What are the next steps in workup for a 4-year-old patient with progressive facial asymmetry and a normal brain Magnetic Resonance Imaging (MRI)?

Next Steps in Workup for Progressive Facial Asymmetry with Normal Brain MRI

Given the normal brain MRI with orbits and contrast, immediately refer this child to pediatric neurology and pediatric ophthalmology for comprehensive evaluation, while simultaneously performing detailed facial nerve assessment and obtaining MRI of the face and neck with contrast to evaluate the facial nerve pathway and soft tissue structures. 1, 2

Critical Clinical Assessments Required Now

Comprehensive Facial Nerve Evaluation

• Perform House-Brackmann scale assessment to grade facial nerve function severity, specifically evaluating forehead movement, eye closure completeness, and mouth symmetry both at rest and with voluntary movement. 1, 3
• Check for synkinesis, contracture, or hemifacial spasm, as incomplete facial nerve dysfunction may only become apparent with voluntary facial movement like smiling. 3
• Document whether asymmetry is present at rest or only with dynamic facial expressions, as this distinction is critical but does not exclude serious pathology. 3

Complete Ophthalmological Assessment

• Test visual acuity, binocular alignment using prism and alternate cover test at distance and near, and extraocular muscle function (ductions and versions) to exclude strabismus with compensatory head posture mimicking structural facial asymmetry. 4, 1, 2
• Perform fundoscopic examination and assess for any compensatory head tilt or torticollis that could indicate ocular misalignment. 4, 1
• Evaluate sensory testing including fusion and stereoacuity if the child can cooperate. 4

Detailed Neurological Examination

• Complete cranial nerve assessment beyond just facial nerve (CN VII), testing all cranial nerves systematically, motor and sensory function throughout, and cerebellar function. 1, 2
• Assess for any developmental delays, regression of motor skills, or loss of strength that would indicate progressive neurological disease. 3

Additional Imaging Required

MRI Face and Neck with Contrast

Order MRI of the face and neck with contrast (rated 9/9 "usually appropriate" by ACR) to evaluate the entire facial nerve pathway from brainstem to peripheral branches, as tumors, schwannomas, meningeal infiltration, or vascular malformations require contrast for detection. 3, 5

The rationale is compelling: while brain MRI with orbits was normal, facial nerve tumors or schwannomas can occur along the extracranial facial nerve pathway, and enhancing lesions may be missed without dedicated face/neck imaging with contrast. 3 Non-contrast studies miss critical pathologies including isodense tumors and subtle masses. 3

Mandatory Specialty Referrals

Immediate Pediatric Neurology Referral

Refer urgently to pediatric neurology for evaluation of possible intracranial or neurological causes, even with normal brain MRI, as progressive facial asymmetry may represent early manifestation of conditions not yet visible on imaging. 1, 2

The case report of a 4-year-old with sphenoid wing meningioma presenting initially with only facial asymmetry underscores that dismissing facial paralysis without thorough evaluation can be disastrous. 6

Immediate Pediatric Ophthalmology Referral

Refer to pediatric ophthalmology for comprehensive examination to definitively exclude strabismus with compensatory head posture, which can mimic structural facial asymmetry. 1, 2, 3

Differential Diagnosis Priority After Normal Brain MRI

With normal brain MRI with orbits and contrast, the differential shifts but remains serious:

• Facial nerve disorders: Bell's palsy (atypical presentation), facial nerve tumor along extracranial pathway, or facial nerve schwannoma. 2, 3
• Strabismus with compensatory head posture: Can cause apparent facial asymmetry and requires ophthalmological expertise to diagnose. 2, 3
• Hemifacial microsomia or other congenital malformations: Progressive with growth, showing increasing asymmetry over time. 1, 7
• Soft tissue or skeletal developmental asymmetry: Requires 3D-CT maxillofacial scan only after neurological causes are completely excluded. 1

Critical Pitfalls to Avoid

Do not assume benign structural asymmetry based solely on normal brain MRI—the one-year progressive course in a 4-year-old demands complete evaluation of the facial nerve pathway and exclusion of strabismus. 1, 3

Do not delay evaluation or assume dynamic-only asymmetry is benign, as facial asymmetry may be the first sign of a process requiring urgent attention. 3

Do not order 3D-CT maxillofacial scan yet due to unnecessary radiation exposure when additional MRI imaging is indicated first. 1

Distinguish between true anatomical asymmetry and functional asymmetry from compensatory posturing, as strabismus can mimic structural facial asymmetry. 1, 3

Documentation Requirements

• Document exact onset timing (one year ago), rate of progression, birth weight, gestational age, prenatal/perinatal history, developmental milestones, and any history of head trauma. 1
• Record facial asymmetry pattern by evaluating midline vertical alignment through glabella, nasal dorsum, philtrum, and menton, and document left-right differences in facial width, orbital level, and alar base position. 1
• Note presence of dysmorphic features or distinctive facial characteristics unusual for the family. 1

Follow-Up Monitoring Strategy

Close monitoring of progression is essential, as conditions like hemifacial microsomia demonstrate increasing asymmetry with growth, with angular measurements of facial planes progressively worsening from deciduous through permanent dentition. 1, 7

Repeat imaging may be necessary if symptoms progress or change, and families should understand that clinical changes including regression of motor skills, loss of strength, or concerns with respiration or swallowing should prompt urgent reevaluation. 3