The electrical reactions in simple neu ritis vary with the intensity of the dis ease, being in the milder cases nearly. or quite normal, but showing in all of the severe forins a partial or complete reaction of degeneration.
The duration of a simple neuritis de pends chiefly upon the severity or cura bility of the initial lesion. The symp toms may pass off in a few days, or may persist for months. Becovery is the rule, and is always obtained, provided the cause is one which can be removed. In very unfavorable cases some permanent contracture or paralysis inay result.
Pathology. — In simple neuritis the chang,es are chiefly localized in a limited portion of the nerve-trunk, only the degenerative changes in nerve-fibres, • ere Nrenellymatous lesion is I rt. t te ilding along the entire distal ii of the nerve. At the point of the nen e-trunk is red. swelled, I with lymphoid elements, I may be surrounded by a gelatinous iniate. The changes involve especially t. e p-rineural and interstitial connec t. \ e-tissue frame-work. In mild cases e nerve-fibrils themselves are slightly, if at all, involved; in severer cases, or where the fibrils have undergone com pression from swelling of connective tissue structures, the nerve-fibrils show the alterations of parenchymatous neu ritis; their mvelinic sheaths are frag mented, the nuclei of the sheath of Schwalm and of the internodal cells are increased in number, or may seem swelled: in still more severe eases the axis-el-Enders show marked degenerative alterations, become varicos.e, swell, disin tegrate, and even entirely disappear, the appearances being then nearly identical with those of a true Wallerian degenera tion. These changes in the axis-cylin ders necessarily involve all of the nerve fibre lying below the seat of injury, but .nre usually arrested at the first node of Ranvier above, although in some cases -they may extend upward, even quite to the cord. The blood-vessels at the seat of an injury are often distended, and minute hmmorrhages into the nerve are of not infrequent occurrence. The dis ease may go on to complete destruction of the nerve-elements, the degenerated fibres being replaced by connective tis sue and by fat-cells: a condition, when the fat-deposits are abnndant, called by. Leyden "lipomatous neuritis." Regener ation begins after a short time, and, if the original nerve-injury be removed, the nerve may, even in very severe cases, ulti mately regain its former healthy state.
Many cases of mild neuritis pass un recognized, being looked upon as rheu matism.
Peripheral neuritis may be isolated, confined to one or a few nerves; it may be mnItiple, symmetrical in its distri butions, affecting the nerves of all the extremities. In isolated neuritis the dis
ease begins in the nerve-sheath, consti tuting a "perincnritis," the inflammation extending to the nerve-fibres afterward. In the multiple forms the nerve-fibres themselves are the seat of the primary change, the sheath becoming affected later. These forms of multiple "paren chymatous" neuritis are always due to some virus in the blood, an organic or in organic chemical compound usually. Iso lated neuritis is due to some cause act ing locally, and if several nerves are af fected their distribution is irregular, not symmetrical. In these eases there is al ays a constitutional cause at IA ark as well, predisposing to the disease.
Alcoholic peripheral neuritis is the form most often met with.
The recurrence of neuritis as the re sult of medicinal use of arsenic is not very rare. Of predisposing causes in isolated peripheral neuritis, gouty and rheumatic conditions are among the most frequent. Litlimmia should be added to these. Lithmmia is probably the most frequent predisposing condition leading to the development of inflamma tion of the nerves after injury to them. Alexander 111ePhedran (Med. .News, Oct. 31, '96).
Treatment.—As a necessary prelimi nary to any treatment, the cause of the disease must be removed. After this, rest of the affected part, absolute and continued for several days, should be in sisted upon. The use of splints to limbs is sometimes advisable. Heat, especially moist heat,—as from steam. poultices, or fomentations,—gives great relief from the pain. Counter-irritation by mustard plasters or other means is sometimes equally efficacious. In many instances the galvanic current used in strength sufficient to redden the skin gives im mediate and wonderful relief. Occa sionally in early stages ice locally ap plied will give more relief than anything else. Of internal remedies, salol, the salicylates, and the whole series of coal tar derivates—in particular, antipyrine, phenacetin, and acetanilid—may be used in the confident expectation of obtaining measurable relief from the pain. When other remedies fail the local hypodermic use of morphine is, where pain is very intense, justifiable. The early use of mercurials—calomel or blue mass—is often attended by good results. In any case the bowels should be kept open by salines or a simple purgative pill. Attention should be paid to the general health. In most instances tonics and alteratives will be found beneficial.