Bell's palsy vs. stroke: What's the difference?

Bell's palsy and stroke symptoms can sometimes resemble each other, but the two couldn't be more different. As a paramedic, it's important to be able to differentiate between the two while assessing a patient.

[Read next: When a stroke is not a stroke: A case study]

Here's a breakdown of differences in Bell's palsy and stroke symptoms and prehospital care differences.

What is Bell's palsy?

Bell's palsy, according to the National Institute of Neurological Disorders and Stroke, is a form of temporary facial paralysis. When a patient is suffering from Bell's palsy, the facial nerve becomes disrupted and an interruption in messages to the brain results in facial weakness or paralysis.

The disorder, NINDS notes, isn't related to stroke. It is, however, the most common cause of facial paralysis. In rare cases, Bell's palsy can affect both sides of the face. Most often, it affects only one side of the face.

And for those who are wondering – Bell's palsy was named after Sir Charles Bell, a Scottish surgeon who made the connection to the condition.

What is a stroke?

A stroke, according to the American Stroke Association, occurs when a clot blocks a blood vessel that's carrying oxygen and nutrients to the brain. As a result, the brain can't get blood and oxygen and brain cells die.

There are two types of stroke:

1. Ischemic stroke: when a clot obstructs the flow of blood to the brain.

2. Hemorrhagic stroke: when a blood vessel ruptures, preventing blood flow to the brain.

A temporary clot causes transient ischemic attack (TIA), also known as a mini stroke.

Stroke, ASA notes, is the number five cause of death and leading cause of disability in the U.S.

Differences in symptoms

Symptoms of Bell's palsy vary depending on the case; they also range in severity from mild weakness to total paralysis. 

Stroke symptoms	Bell's palsy symptoms
Trouble walking, speaking and understanding	Twitching
Paralysis or numbness of the face, arm or leg	Weakness or paralysis on one side of the face; in rare cases, both sides of the face
Problems with coordination, stiff muscles, overactive reflexes or paralysis of one side of the body	Drooping of the eyelid and corner of the mouth
Fatigue, lightheadedness or vertigo	Dryness of the eye or mouth
Blurred vision, double vision, sudden visual loss or temporary loss of vision in one eye	Impairment of taste
Pins and needles or reduced sensation of touch	Excessive tearing in one eye
Difficulty swallowing	Pain or discomfort around the jaw and behind the ear
Headache	Ringing in one or both ears
Rapid involuntary eye movement	Headache, dizziness
Mental confusion	Difficulty eating or drinking

Prehospital care treatment of Bell's palsy vs. stroke

Once you've made your assessment on whether or not your patient is suffering from Bell's palsy or stroke, your next step is to provide proper prehospital treatment.

Prehospital treatment for stroke and Bell's palsy victims includes:

Stroke victims	Bell's palsy victims
Assess the airway, breathing and circulation	Assess the airway, breathing and circulation
Determine the time of onset of symptoms	Determine the time of onset of symptoms
Perform a neurological exam	Perform a neurological exam
Check blood sugar	Focus your exam on the forehead
Establish an IV route, but don't give large amounts of fluid	Ask about recent viral infection
Establish a baseline 12-lead ECG	Ask about recent immunization
Reassure the patient, who is often times very anxious	Transport the patient as soon as possible
Transport the patient as soon as possible	Reassure the patient, who is often times very anxious
Give the receiving ED a head's up	Give the receiving ED a head's up

Additionally, the COWS mnemonic can be used for examining a possible Bell's palsy patient:

• C: Close eyes
• O: Open eyes
• W: Wrinkle forehead
• S: Smile

And, if you're still unsure about a patient's assessment, ask your patient to raise their eyebrows. If a patient has Bell's palsy, their eyebrows will rise asymmetrically.

This article was originally posted Sept. 26, 2017. It has been updated.