tumor, stroke, or intracranial hemorrhage. 1, 2

Immediate Assessment and Red Flag Recognition

Perform a complete neurological examination immediately, including:

• Vital signs with blood pressure measurement (hypertension may indicate increased intracranial pressure) 2
• Fundoscopic examination for papilledema (present in 60% of children with brain tumors) 2
• Cranial nerve assessment (deficits present in 94% of children with brain tumors at diagnosis) 2
• Cerebellar function testing (finger-to-nose, heel-to-shin, rapid alternating movements) 2
• Gait evaluation (ataxia is a critical sign of posterior fossa pathology) 2, 3
• Motor strength testing in all extremities (document the pattern and severity of leg weakness) 2
• Sensory examination 2
• Deep tendon reflexes 2
• Mental status assessment 2

The combination of headache with dizziness and leg weakness constitutes multiple neurological red flags that mandate emergent neuroimaging. 1, 2, 4 This presentation has a substantially elevated risk (>10-15%) for life-threatening secondary causes compared to isolated headache (<1%). 4, 3

Critical Red Flags Present in This Case

This patient exhibits at least three major red flags:

• Focal neurological deficit (leg weakness) 2, 4
• Dizziness/vertigo (suggests posterior fossa or brainstem involvement) 4
• Combination of symptoms (multiple neurological signs dramatically increase risk) 3

Additional red flags to assess during history:

• Occipital headache location (rare in children, suggests posterior fossa pathology) 2, 3
• Headache that awakens from sleep 4
• Progressive worsening over days to weeks 4
• Vomiting (especially morning vomiting without nausea) 4
• Age <6 years (higher risk for serious pathology) 4
• Recent onset <6 months 4
• Inability to describe headache quality 3

Emergent Neuroimaging Algorithm

Step 1: Obtain CT head without contrast immediately 1, 2, 5

• CT is the appropriate initial study in the acute/emergency setting because it is rapidly available, does not require sedation, and effectively detects hemorrhage, hydrocephalus, large masses, and other emergencies requiring immediate intervention 1, 5
• CT has 98% sensitivity for acute intracranial hemorrhage 1
• Do not delay imaging for lumbar puncture when focal neurological signs are present 5

Step 2: If CT is negative or shows abnormality requiring further characterization, obtain MRI brain with and without contrast urgently 1, 2

• MRI is superior to CT for detecting posterior fossa tumors, brainstem lesions, stroke, and parenchymal abnormalities 1, 2
• MRI protocol should include: T1-weighted, T2-weighted, FLAIR, diffusion-weighted imaging (for stroke), and post-contrast sequences 2
• Add MRI of the cervical spine if there is concern for spinal cord pathology (leg weakness with preserved arm strength suggests spinal localization) 1

Step 3: Consider MR angiography (MRA) and MR venography (MRV) if vascular pathology is suspected 1

• MRA for arterial dissection or stroke (especially in children with risk factors) 1
• MRV for venous sinus thrombosis (can present with headache and focal deficits) 1

Differential Diagnosis by Likelihood

High-probability life-threatening causes (require immediate identification):

• Posterior fossa tumor (medulloblastoma, ependymoma, pilocytic astrocytoma) - accounts for 2.6% of acute headache presentations; 94% have abnormal neurological findings 2, 3
• Intracranial hemorrhage (arteriovenous malformation, aneurysm rupture) - 1.3% of acute headache presentations 3
• Acute stroke (arterial dissection, moyamoya, sickle cell disease if applicable) 1
• Cerebellar infarction or hemorrhage 1
• Hydrocephalus (obstructive from mass or aqueductal stenosis) 4
• Venous sinus thrombosis 1

Moderate-probability serious causes:

• Chiari I malformation with syrinx (occipital headache worsened by Valsalva, leg weakness from syringomyelia) 2
• Spinal cord tumor or compression 1
• Demyelinating disease (acute disseminated encephalomyelitis, multiple sclerosis) 1
• CNS infection (meningitis, encephalitis, abscess) - but typically presents with fever 4, 3

Lower-probability causes (less likely with this presentation):

• Complicated migraine with hemiplegic features (diagnosis of exclusion after imaging) 4
• Postictal paralysis after seizure (requires witnessed seizure history) 3

Management Pending Imaging Results

While awaiting imaging:

• Keep patient NPO (nothing by mouth) in case emergent neurosurgical intervention is needed 1
• Establish IV access 4
• Monitor vital signs continuously, especially blood pressure and neurological status 2
• Do not administer analgesics that may mask evolving neurological signs until after imaging is complete 4
• Position patient with head of bed elevated 30 degrees if increased intracranial pressure is suspected 1

Common Pitfalls to Avoid

Do not:

• Attribute symptoms to "complicated migraine" or "conversion disorder" without neuroimaging - 94% of children with brain tumors have abnormal neurological findings at diagnosis 2
• Skip fundoscopic examination - papilledema is present in 60% of children with brain tumors and is the most reliable sign of increased intracranial pressure 2
• Order MRI first in the acute setting when CT is more appropriate for rapid assessment 1, 5
• Perform lumbar puncture before neuroimaging when focal neurological signs are present (risk of herniation) 5
• Discharge the patient with "reassurance" if neurological examination is abnormal, even if imaging is initially negative - some lesions require specific MRI sequences or follow-up imaging 2
• Delay imaging to obtain "outpatient MRI" - this presentation requires emergent evaluation 4

Disposition and Follow-Up

If imaging reveals serious pathology:

• Immediate neurosurgical consultation for tumors, hemorrhage, or hydrocephalus 1
• Pediatric neurology consultation for stroke, demyelination, or other medical causes 1
• Admit for observation and further management 1

If initial imaging is negative but symptoms persist:

• Admit for observation and serial neurological examinations 1
• Consider repeat MRI with specific sequences (e.g., MRI spine if not initially performed) 1
• Pediatric neurology consultation for further evaluation 2

The diagnostic yield of neuroimaging in children with abnormal neurological examination is >10-15%, compared to <1% in children with normal examination and no red flags. 2, 4, 3 This patient's presentation with multiple red flags mandates aggressive evaluation.