Causes and treatment of peripheral facial palsy

1. Big picture

Peripheral facial palsy means a lower motor neuron lesion of the facial nerve/facial nucleus, causing weakness of the entire ipsilateral half of the face: forehead, eye closure, and mouth.

For the exam, the key is to answer three things quickly:

1. Is it central or peripheral? Peripheral = forehead involved. Central = forehead usually spared.

2. Where is the facial nerve lesion? Use associated symptoms: dry eye, hyperacusis, taste loss, hearing/vertigo, ear vesicles.

3. Is it Bell’s palsy or a dangerous secondary cause? Bell’s palsy is common, but never miss stroke, brainstem lesion, Ramsay Hunt syndrome, Lyme disease, Guillain-Barré syndrome, tumor, trauma, or otitis/mastoiditis.