Facial palsy refers to the neurological syndrome of facial paralysis. It can result from a broad range of physiological insults to the facial nerve or its central nervous system origins. The most common causes of this is Bell palsy.
While facial palsy refers to the clinical presentation of facial paralysis and associated symptoms of facial nerve compromise it can sometimes be used interchangeably with facial nerve palsy which refers specifically to paralysis caused by a lesion in the facial nerve.
The distinction is important as facial nerve palsy implies almost an exclusively lower motor neurone cause of facial paralysis while the term facial palsy can include upper motor neurone lesions as well.
The facial nerve provides innervation to the facial muscles, middle ear, tongue, salivary and lacrimal glands. Accordingly signs and symptoms of facial nerve palsy include:
- dropping mouth
- loss of ipsilateral eye closure
- altered or reduced sense of taste
- dry mouth and/or eyes
- mild dysarthria
An important clinical discriminator between upper and lower motor neuron presentations of facial nerve palsy is that in the former there is sparing of the ipsilateral forehead muscles which allow patients to ipsilaterally wrinkle the forehead, raise the eyebrow, and completely close the eye. This finding is important in trying to localise the lesion and evaluating possible underlying causes.
The palsy can be complete or partial with the later carrying a better chance of full recovery. In partial paralysis the lower facial muscles are more prominently affected while loss of taste and sensation to the anterior 2/3 of the tongue occurs more frequently in complete lesions. The House-Brackmann grading system is used to score the severity of presenting facial nerve palsy to help guide treatment and follow up.
As above, the pathophysiology of facial nerve palsy depends on the underlying disease and can include all variety of causes summarised in the surgical sieve. Traditionally the preservation of forehead muscles in upper motor neurone lesions has been thought to be due the bilateral innervation of upper facial muscles by the cerebral cortices. However, this may not be supported by the literature 4.
Upper motor neuron causes
Lower motor neuron causes
- local anaesthetic from dental surgery
- skull base fracture (e.g. temporal bone)
- post-acupuncture haematoma
- if bilateral consider Guillain-Barre or Lyme disease
- if recurrent consider lymphoma, sarcoidosis or Lyme disease
- in children particularly consider Lyme disease and otitis media
- 1. Hohman MH, Hadlock TA. Etiology, diagnosis, and management of facial palsy: 2000 patients at a facial nerve center. Laryngoscope. 2014;124 (7): E283-93. doi:10.1002/lary.24542 - Pubmed citation
- 2. Linder TE, Abdelkafy W, Cavero-Vanek S. The management of peripheral facial nerve palsy: "paresis" versus "paralysis" and sources of ambiguity in study designs. Otol. Neurotol. 2010;31 (2): 319-27. doi:10.1097/MAO.0b013e3181cabd90 - Pubmed citation
- 3. Lee HY, Park MS, Byun JY et-al. Agreement between the Facial Nerve Grading System 2.0 and the House-Brackmann Grading System in Patients with Bell Palsy. Clin Exp Otorhinolaryngol. 2013;6 (3): 135-9. doi:10.3342/ceo.2013.6.3.135 - Free text at pubmed - Pubmed citation
- 4. Mahadevappa K, Vora A, Graham A et-al. Facial paralysis: a critical review of accepted explanation. Med. Hypotheses. 2010;74 (3): 508-9. doi:10.1016/j.mehy.2009.10.010 - Pubmed citation