What is the difference between Bell's palsy and a cerebrovascular accident (CVA), also known as a stroke?

From the Guidelines

Bell's palsy and stroke are distinct conditions that require different treatment approaches, with Bell's palsy being a temporary facial paralysis and stroke being a life-threatening condition that requires immediate emergency treatment. Bell's palsy is a temporary facial paralysis resulting from inflammation of the facial nerve (cranial nerve VII), typically affecting one side of the face, and it usually develops suddenly and resolves within weeks to months 1. In contrast, a stroke occurs when blood flow to the brain is interrupted, causing brain cell death, and facial weakness from stroke is often accompanied by other neurological symptoms like arm/leg weakness, speech problems, or vision changes 1.

Key Differences

• Bell's palsy typically affects all facial muscles on one side, including the forehead, while stroke-related facial weakness usually spares forehead movement because of bilateral cortical innervation to the upper face 1.
• The sudden onset of unilateral facial paresis/paralysis and the absence of signs indicative of another underlying cause allow for the diagnosis of Bell's palsy 1.
• A comprehensive history and physical examination are essential to detect neurologic, otologic, oncologic, inflammatory, or infectious causes, and to rule out other conditions that may cause facial paralysis, such as stroke, brain tumors, or systemic diseases 1.

Treatment Approaches

• Treatment for Bell's palsy includes corticosteroids like prednisone (60-80mg daily for 5-7 days, then tapered) started within 72 hours of symptom onset to reduce inflammation and improve recovery, as well as eye protection with artificial tears and lubricating ointment to prevent corneal damage 1.
• Stroke requires immediate emergency treatment, potentially including clot-busting medications like tPA if administered within 3-4.5 hours of symptom onset, and a comprehensive evaluation to determine the underlying cause and to develop an appropriate treatment plan 1.

Importance of Early Diagnosis

• Early diagnosis and treatment of both conditions are crucial to improve outcomes and reduce the risk of complications, such as permanent facial paralysis or brain damage 1.
• Healthcare providers should be aware of the key distinguishing features between Bell's palsy and stroke to ensure prompt and accurate diagnosis and treatment, and to reduce the risk of misdiagnosis or delayed diagnosis 1.

From the Research

Bell's Palsy and Stroke: Key Differences

• Bell's palsy is the most common cause of acute unilateral facial nerve paralysis, whereas stroke is a condition that occurs when the blood supply to the brain is interrupted, leading to tissue damage and loss of brain function 2.
• The symptoms of Bell's palsy and stroke can be similar, but there are subtle differences between the two conditions, including the presence of facial weakness, drooping, and difficulty speaking or understanding speech 2.

Causes of Bell's Palsy

• The exact cause of Bell's palsy is not fully understood, but it is believed to be related to a viral infection, such as herpes simplex virus type 1 (HSV-1), which can cause inflammation and damage to the facial nerve 3, 4.
• Other studies have suggested that HSV-1 may be the etiological agent that causes Bell's palsy, and that antiviral medication may be beneficial in treating the condition 3, 4.

Diagnosis and Treatment of Bell's Palsy

• The diagnosis of Bell's palsy is typically made based on a physical examination and medical history, and may involve tests such as electromyography (EMG) or imaging studies like MRI or CT scans 2.
• Treatment for Bell's palsy may include antiviral medication, corticosteroid therapy, eye care, botulinum toxin type A injection, physiotherapy, surgery, and acupuncture, as well as psychological and emotional support to help manage anxiety and stress related to the condition 2, 3.

Relationship Between Bell's Palsy and Herpes Simplex Virus

• Several studies have investigated the relationship between Bell's palsy and herpes simplex virus, with some suggesting that HSV-1 may be the primary cause of the condition 4, 5, 6.
• However, other studies have found that the presence of HSV-1 genomic DNA in the geniculate ganglion does not necessarily explain the direct association with Bell's palsy, and that further research is needed to fully understand the relationship between the two 5.