Myelin sheath is a layer white fatty material around your nerves that facilitates rapid and efficient transmission of impulses. It’s the myelin that gives the whitish appearance of your brain’s nerve fibers.
Myelin is primarily composed of lipids and lipoproteins and its sheath surrounds many of your nerves in your brain, spinal cord and periphery. The cells that form your myelin sheath are Schwann cells in the peripheral nervous system and oligodendrocytes form the myelin in the central nervous system.
When your myelin is affected in any way, your nerve impulses will slow down. Demyelination means myelin is lost, which can lead to patches of nerve scarring, aka sclerosis. Dysmyelination means myelin is defective in its structure and function, for which lesions are not usually a health issue.
Under healthy conditions, your myelin can regenerate fairly quickly after being damaged. And when peripheral nervous tissue is damage, growth and repair is possible along the myelin sheath. However, unmyelinated fibers and myelinated axons of the central nervous system do not regenerate.
When myelin sheath is being impacted by some health condition, you’ll likely experience neurological symptoms like:
Some of the health conditions that can cause some sort of myelin issue or demyelination involve:
- neuritis ~ inflammation causes myelin injury
- peripheral neuropathy ~ myelin degeneration
- transverse myelitis ~ inflammation can cause myelin damage
- multiple sclerosis ~ inflammatory disease causing demyelination
- infantile Refsum disease ~ white matter abnormalities of brain myelin
- pernicious anemia, vitamin B12 deficiency ~ impairs myelin formation
- Bell’s palsy ~ virus infection causes facial nerve inflammation, damaging myelin
- femoral nerve dysfunction, carpal tunnel, sciatica ~ nerve entrapment destroys myelin
- neurofibroma ~ tumor of peripheral nerves due to abnormal proliferation of Schwann cells
- trigeminal neuralgia ~ blood vessel pressing on the trigeminal nerve, wearing away myelin sheath
- Guillain-Barré syndrome ~ autoimmune disease wherein immune system antibodies destroys myelin sheath
- Charcot-Marie-Tooth disease ~ gene mutation causes proteins production problems involving myelin sheath
- leukodystrophy ~ progressive degeneration of brain’s white matter due to imperfect growth, development of the myelin sheath
With many of these health conditions, the myelin sheath is not the only part of your body disturbed.