This disease may be confined to a single nerve, or it may involve a large number of nerves. When many nerves are involved it is known as multiple neuritis.

Etiology

Local neuritis may be caused by what is called a cold--whatever that means. A cold is something that everybody knows all about and no one knows anything about. It is a blanket term that covers a great deal of ignorance. Those who are decidedly toxin-poisoned, and those who are inebriates, morphine fiends, or given to the excessive use of food and stimulants, will be subject to this disease. When the nervous system is made sensitive, as it is in all chronic poisoning, as above hinted, a bruise, an injury, or an exposure to cold when lying heavily on one cheek, with the crease of the bed-clothes pressing against the side of the face, or any unusual pressure, will start up an aching or an inflammation. This is what is called localized neuritis; it is sometimes called rheumatic neuritis, and it is also called neuralgia.

Neuralgia or inflammation of the sciatic nerve may be brought on by the constant pressure of sitting in an uncomfortable chair. There is no difference between localized neuritis and multiple neuritis, except in degree, and the fact that in multiple neuritis a greater portion of the nervous system is involved.

Symptoms

Local neuritis is usually confined to the one nerve, and, as a rule, the constitution is not so broken down as in the other form. The most important symptom is pain. The character of the pain is on the order of pressure or bearing, sometimes stabbing; and when the pain is on, the nerve is usually sensitive to pressure along its course. Sometimes the skin is slightly reddened over the nerve; and again cases are edematous. The pain varies considerably, being sometimes intense and distressing, and at other times simply a soreness that will almost subside, and then return.

In localized affections of this character, if the nerve involved is the supraorbital and the patient is of a hysterical temperament, she may put the muscles of the eyebrow in a state of onguard and cause herself very much more suffering than she need have. Any pain protected by putting the part in a fixed position with the surrounding muscles puts everything on a strain, and in the course of a day the patient will have a great deal of suffering from the onguard state of the muscles--really more than from the pain which the fixation was assumed to relieve. In headaches of a nervous character many people build a continuous headache by knitting the brow and putting the whole front of the forehead in a corrugated, cramped position, instead of allowing the muscles to relax. It does not relieve a pain to corrugate the brow, but it intensifies it, and people who would suffer very little from headache will develop a type that will run on indefinitely, caused by cramping the brow, and otherwise developing the headache habit. Physicians must be very careful about mistaking this form of headache for neuritis or tumor of the brain.

The duration of the disease varies from a few days to weeks, but sometimes months. A slight neuritis from injury may pass off in about a day or two, while in severe cases, in unreduced location of bones, or in fracture of bones, where nerves are pressed upon, the relief will not come until the cause is discovered and removed.