From the Guidelines
Facial nerve stroke syndromes, also known as central facial paralysis, occur when a stroke affects the facial nerve pathway in the brain, resulting in a unilateral lower facial weakness on the side opposite to the brain lesion, with the forehead muscles typically spared due to bilateral innervation from the cortex. The most common presentation is a unilateral lower facial weakness on the side opposite to the brain lesion, which occurs because the facial nerve fibers controlling the lower face cross in the brainstem, while those controlling the forehead do not 1. Management primarily focuses on treating the underlying stroke with appropriate measures like thrombolysis if eligible, followed by antiplatelet therapy or anticoagulation if indicated. Some key points to consider in the management of facial nerve stroke syndromes include:
- Physical therapy and facial exercises should begin early to maintain muscle tone and prevent contractures
- Speech therapy may be necessary if speech is affected
- Prognosis varies depending on stroke severity, with many patients experiencing some degree of spontaneous recovery within 3-6 months
- Eye protection with artificial tears or lubricants may be needed if eye closure is affected
- Unlike Bell's palsy, corticosteroids are not typically indicated specifically for the facial weakness in stroke 1. It is essential to differentiate facial nerve stroke syndromes from other causes of facial weakness, such as Bell's palsy, which is a diagnosis of exclusion requiring the careful elimination of other causes of facial paresis or paralysis 1.
From the Research
Facial Nerve Stroke Syndromes
The facial nerve, also known as cranial nerve VII, can be affected by various stroke syndromes. One of the most common conditions is Bell's palsy, which is characterized by an acute onset of unilateral, lower motor neuron weakness of the facial nerve in the absence of an identifiable cause 2.
Characteristics of Bell's Palsy
Bell's palsy is often accompanied by facial pain or paraesthesia, altered taste, and intolerance to loud noise, in addition to facial droop 3. The lifetime risk of developing Bell's palsy is 1 in 60, and it is more common in pregnancy and diabetes mellitus 3.
Treatment Options
Corticosteroids are the mainstay of treatment for Bell's palsy and should be initiated within 72 hours of symptom onset 2, 4. Antiviral therapy in combination with corticosteroid therapy may confer a small benefit, but the evidence is not conclusive 2, 5. The optimal treatment approach may involve a personalized approach, taking into account factors such as age, electroneurography (ENoG) and electromyography (EMG) results, and comorbid conditions 5.
Prognosis and Outcome
The outcome of Bell's palsy treatment can be influenced by various factors, including the timing of treatment initiation, patient age, and the presence of concurrent chronic medical illnesses 5, 6. Patients who receive steroid monotherapy within 72 hours of symptom onset tend to have better recovery rates 5. However, combined therapy with antivirals may be beneficial for patients with more severe disease 5, 6.
Key Points
- Bell's palsy is a common condition characterized by acute onset of unilateral, lower motor neuron weakness of the facial nerve
- Corticosteroids are the mainstay of treatment and should be initiated within 72 hours of symptom onset
- Antiviral therapy may confer a small benefit, but the evidence is not conclusive
- A personalized approach to treatment, taking into account individual patient factors, may be beneficial
- The outcome of treatment can be influenced by various factors, including timing of treatment initiation, patient age, and presence of concurrent chronic medical illnesses