NEURITIS, a term denoting inflammation of nerve fibres. Two varieties are known, the localized and the multiple. The localized form frequently follows exposure to cold and may attack a single nerve. Facial paralysis (Bell's palsy) is commonly seen following a neuritis of the facial nerve. Neuritis may follow blows and wounds, stretching or long-continued pressure, as in a disloca tion of the elbow joint, or the nerve may be involved in a neigh bouring inflammation. The first symptom of a localized neuritis is boring pain along the course of a nerve and its distribution, the part being sensitive to pressure.
Multiple neuritis or polyneuritis may affect many of the periph eral nerves symmetrically and at the same time. For the patho logical changes see NEUROPATHOLOGY. The causes may be divided as follows : The toxins of acute infective diseases, such as diphtheria, influenza, typhoid fever, malaria, scarlet fever and septicaemia. (2) Acute or chronic poisoning by lead, arsenic, mercury, copper and phosphorus. (3) General disorders: gout, rheumatism, tubercle, carcinoma. (4) The local action of leprosy and syphilis. (5) Endemic disease: beri-beri (q.v.). (6) Alcohol, the most common. Alcoholic neuritis is a result of constant steady drinking, particularly of beer. It begins with numbness of the feet and later of the hands, then painful cramps in the legs appear and there is pain on moving the limbs, and superficial tenderness is occasionally present. In other cases the earliest symptoms are weakness of the legs and extreme fatigue, leading to a character istic "steppage gait," or marked incoordination of movement may occur and the gait become ataxic. Trophic changes soon appear, early and rapid muscular wasting occurs, the skin becomes dry and glossy, the nails brittle and the hair thin. In time contractures take place, the hip and knee-joints become flexed and the foot dropped at the ankle. Should the case progress the patient may become bedridden and powerless, and degenerative mental changes may take place, loss of memory, irritability of temper and emo tional instability. Early cases may recover completely under treat
ment. The galvanic and faradaic currents combined with massage are useful in helping to restore the wasted muscles, and hot-air baths and warm applications are appreciated.
Arsenical neuritis mostly affects the lower extremities, as con trasted with lead, which mainly paralyses the fingers and wrists; recovery is even slower than in alcoholic neuritis, the treatment being on the same lines, with the removal of the cause of the dis ease. In the neuritis of chronic lead poisoning a fine tremor of the hands is an early symptom and sensory symptoms are usually absent; the muscles affected are the extensors of the wrists, thumb and fingers (see LEAD POISONING). The course of the disease is long, and an attempt should be made to eliminate the lead from the system by purgatives and the administration of potassium iodide.
In diabetic neuritis paraesthesia is slight, and the legs are chiefly affected ; weakness and ataxia may be present. Trophic sores on the feet are of frequent occurrence in this variety. The treatment is that of the disease.
Post-diphtheric neuritis occurs in about 1o% of all cases of diphtheria. Paralysis of the soft palate is the earliest, and may be the only, symptom. The limbs are affected much later, usually about the fifth or sixth week. Atrophy of the muscles is frequently rapid. If the respiratory muscles are unaffected the prognosis is good, but the paralysis of the limbs may last for several months. The treatment is complete rest, good food and the administration of strychnine.
Acute polyneuritis with numbness and motor weakness has been noted after influenza, together with slight muscular wasting and electrical degeneration. Later, there is loss of sensation in the peripheral portion of the limbs, and the motor weakness may affect the muscles of the trunk and face. Such cases tend towards complete recovery.