From the Guidelines
Facial nerve stroke syndromes are neurological conditions that affect the facial nerve (cranial nerve VII) due to interruption of blood supply to specific areas of the brainstem, resulting in central or peripheral facial palsy, with the most common being central facial palsy, which occurs when a stroke affects the facial motor cortex or its descending pathways, and peripheral facial nerve strokes, which can occur when there is infarction of the facial nucleus in the pons or the nerve itself, as described in the 2022 update of the ACR Appropriateness Criteria for cranial neuropathy 1.
Key Characteristics of Facial Nerve Stroke Syndromes
- Central facial palsy: weakness of the lower face on the side opposite to the brain lesion, sparing the forehead muscles due to bilateral cortical innervation
- Peripheral facial nerve strokes: complete facial weakness on the same side as the lesion, including the forehead, due to infarction of the facial nucleus in the pons or the nerve itself
- Presentation: sudden onset of facial asymmetry, difficulty closing the eye, drooling, and speech difficulties
- Treatment: managing the underlying stroke with antithrombotics, controlling risk factors, and providing supportive care, including eye protection and physical therapy
Diagnostic Considerations
- MRI head without and with IV contrast or MRI orbits, face, and neck without and with IV contrast may be appropriate for initial imaging of patients with unilateral isolated weakness of the facial expression, paralysis of the facial expression, hemifacial spasm, or Bell palsy (facial nerve, CN VII) 1
- The facial nerve (CN VII) contains branchial motor, visceral motor, general sensory, and special sensory functions, and its intracranial course includes pontine, cisternal, and intratemporal segments, making it susceptible to various pathologies, including infarction, vascular malformations, tumors, and multiple sclerosis 1
Clinical Implications
- The distinction between central and peripheral patterns is crucial for localizing the lesion and determining appropriate management strategies
- Facial nerve palsy can present with facial droop, pain around the jaw or ear, hyperacusis, tinnitus, reduced taste, and decreased lacrimation or salivation, and most patients with Bell’s palsy experience complete recovery of function by 6 months, which can be hastened with steroids 1
From the Research
Facial Nerve Stroke Syndromes
The facial nerve, also known as cranial nerve VII, can be affected by stroke, leading to various syndromes. Some of the key points related to facial nerve stroke syndromes include:
- Central facial paresis (CFP) is a major symptom of stroke, which can result in motor and non-motor disabilities 2
- CFP can have a significant impact on a patient's quality of life, and therapy focusing on specific facial muscles can be an effective part of post-stroke rehabilitation 2
- Facial nerve stimulation has been explored as a potential treatment for ischemic stroke, as it can rapidly dilate cerebral arteries and increase cerebral blood flow 3
- Bell's palsy, a condition characterized by acute unilateral facial nerve paralysis, can be distinguished from stroke through careful evaluation and diagnostic testing 4, 5
Causes and Treatment
The causes of facial nerve paralysis can be varied, and understanding the underlying cause is crucial for effective treatment. Some key points related to causes and treatment include:
- Bell's palsy is the most common cause of acute unilateral facial nerve paralysis, and its treatment may involve antiviral medication, corticosteroid therapy, and other interventions 4, 6
- Antiviral combined with steroid treatment has been shown to be effective in treating facial paralysis, particularly in cases of Bell's palsy 6
- A careful patient evaluation and appropriate diagnostic testing are essential for guiding clinicians and improving outcomes in cases of facial nerve paralysis 5