Cranial neuropathy occurs when there is damage to the cranial nerves in the brain or brain stem. Depending on the affected cranial nerve, people may experience different symptoms, such as weakness on one side of the face.

The human brain has 12 pairs of cranial nerves that are responsible for processing sensory information or movement. Damage to any part of the cranial nerves can affect various functions — for example, third nerve palsy can lead to changes in eye movement or vision.

Treatment for cranial neuropathy can vary and may include medications, surgery, and complementary therapies. A doctor can advise on the best treatment option.

Keep reading to learn more about cranial neuropathy, including the different types, what symptoms they may cause, and how doctors might diagnose and treat the condition.

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Cranial neuropathy most commonly affects cranial nerve III, the oculomotor nerve. Doctors refer to this condition as third nerve palsy. Cranial nerve III branches out to connect the pupil and lens, the upper eyelid, and the muscles surrounding the eye. Therefore, this type of neuropathy can affect vision.

Other cranial neuropathies include:

  • Bell’s palsy
  • fourth nerve palsy
  • sixth nerve palsy

Multiple cranial neuropathies

A person may have damage to more than one cranial nerve, resulting in multiple cranial neuropathies.

Microvascular cranial nerve palsy is a neuropathy type that can affect one or more cranial nerves. It can lead to changes in vision.

The specific causes of cranial neuropathy can depend on the type someone has. For example, in microvascular cranial nerve palsy, a lack of blood flow to nerves in the brain typically leads to neuropathy.

Trigeminal neuralgia occurs when cranial nerve V becomes irritated or damaged. Damage to this nerve usually results from trauma or injury or from a blood vessel pushing against the nerve.

Experts have identified several causes of third nerve palsy, including:

  • blood clots
  • trauma
  • bleeding

Dysfunction in cranial nerve III can sometimes occur if a tumor is growing on or near the nerve.

Still, in some cases, the cause of neuropathy is unknown. For example, doctors do not yet know the exact cause of Bell’s palsy.

Symptoms can depend on the specific cranial nerve the neuropathy affects. Some nerves have specific functions such as vision, taste, and hearing. Therefore, damage can lead to a loss of these functions. For example, when the optic nerve is damaged, people may experience lifelong vision impairments.

When nerves become damaged, they typically signal pain, numbness, or weakness.

Cranial nerve VII, which connects the brain to the muscles of the face, becomes damaged in Bell’s palsy. This leads to the following symptoms:

  • drooping of the eyebrow and mouth
  • drooling on one side of the mouth
  • sudden weakness or paralysis on one side of the face
  • trouble closing the eyelid on the affected side

The symptoms of cranial neuropathy can vary greatly from person to person.

As a first step in diagnosing cranial neuropathy, a doctor will take a person’s medical history. Then, depending on the type of cranial neuropathy the doctor suspects, other tests become necessary.

A physical examination is another way to assess neuropathy symptoms. For example, for Bell’s palsy, doctors will examine upper and lower facial muscles for weakness.

Doctors may order the following tests:

  • blood pressure and blood sugar checks
  • complete blood counts
  • spinal tap
  • eye examinations — particularly if they suspect third nerve palsy
  • imaging tests

Some of these tests can help determine whether the neuropathy has an underlying cause. Neurologists may use other specialized tests in diagnosis, such as electromyography, which evaluates muscle electrical activity.

Imaging

Medical imaging techniques and a complete medical history can help diagnose and monitor cranial neuropathies. Various imaging techniques can be helpful, including CT and MRI scans. Both types can detect nerve damage.

The choice of the most appropriate type of medical imaging depends on many factors, including:

  • the affected cranial nerve
  • the signs and symptoms of neuropathy a person has
  • specific characteristics of the person

Treatments for cranial neuropathy can vary depending on the specific nerve affected and the person’s symptoms.

Medications

For cranial neuropathy that causes severe pain, doctors may prescribe pain medications such as antiseizure or antidepressant medications.

Examples of drugs that doctors prescribe for pain from trigeminal neuralgia include:

  • amitriptyline
  • carbamazepine (Tegretol)
  • topiramate (Topamax)
  • gabapentin (Neurontin)
  • nortriptyline (Pamelor)

Depending on the severity of the pain, people with cranial neuropathy may use nonsteroidal anti-inflammatory drugs, acetaminophen (Tylenol), or opioids.

Doctors may prescribe steroids to reduce inflammation and swelling around a nerve. For example, a combination of antiviral drugs and steroids can sometimes be effective for treating Bell’s palsy.

Surgery

Sometimes the only option for treating cranial neuropathy is surgery.

Surgery can be reconstructive or cosmetic if cranial neuropathies cause damage that affects a person’s appearance. Doctors may recommend surgery for some people with Bell’s palsy to help them fully close their eyes or to repair a crooked smile.

Complementary treatments

For trigeminal neuralgia, experts may recommend complementary treatments such as:

Other complementary therapies may be beneficial for other types of neuropathy. For example, doctors may recommend the following for someone living with Bell’s palsy:

Preventing cranial neuropathy can be challenging because the causes are not always within a person’s control. For example, people cannot control where a tumor or blood clot develops.

Diabetes is a cause of peripheral neuropathy. A person may be able to prevent type 2 diabetes by maintaining a moderate weight, eating healthy, and exercising regularly.

Generally, following guidelines for a safe and healthy lifestyle can help reduce the risk of developing cranial neuropathy.

Vision changes, sudden pain, and muscle weakness are symptoms of certain cranial neuropathies. Anyone with these symptoms should consult a doctor immediately, as they might signal a severe medical condition such as a stroke.

Also, people who have a cranial neuropathy diagnosis may want to make a plan with their doctor about when to call for help — for example, if symptoms worsen or newer ones develop.

Cranial neuropathies include many conditions that affect any part of the 12 cranial nerve pairs in the brain. General symptoms may include pain, weakness, and loss of function. However, each type of cranial neuropathy has specific symptoms.

People concerned about symptoms of cranial neuropathy should speak with a doctor immediately. Some symptoms of cranial neuropathy are similar to those of a stroke or other severe conditions that require emergency medical attention.