Cranial nerve palsy can occur when pressure is put on the nerve or is not getting enough blood.
The cranial nerves are twelve pairs of nerves found in the brain, neck, and trunk: some of them affect sensations such as sight, hearing, and taste, while others control the muscles of the face and glands.
- Olfactory nerve
- Optic nerve
- Oculomotor nerve
- Trochlear nerve
- Trigeminal nerve
- Adductor nerve
- Facial nerve
- Vestibulocochlear nerve
- Glossopharyngeal nerve
- Vagus nerve
- Accessory nerve
- Hypoglossal nerve
A disorder affecting the cranial nerves can arise from damage or dysfunction in certain specific areas of the brain:
- the areas that control the cranial nerves
- the nerve fibers that connect the brain to the cranial nerves
Some of these disorders interfere with eye movement, which is controlled by 3 pairs of muscles: these muscles are controlled by the 3rd, 4th and 6th nerves. If even one of these nerves is damaged, the muscles can suffer paralysis: the severity of the damage depends on which nerve is affected.
Cranial Nerve Paralysis and Disorders: Causes and Symptoms
Disorders affecting the nerves of the brain can be caused by many different situations:
- Head trauma
- Infections of various kinds (COVID-19, Lyme, Herpes Zoster, etc.)
- Nerve cell degeneration
- Some types of drugs
- Insufficient blood supply
- Anomalies of blood vessels
Depending on the damaged nerve, the symptoms of the affected person vary; in the case of eyesight, for example, several situations can occur:
- If the optic nerve is damaged, the affected eye may partially or completely lose sight
- If any of the 3rd, 4th, or 6th cranial nerves are damaged, the person is no longer able to move their eyes.
- In the event of damage to the 3rd cranial nerve (oculomotor), the subject is no longer able to lift the eyelid
A medical evaluation, tests of cranial nerve function, and usually magnetic resonance imaging are required to make a diagnosis.
To be able to intervene in the problem, it is necessary to identify and treat the cause.