Signs of Bell’s Palsy and How It Difffers from a Stroke

Bell’s palsy is a sudden paralysis of one side of the face that is often mistaken for a stroke. It causes anxiety and panic for both the patient and their loved ones, but unlike a stroke the consequences of Bell’s palsy is almost never fatal. Most cases of Bell’s palsy recovers completely and even without treatment. Symptoms typically ease within a few weeks from the time it starts but sometimes can take as much as 6 months to resolve completely. In some rare cases Bell’s palsy may recur but for the vast majority of patients they never experience it again.

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Differences between Bell’s Palsy vs Stroke

Both Bell’s palsy and a stroke are nerve-related problems. But Bell’s palsy is isolated to the facial nerve whereas a stroke affects the brain from where the facial nerve arises. While the the facial symptoms of Bell’s palsy and a stroke may be similar, the nature of the two conditions are very different.

Facial Nerve

In a stroke, the blood supply to the brain is interrupted in some way. It may either be due to a blockage in the arteries to the brain due to a blood clot (embolic stroke) or rupture of blood vessels (hemorrhagic stroke). It ultimately leads to ischemia (inflammation from oxygen deprivation) and death of portions of brain tissue. While there may be some degree of recovery in some stroke cases, dead brain tissue will never recover.

In Bell’s palsy the facial nerve specifically is affected. The exact reason is unknown but it seems to be due to nerve inflammation. There appears to be a link to certain infections caused by these viruses:

  • Herpes simplex
  • Herpes zoster
  • Cytomegalovirus
  • Rubella
  • Mumps
  • Coxsackievirus
  • Influenza
  • Adenovirus

Sudden Onset Symptoms

The symptoms of a stroke and Bell’s palsy arises suddenly. However, with most cases of a stroke there is often a warning for months or years before the event occurs. There are frequent episodes of “ministrokes” known as transient ischemic attacks (TIAs) where the symptoms similar to a stroke arise and then resolves. Eventually a stroke occurs. But some people never experience these mini-strokes and problems are only identified when the stroke occurs.

Bell’s palsy symptoms tend to develop over a slight longer duration than stroke symptoms. But this is largely dependent on individuals cases. Bell’s palsy symptoms develops over hours and days in comparison to the sudden stroke symptoms that may arise and progress within minutes or hours. Typically the Bell’s palsy symptoms peak within 48 hours and can progress over as long as 7 to 10 days. Apart from a stroke, many patients with Bell’s palsy also fear that it is a nerve or brain tumor but tumor-related symptoms develop gradually over a long period of time.

Bell's palsy

Picture of a Bell’s palsy patient attempting to smile. The right side of the face (left on the picture) is affected. Image sourced from Wikimedia Commons.

Weakness or Paralysis of the Face

The characteristic symptom of Bell’s palsy is weakness or even paralysis of the facial muscles. It usually affects one side of the face (unilateral), similar to a stroke. Both the upper and lower half of the face is affected. In rare cases both sides of the face may be affected. Initially this may be noticed as an inability to close the eyelids fully on one side or a slightly ‘fallen’ smile on the affected side. But as the symptom progresses, the face appears to be drooping on one side. This facial drooping is a result of the facial muscles not being able to contract as it normally would.

Pain In or Behind Ear

Ear pain is another common symptom of Bell’s palsy that is uncommon in a stroke. This pain may be felt in the ear, behind it and is sometimes also described as pain around the jaw. Eye pain may also be experienced as an early symptom. Half of all patients with Bell’s palsy will experience pain behind the ear. Usually it occurs simultaneously with the muscle weakening or paralysis of the face. But in about 1 out of 4 cases the ear pain may precede the onset of weakness and paralysis by 2 to 3 days.

Heightened Sensitivity to Sound

An abnormal sensitivity to sound (hyperacusis) is another symptom that is commonly seen in Bell’s palsy and may also occur in a stroke. It tends to occur on the same side as the weakness or paralysis. Hyperacusis is a result of the stapedius muscle becoming weakened. This is a tiny muscle (the smallest in the human body) that prevents the middle ear bone, the stapes, from vibrating excessively. When paralyzed the uncontrolled vibration of the stapes as a result of sound waves causes sound to be perceived louder than normal.

Impaired Ability to Taste

About 80% of patients with Bell’s palsy will experienced an impaired sense of taste (hypogeusia). However, it often goes unnoticed in most patients as the taste disturbance only affects one side of the tongue. The normal sense of taste on the other side may therefore make up for it and therefore this symptom goes unnoticed. In terms of prognosis, if the taste sensation returns to normal quickly then this is a good sign that the Bell’s palsy symptoms will resolve completely in due course.

Change in Tears and Saliva

Alterations in tearing and salivation are other common symptoms in Bell’s palsy. Initially patient’s experience reduced tear output but later in the condition there is excessive tearing when chewing. Excessive salivation on the affected side is another common symptom. It is often noticed as drooling since the dropping of the face affects the ability to slow the lips fully. Abnormalities in salivation and tearing is not unique to Bell’s palsy and may be seen in several other neurological conditions including a stroke or brain tumor.

Eye and Eyelid Problems

There are a number of eye and eyelid symptoms that occurs with Bell’s palsy. Eye pain and problems with tearing are the main eye symptoms. Some complications arise with the inability to close the eyelid completely and reduced tear secretion among other eye symptoms. These complications can be very severe and may occur even months after the first symptom’s of Bell’s palsy arises. It can affect vision and often many patients with Bell’s palsy will report blurring of the vision, similar to a stroke.

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