Neuritis is a complex process involving inflammation of the nerves, resulting in irritation that interferes with normal nerve function and the areas served. Specifically, it affects the peripheral nerves (those outside the brain, spinal cord, or central nervous system), blocking sensory and motor functions, with pronounced symptoms.
Patients with acute brachial plexus neuritis are often misdiagnosed as having cervical radiculopathy. Acute brachial plexus neuritis is an uncommon disorder characterized by severe shoulder and upper arm pain followed by marked upper arm weakness. The temporal profile of pain preceding weakness is important in establishing a prompt diagnosis and differentiating acute brachial plexus neuritis from cervical radiculopathy.
The cause of optic neuritis is unknown. Sudden inflammation of the optic nerve (the nerve connecting the eye and the brain) leads to swelling and destruction of its outer shell, called the myelin sheath. The inflammation may occasionally be the result of a viral infection, or it may be caused by autoimmune diseases such as multiple sclerosis. Risk factors are related to the possible causes.
The main symptoms of neuritis are a tingling and burning sensation, and stabbing pains in the affected nerves. In severe cases, there may be numbness, loss of sensation, and paralysis of the nearby muscles. Thus temporary paralysis, of the face muscles may result from changes in the facial nerve on the affected side. During the acute stage of this condition, the patient may not be able to close his eyes due to a loss of normal tune and strength of the muscles on the affected side of the face.
Optic neuritis is suspected in patients with characteristic pain and vision loss. Neuroimaging, preferably with gadolinium-enhanced MRI, may show an enlarged, enhancing, optic nerve. MRI may also help diagnose multiple sclerosis. Fluid attenuating inversion recovery (FLAIR) MRI sequences may show typical demyelinating lesions in a periventricular location if optic neuritis is related to demyelination.
Visual loss. The extent of visual loss associated with optic neuritis varies. Some people experience severe difficulty seeing, while others might not notice any changes in their vision. Vision loss, should it occur, usually develops over a day to a week and may be worsened by heat or exercise. Vision loss is usually temporary, but in some cases, it may be permanent.
Vestibular neuritis – in most cases, vestibular neuritis is a self-limiting condition that only occurs once in a person’s lifetime. However, some mild dizziness when moving the head may continue for several years following the infection. For the remaining five per cent or so of cases, the symptoms recur. The condition is then considered to be another type of balance disorder, such as Meniere’s syndrome or benign paroxysmal positional vertigo (BPPV).
Since the Optic Neuritis Treatment Trial (ONTT), doctors have discovered that treating patients with intravenous steroid medication (but not oral steroids) reduces the risk of developing MS later on. This finding is very significant since approximately 50% of those who experience an initial occurrence of optic neuritis will develop MS. While this treatment has little if any impact on vision, it is important for overall health.