There are 12 pairs of cranial nerves. They are located in the head also called the cranium, or skull. The cranial nerves are those that arise directly from your brain or brainstem and often affect areas like the face and eyes. The cranial nerves control such functions as vision, hearing, facial movement and the actions of some of the organs in the head, chest, and abdomen.
Cranial neuropathy is when one or more of these nerves becomes injured, or damaged.
Cause of cranial Neuropathy
Damage to these nerves can occur from many causes, with a common one being diabetes. Cranial neuropathy is a problem that is usually caused by other medical conditions as well as trauma. (See Causes of Neuropathy)
In some cases, cranial neuropathy symptoms clear up within a few months.
Cranial neuropathy can result in a wide range of symptoms depending on which nerve is damaged.
· Abnormal functioning of the area it goes to
- · Sight
- · Hearing
- · Taste
- · Smell
- · Swallowing
- · Facial movement
- · Regulation of certain glands
- · Automatic functioning of chest and abdominal organs such as the heart and stomach.
One of the most common cranial neuropathies is damage to the seventh cranial nerve, called the facial nerve. This can cause facial pain focused near one of the eyes and paralysis of the eye muscles. Other problems can also occur including facial tics, twitches, spasms.
It can cause a complication called trigeminal neuralgia resulting in severe facial pain. Bell’s palsy is the condition which can occur when the facial nerve is affected.
Cranial nerves are also involved with motor control, instructing the muscles to move. Damage can result in not allowing someone to smile or wink, the eye to track moving objects, or the eye to focus.
Types of Cranial Neuropathy and the symptoms it creates
· Olfactory (first nerve) Loss or disturbance in the sense of smell.
· Optic (second nerve) Can cause blindness
· Oculomotor (third nerve) Drooping of the eyelid, eyeball moves outward, dilation of the pupil, double vision. These symptoms occur because the third cranial nerve is affected, and it helps to manage the muscles that move the eye.
· Throclear (fourth nerve) Rotation of eyeball upward and outward, double vision
· Trigeminal (fifth nerve) Sensory root – Pain or loss of sensation in the face, forehead, temple and eyes. Motor root – effecting the jaw, trouble chewing.
· Abducens (sixth nerve) Deviation of the eyes outward; double vision
· Facial (seventh nerve) Paralysis of all the muscles in one side of the face, inability to wrinkle the forehead, close the eye, whistle, deviation of the mouth.
· Vestibulococlear (eighth nerve) Deafness or ringing in the ears, dizziness, nausea and vomiting; Reeling.
· Glossopharyngeal (ninth nerve) Disturbance of taste; Difficulty in swallowing.
· Vagus (tenth nerve) Hoarseness and difficulty swallowing and talking.
This nerve also regulates the heart, blood vessels and digestion resulting in irregular heart beat and lowered blood pressure. It regulates the stomach telling it to move food through the digestive system, thus damage can result in decreased digestion and thus nausea, bloating and vomiting.
· Spinal Accessory (eleventh) Dropping of the shoulder; inability to rotate the head away from affected area.
· Hypoglossal (twelfth) Paralysis of one side of the tongue; deviation of tongue toward paralyzed side; thick speech.
Some of the Named Conditions of the Cranial Nerves
· Bell’s palsy. The facial nerve is affected. It can cause drooping of part of the face. It is believed to be caused by a virus that causes swelling, and then puts pressure (compression) on the facial nerve. It usually only affects one side of the face. See Compression Neuropathy
· Microvascular cranial nerve palsy. This condition affects the nerves in the eye. It is most common in people who are diabetic and in those who have high blood pressure. Its can cause double vision and other problems with eyesight.
· Third nerve palsy (oculomotor nerve) Third nerve palsy can cause an eyelid to sag and droop. It can cause difficulty moving the eye, and a pupil can be bigger than normal. It can cause double vision. It can be caused by an injury to the head or an infection. An aneurysm or brain tumor may also cause damage to this nerve.
· Fourth nerve palsy (throclear nerve) it is also called superior oblique palsy. It affects the muscle that is controlled by the fourth cranial nerve. It can cause the eye (or eyes) to turn abnormally and sometimes creates double vision. An injury to the head, or a stroke or tumor can also cause this condition.
· Sixth nerve palsy (abducans nerve) also called cranial nerve VI palsy; this nerve can be damaged by an infection, a stroke or tumor, creating increased pressure in the brain. Damage to the sixth cranial nerve can cause abnormal movement of the eye and double vision.
It is common to have more than one cranial nerve damaged.
Cranial neuropathy like other neuropathy can have symptoms that range from electrical shock, spasms, pain, or numbness in the area it controls and when a motor nerve is damaged – weakness and even paralysis.
What can be done?
Cranial neuropathy is damage to the cranial nerves. There are treatments for nerve damage or Neuropathy
You can read more about Neuropathy and its treatments
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