Acute peripheral facial paralysis caused by tegmental pontine infarction

Area of Science:

• Neurology
• Neuroradiology

Background:

• Peripheral facial paralysis, characterized by unilateral mouth drooping and lagophthalmos, is commonly attributed to Bell's palsy or Ramsay-Hunt syndrome.
• Pontine infarction affecting the facial nucleus is a rare cause of lower motor neuron facial paralysis.

Observation:

• A man in his 50s presented with unilateral peripheral facial paralysis.
• Initial diffusion-weighted imaging (DWI) was unremarkable, leading to management for hypertensive encephalopathy or Bell's palsy.
• On day 3, diagnosis shifted to left pontine infarction, with suspected left anterior inferior cerebellar artery infarction.

Findings:

• Early-onset or posterior circulation infarcts, including pontine infarctions, can yield false-negative results on DWI.
• Re-evaluation of imaging is crucial in cases with persistent or evolving symptoms suggestive of stroke.

Implications:

• This case highlights the potential for DWI to miss early pontine infarcts presenting as facial paralysis.
• Clinicians should consider re-examining imaging in suspected stroke cases with initially negative DWI, especially in the posterior circulation.
• Timely diagnosis of pontine infarction is critical for appropriate stroke management and improved patient outcomes.