What Are Cranial Nerve Injuries?
The entire body is powered by nerves. But an injury or a disease like diabetes can harm those nerves. Nerve damage or nerve injury is what causes neuropathy, a disease. The ability to feel and move is impacted. The location of the damaged nerves in the body determines exactly how the body and movement are affected. Cranial neuropathy occurs when nerves in the brain or brainstem are affected.
The nerves that come directly from the brain or brainstem are called cranial nerves. They frequently affect the eyes and face. Some of the different types of cranial neuropathies include the following -
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Bell Palsy - This condition occurs when the facial nerve (seventh cranial nerve) gets affected.
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Microvascular Cranial Nerve Palsy - One or more nerves, typically those that lead to the eye, are impacted by this condition. People who have diabetes and high blood pressure are more likely to experience it.
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Third Nerve Palsy - In this condition, the third cranial nerve is affected. The third cranial nerve manages the muscles that control eye movement and pupil size.
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Fourth Nerve Palsy - This condition is also termed superior oblique palsy. It affects the superior oblique muscle, which helps to converge the eyes (to look at the tip of the nose).
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Sixth Nerve Palsy - This condition is also termed cranial nerve VI or abducens palsy. The sixth cranial nerve gets affected, which is also responsible for controlling eye movement.
Multiple cranial neuropathies (MCN) are conditions in which multiple cranial nerves are affected.
What Causes Cranial Nerve Injury?
Cranial neuropathy or cranial nerve injury can develop due to many different reasons. These may include the following:
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Infections - Cranial nerves can be irritated by infections in the spinal fluid. The seventh nerve, for instance, is frequently affected by Lyme disease. However, it has the potential to harm any cranial nerve.
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Cancer - Cancer cells can damage one or more cranial nerves if they spread to the spinal fluid. Cranial nerves, which run through the skull, can sometimes be compressed by cancer.
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Head Trauma, Brain Swelling, or Tumor Causing Increased Intracranial Pressure - These conditions can injure cranial nerves. Certain headaches can also raise the intracranial pressure. Cranial nerves three, four, and six most often get affected.
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Congenital Cranial Neuropathies - These are nerve injuries that occur at the time of birth due to trauma or can occur before birth due to developmental problems or infection.
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Microvascular Cranial Nerve Palsy - This condition can occur in people with high blood pressure or other vascular risks, such as smoking or diabetes. As a result, the cranial nerves get injured due to poor blood supply. It most often affects cranial nerves three, four, and six.
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Autoimmune Abnormalities - These autoimmune abnormalities occur when the immune system attacks the body’s own cranial nerves. Examples of this include Guillain-Barré syndrome or lupus.
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Aneurysm - An aneurysm is a ballooning or weakened spot in an artery. This can put pressure on the nearby nerves. It most often affects cranial nerves three, four, and six.
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Inflammatory Disorders - These include sarcoidosis (growth of small collections of inflammatory cells in any body part) and multiple sclerosis (immune system attacks the protective covering of nerves).
What Are the Symptoms of Cranial Nerve Injury?
Different types of cranial nerve injury or neuropathy can result in different symptoms. They are based on the type of nerves that are damaged and their location. Generally, neuropathies can lead to the following symptoms -
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A tingling sensation.
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Pain.
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Numbness.
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Vision changes.
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Skin that feels sensitive to the touch.
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Weak or paralyzed muscles that may cause drooling or slurred speech.
Different types of cranial neuropathies may include some of the following symptoms -
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Part of the face may droop as a result of bell palsy. Most of the time, it only affects one side of the face.
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Double vision, droopy eyelids, and other vision issues can be caused by microvascular cranial nerve palsy.
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Third nerve palsy can result in an abnormally large pupil, double vision, difficulty moving the eye, and a sagging and drooping eyelid.
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The eye or both eyes turn abnormally due to fourth nerve palsy. Sometimes it causes the patient to see twice. They might have to tilt their heads while looking.
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Double vision and abnormal eye movement are both possible outcomes of sixth nerve palsy.
How Are Cranial Nerve Injuries Diagnosed?
A healthcare provider will often do various tests to diagnose a cranial nerve injury or neuropathy. Depending on the type of cranial nerve injury a healthcare provider suspects, the following tests may be needed -
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Nervous system examination to assess mental status, balance, and sensation.
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Infections and health conditions like diabetes can be detected through blood tests.
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Electromyography (EMG) determines the electrical activity of muscles when working and at rest.
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Computed tomography (CT) or magnetic resonance imaging (MRI) scans are imaging tests that let healthcare providers see the brain.
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Nerve conduction velocity tests help determine how and where the nerve is damaged.
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Skin and nerve biopsies to determine the severity of the damaged nerves.
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Hearing tests.
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To check for infection or inflammation in the spinal fluid, a spinal tap (lumbar puncture) is performed.
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Angiography is a special X-ray that takes pictures of the heart and blood vessels using contrast dye.
How Are Cranial Nerve Injuries Treated?
A nerve injury or cranial neuropathy could indicate a life-threatening situation. It should be evaluated right away by a healthcare professional. Without treatment, many cranial neuropathies will improve over time. Medicines can sometimes treat an infection, reduce nerve swelling, or alleviate pain caused by neuropathy. Surgery may be helpful in some cases and for some kinds of neuropathies. Sometimes, nerve damage cannot be fixed or treated.
However, it is critical to identify and treat any underlying medical conditions that may be causing the neuropathy. Neuropathy can be helped to be treated by treating common conditions like diabetes, high blood pressure, and infections. Neuropathy can also be managed by avoiding smoking, drinking too much, and eating healthy foods.
Can Cranial Neuropathies Be Prevented?
Cranial neuropathy cannot always be prevented. But controlling common causes can help to reduce the risk of developing neuropathy. Some preventive measures include -
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Reducing the risk factors for diabetes, stroke, and head injury.
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Managing diabetes well if the patient has the disease.
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Lowering blood pressure, if needed.
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Following a healthy lifestyle includes smoking cessation, regular exercise, maintaining a healthy weight, and eating a balanced diet.
Conclusion
Nerve injuries or cranial neuropathy are typically not dangerous. With time, they might get better on their own. But those who have the condition can find it bothersome. The best way to treat cranial neuropathy is to address the potential causes. Diabetes, high blood pressure, infections, and brain tumors are among these. Head injuries should also be avoided. The medical team may suggest physical therapy, occupational therapy, or other treatments for the symptoms if they do not improve on their own. If cranial neuropathy affects the quality of life, one should talk to a doctor about other options, like surgery.
