What are the next steps for a 12-year-old male with a positive Babinski sign?

Immediate Neuroimaging with MRI Brain and Spine

A positive Babinski sign in a 12-year-old is pathological and requires urgent MRI of the brain and spinal cord to identify the underlying upper motor neuron lesion. 1

Initial Diagnostic Approach

The presence of a Babinski sign at age 12 indicates pyramidal tract dysfunction, as this reflex should have disappeared after infancy. 2 The American College of Radiology designates MRI as the preferred imaging modality when a positive Babinski sign is detected, with CT as an alternative only if MRI is contraindicated. 1

Critical Historical Elements to Obtain

• Recent trauma or infection history - may indicate spinal cord injury or transverse myelitis 1
• Progressive weakness, sensory changes, or bowel/bladder dysfunction - suggests thoracic myelopathy or cord compression 1
• Headaches, vision changes, or vomiting - raises concern for increased intracranial pressure 3
• Cognitive changes or behavioral alterations - may indicate intracranial pathology 1
• Fever or systemic illness - could suggest infectious or inflammatory etiology 3

Essential Physical Examination Findings

Assess for additional upper motor neuron signs that localize the lesion:

• Hyperreflexia and spasticity in the lower extremities - confirms upper motor neuron involvement 1
• Muscle weakness patterns - unilateral suggests hemispheric lesion, bilateral suggests spinal cord pathology 2
• Sensory level on the trunk - indicates spinal cord lesion at that dermatomal level 1
• Cranial nerve abnormalities - suggests brainstem or intracranial pathology 3
• Papilledema on fundoscopy - indicates elevated intracranial pressure requiring urgent intervention 3

Differential Diagnosis by Age

In a 12-year-old, the most concerning etiologies include:

• Spinal cord tumors or compression - thoracic myelopathy is a key consideration 1
• Demyelinating disease (multiple sclerosis or acute disseminated encephalomyelitis) - neuroimaging should evaluate for demyelination 3
• Cerebral mass lesions or stroke - though less common in this age group 1
• Genetic disorders - such as 22q11.2 deletion syndrome-related conditions 1
• Infectious/inflammatory myelitis - requires lumbar puncture if imaging shows cord inflammation 3

Imaging Protocol

MRI brain with and without contrast AND MRI complete spine with and without contrast should be obtained urgently. 1 This comprehensive approach is necessary because:

• The lesion could be anywhere along the pyramidal tract from cortex to spinal cord 2
• Spinal cord pathology is particularly important to identify early, as surgical decompression may be required for structural causes of cord compression 1
• Contrast enhancement helps identify inflammatory, infectious, or neoplastic processes 3

Common Pitfall

The Babinski sign has only fair inter-rater reliability (kappa 0.30), meaning different examiners may disagree on its presence. 4 However, when clearly positive in a 12-year-old, this should not delay workup. Consider also assessing foot tapping speed, which has better reliability (kappa 0.73) and 85% agreement with upper motor neuron weakness. 4

Urgent Referral Indications

Immediate neurology or neurosurgery consultation is warranted if:

• Signs of elevated intracranial pressure are present (papilledema, altered mental status, severe headache) 3
• Progressive neurological deficits are occurring 1
• Imaging reveals cord compression requiring surgical decompression 1
• Multiple cranial neuropathies or other neurologic changes are present 3