What are Cranial Neuropathies: Causes, Types, Symptoms, Treatment, Prevention

Nerves are present throughout the body and power our entire body. Nerves are responsible for transmitting information back and forth from the brain to all over the body. However, these nerves can be damaged due to any illness or injury. Neuropathy is a condition where there is nerve damage leading to impaired ability of the patient to feel and move. The exact manner in which the body is affected and the movement is affected depends on the location of the damaged nerves. When cranial nerves, which originate directly from the brain or brainstem, are damaged or affected, then this condition is termed as cranial neuropathy.

The cranial neuropathy often affects areas like eyes and face. Different types of cranial neuropathies are:

Bell’s Palsy: This is the type of cranial neuropathy which affects the 7th cranial nerve (facial nerve).

Third Nerve Palsy: This type of cranial neuropathy affects the 3rd cranial nerve, which is responsible for managing the muscle which controls eye movement.

Microvascular Cranial Nerve Palsy: This type of cranial neuropathy affects the nerves in the eye and is more commonly seen in patients suffering from hypertension or diabetes.

Fourth Nerve Palsy: This type of cranial neuropathy is also termed as superior oblique palsy, which affects the superior oblique muscle. The function of this muscle is converging the eyes, such as when trying to look at the tip of the nose.

Sixth Nerve Palsy: Also known as abducens palsy, which affects the 6th cranial nerve, the function of which is controlling the eye movement.

Multiple Cranial Neuropathies: If there are many cranial nerves affected, then it is termed as multiple cranial neuropathies (MCN).

• Viral infection such as seen in Bell’s palsy can cause Cranial Neuropathy.
• High blood pressure can cause Cranial Neuropathy, such as seen in Microvascular cranial nerve palsy.
• An injury to the head can also cause Cranial Neuropathy such as seen in fourth nerve palsy.
• Cranial Neuropathy can be congenital, such as seen in third nerve palsy.
• Migraine and diabetes are other causes of Cranial Neuropathy.
• Brain tumor or brain aneurysm or any disorder which affects the brain can cause Cranial Neuropathy, such as third nerve palsy.
• The 6th cranial nerve can get damaged by stroke, infection or tumor.
• Fourth nerve palsy is commonly a congenital birth defect; however, stroke, head injury or tumor can also cause 4th nerve palsy.
• Increased pressure in the brain can also cause cranial neuropathy.
• Vitamin B12 deficiency is also thought to cause cranial neuropathy.

Symptoms of cranial neuropathy depend on its type, the location and the damage to the cranial nerves. Common symptoms seen in cranial neuropathy are: Pain, numbness, tingling sensation, skin which feels sensitive to touch, paralyzed or weak muscles.

Different types of cranial neuropathies produce different symptoms such as:

• Microvascular cranial nerve palsy causes symptoms, such as double vision and other eye sight problems.
• Bell’s palsy causes symptoms, such as drooping of a part of the face and usually affects one side of the face.
• Third nerve palsy produces symptoms, such as dropping and sagging of the eyelid, double vision, a bigger than normal pupil and difficulty in moving the eye.
• Fourth nerve palsy causes symptoms, such as abnormal turning of the eye or eyes. It can also cause double vision.
• Sixth nerve palsy produces symptoms, such as double vision and abnormal eye movements.

Different types of tests are done to diagnose cranial neuropathy such as:

• Neurological exam is done to test the patient’s reflexes, sensation, mental status and balance.
• CT or MRI scans are imaging tests, which help in seeing a clear picture of the brain.
• Nerve conduction velocity tests are done to find out the cause of the nerve damage and where the damage is located on the nerve.
• Electromyography (EMG) is a test which measures the muscles’ electrical activity at work and at rest.
• Biopsy of the nerves and skin are done to find out the severity of the damage to the nerves.
• Angiography is done to evaluate the heart and blood vessels.

The aim of treatment of cranial neuropathy is to treat the underlying condition, which is causing it, such as infection, high blood pressure or diabetes. Some types of cranial neuropathies can get better with time and may not need any treatment. In some cranial neuropathies, medicines are used such as for treating infection, to reduce the swelling or to relieve pain caused by cranial neuropathy. Surgery may be needed for some types of cranial neuropathies. Whereas, the nerve damage in some cranial neuropathies cannot be treated.

Patients with cranial neuropathy should follow a healthy and nutritious diet, which consists of fresh vegetables and fruits. Patient should also quit smoking and restrict alcohol consumption. Taking vitamin B12 supplements are also beneficial in managing the symptoms of cranial neuropathies.

As mentioned before, diagnosis and treatment of underlying health conditions, which are causing cranial neuropathy is important. Treating the common causes of cranial neuropathy, such as hypertension, infections and diabetes helps in managing and treating the cranial neuropathy.

It is not always possible to prevent cranial neuropathy. However, controlling the common causes helps in cutting down the risk of developing cranial neuropathy. Patient should concentrate on reducing the risk factors for head injury, stroke, see to it that his/her diabetes and hypertension is under control in order to prevent cranial neuropathy.

Cranial neuropathies are usually not a life threatening condition and can improve on their own with time. However, cranial neuropathies can affect the patient’s quality of life. It is important to manage and control the possible causes of cranial neuropathy in order to manage and control the symptoms of cranial neuropathy. This is the best plan in living and working with cranial neuropathy. If the symptoms of cranial neuropathy do not resolve on their own, then occupational therapy, physical therapy or other such options can help in managing the symptoms and help you get through your day to day activities. Surgery is needed if cranial neuropathy is badly affecting the patient’s quality of life.

• Damage to one or more cranial nerves cause cranial neuropathies.
• Cranial nerves originate directly from the brain and are responsible for sensation and movement in the face and eyes.
• Common symptoms of cranial neuropathy include changes in vision, weakness or loss of sensation in an area of the face.
• The causes of cranial neuropathies consist of infection, hypertension, poorly controlled diabetes, head injuries, brain tumors and strokes.
• There are some cranial neuropathies, which resolve on their own without any treatment; whereas, some cranial neuropathies are permanent.
• The symptoms of cranial neuropathies can be controlled or managed by controlling hypertension and diabetes or other underlying causes of cranial neuropathy.
• Treatment of cranial neuropathies consists of treating the underlying cause and includes medicines, surgery and other treatment options, such as occupational therapy and physiotherapy.