Tic-doulourenx in the form of severe neuralgia which is by far the most commonly met with; the reason probably being that the trifacial nerve lying superficially, and being distributed over a part of the surface which is usually nnprotected by any arti ficial covering, is very liable, for that reason, to be affected by exposure to atmospheric influences, which are undoubtedly to be included among the exciting causes of this disease. Amongst other seats of neuralgia may be mentioned the arm, especially the fore-arm, the spaces between the ribs, especially between the sixth and ninth, and the lower extremity, where it most frequently affects the sciatic nerve, giving rise to the affection known as SCIATICA, which, however, not always being pure neuralgia, will be noticed in a separate article.
The causes of neuralgia are various. Excluding inflammation of the nervous trunk or neuritis, the pain may be excited by a tumor pressing on the nerve, or originating in its substance; or by roughness of a bony surface with which the nerve may be in contact, as when it passes through a foramen: or it may be due to tumors within the cranium., or a morbid state of the spinal cord. Sometimes, again, irritation applied to one branch of a nerve will give rise to pain at the extremity of another branch of the same nerve, the sensation being reflected, along the braneb.whieltis not directly exposed to the irrita tion. In this way we may explain the pain- in the shoulder which ofte'n accompanies disease of the liver; the pain in the thigh which is often associated with irritation of the kidney:11ue pain in the left arm which is often coincident with disease of the beast, etc. Persons suffering from debility, anaemia, and a gouty or rheumatic constitution, are so especially liable to neuralgia that these conditions—as also exposure to malarious influences—must be placed among the the predisposing causes. Amongst the exciting causes, exposure to cold and wet, or to a cold dry east wind, is the most frequent ; but fatigue, strong mental emotions, the abuse of tea, coffee, tobacco, and alcholic drinks, a wound or bruise, the retrocession of gout, rheumatism, or cutaneous eruptions, etc.. occasionally suffice to excite the disease.
The resources of the materia medica have been exhausted in searching for remedies for this cruel disease. Dr. Elliotson believes that " in all eases of neuralgia, whether exquisite or not, unaccompanied by inflammation, or evident existing cause, iron is the best remedy;" and there can be no doubt that, when the disease is accompanied with debility and paleness, no remedy is likely to be so serviceable. If the digestive organs are out of order, the neuralgia may not unfrequently be removed or alleviated by cor recting their unhealthy state. " Dr. Rigby tells us that having suffered in his own per son an intense attack of tie-douloureux, which opium did not assuage, he swallowed some carbonate of soda dissolved in water. The effect was almost immediate; carbonic acid was eructed, and the pain quickly abated. In this case, the pain depended upon i the mere presence of acid in the stomach. More often the cause of offense appears to
lie in some part of the intestines; and purgatives do good. Sir Charles Bell achieved the cure of a patient upon whom much previous treatment had been expended in vtun, by some pills composed of cathartic extract, croton oil, and galbanum. He mixed one or two drops of the croton oil with a dram of the compound extract of colocynth; and gave live grains of this mass, with 10 grains of the compound galbanum pill, at bedtime. Other cases have been since reported, both by sir Charles and by others, in which the same pre scription was followed by the same success."—Watson, op. cit. p. 727.
When the disease occurs in a rheumatic person, iodide of potassium (from three to five grains taken in solution three times a day before meals) sometimes gives great relief. When the paroxysms occur periodically—as. for example, with an interval of 24 or 48 hours—sulphate of quinine in doses of from 10 to 20 grains between the paroxysms, will usually effect a cure; and if the disease resist comparatively small doses, the quan tity may be increased to half it dram, or a dram if necessary. Arsenic acts in the same manner as quinine in these cases, hut usually less effectually.
The inhalation of chloroform will sometimes give permanent relief, and always gives temporary ease, and shortens the period of suffering.
The injection of a certain quantity of a solution of muriate of morphia, by means of a sharp-pointed syringe, into the cellular tissue beneath the skin over the painful spot, very often gives immediate relief. For the discovery of this mode of treating neuralgia, we are indebted to Dr. Alexander Wood of Edinburgh. At one lime—about half a tury ago—it was a common practice to divide the trunk of the painful nerve, with the object- of cutting off the communication between the painful spot and the brain; but in i many instances the operation signally failed, and it is now never, resorted to. A much simpler operation, namely, the extraction of a canine tooth, has often been found to give permanent relief in cases of facial neuralgia, and in such case a careful examination of the teeth should usually be made.
Local applications can be of no permanent service in cases where the pain results from organic chenee. or from general constitutional causes; they will, however, often give considerahie temporary relief. Amongst the most important local applications may be mentioned laudanum, tincture of aconite (or aconitina ointment, in the proportion of one or two grains to a dram of simple ointment or cerate), belladonna plaster, and chloroform (‘'‘;hich should he applied upon a piece of linen saturated with it, and cov ered with oiled silk, to prevent evaporation).
Lastly, neuralgia being a purely nervous affection, is often influenced by means cal culated to make a strong impresSion on the mind of the patient ; and hence it is that gal vanic rings, electric ebains,mesmeric passes, homeopathic globules. and other applications. which, like these, act more upon the mind than upon the body of the patient, occasionally effect a cure.