The local causes are numerous. Pelvic inflammations, as cellulitis or pelvic peritonitis, give rise to the disease. Affections of the uterus are frequent causes; displacements, as retroversion or prolapsus; and inflammation, either parenchymatous or of the endometrium. Quite a moderate grade of inflammation, as found during the interval, may, under the increased congestion of menstruation, become extreme. Many cases doubtless depend upon an ovarian influence even when no affection of these organs can be made out. Scanzoni hazards the theory that the maturation of Graäfian vesicles lying deeper than usual in the stroma of the ovary is one cause of this form of dysmenorrhoea.

In neuralgic dysmenorrhoea the neurotic element preponderates. The nerves play a part corresponding to that of the vessels in the congestive form. In some cases of this class no organic lesions can be discovered, and they are then termed idiopathic.

This form of dysmenorrhoea depends upon either a peculiar condition of the general nervous system or upon hyperæsthesia of the sexual system, or both combined. Either or both may have been inherited or acquired. It is frequent in subjects of the hysterical temperament, and in those presenting that preponderance of the nervous system so often seen as the result of over-refinement, luxury, habits of idleness, and other violations of hygienic law. Those subject to it often suffer from severe headaches, neuralgia, and other nervous affections. It is often caused by anæmia or chlorosis. Sexual influences, psychical or physical, and especially those that excite without satisfying, are sometimes efficient causes. Ovarian influence is often an important factor; some authorities designate all those cases in which no anatomical change can be found, ovarian. The prodromata of this form are very apt to be some of those nervous attacks to which such patients are liable, as headache or neuralgia, and they may be psychical, as aberration of temper, undue irritability, or tendency to melancholy. In character the pain is generally stated to be more acute than in the other forms. It is subject to great and sudden alternations. In acuteness and irregularity it often justifies the term spasmodic. From these characters and from the absence of anatomical change a differential diagnosis may be made. As in this form the most marked nervous symptoms are witnessed, so are also the most pronounced complications on the part of the general nervous system. They are often hysterical in character, but may be of every kind and degree, even to general convulsions, and mental aberration is sometimes a complication or result.

Membranous dysmenorrhoea is characterized by the expulsion at the menstrual periods of organized membrane, either as a whole or in pieces. In the former case it is like a cast of the interior surface of the uterus. The expulsion of this membrane is accompanied by pain, often of the most severe character. The pain presents well-marked features; it is markedly expulsive, identical with that of the obstructive form, closely resembling an abortion, to which the membrane adds an additional element of similarity. This pain and these expulsive efforts may continue twelve, eighteen, or twenty-four hours, and then cease, to be renewed only at the next period.

This form of disease is rare—so rare that observers having a large field of observation may never meet with over half a dozen cases. In regard to many points very diverse views are held, and the limits of a practical work do not permit even a statement of all of them. The nature of the membrane is one of these points too important to pass over. When thrown off entire, its internal surface is smooth and marked by the openings of the utricular glands; its external or uterine face is rough and villous. It presents the exact shape of the interior of the uterus, with openings corresponding to the Fallopian tubes and the os. It is impossible to escape the conviction that this membrane is the lining membrane of the uterus, thrown off as a whole, instead of by gradual melting down of its superficial layers, as in normal menstruation. The microscope sustains this view, and this is the generally received opinion; yet that the membrane is not always such is testified by competent observers from observations with the same instrument. It seems probable that this disputed point will be settled, as have been so many others in medicine, in favor of both parties. Siredey suggests the possibility of different kinds of membrane in these cases, while Barnes boldly states this as a fact.

Various theories have been advanced to account for the formation of the membrane. An abnormal course of conception, a changed ovarian influence, a peculiar endometritis, have been from time to time favorite terms in which to express our ignorance. Only in regard to the first has unanimity been obtained. That the membrane is always a product of conception is not now maintained by any respectable authority. It is a well-established fact of the utmost importance that such membranes may be expelled when there has never been sexual intercourse.

The membrane of dysmenorrhoea is to be distinguished from fibrinous masses, the remains of blood-clots from which the corpuscles have been squeezed; from mucus coagulated into shreds by astringent injections; and from the products of membranous vaginitis. Neither of these will present much difficulty with the aid of the microscope. The case is very different, however, when the membrane is to be distinguished from the decidua of an early pregnancy. From a single specimen or a single attack a diagnosis cannot be made. Thomas gives an instance of disagreement as to the nature of the same membrane by two of the highest microscopical authorities. The recurrence of the attacks at the regular menstrual periods will establish the diagnosis.

The prognosis of dysmenorrhoea varies in the different classes. In the obstructive form it will depend upon the curability of the lesion upon which it depends, and the same may be said of the congestive. The neuralgic cases do not yield readily to treatment, especially when dependent upon a peculiar and perhaps inherited nervous constitution. Caution should be exercised, however, in expressing an unfavorable prognosis. Like all nervous diseases in the female, it is subject to great mutations without apparent adequate cause, and will sometimes suddenly disappear in an inexplicable manner.

The membranous form affords still less promise of cure: the unsatisfactory results of treatment are generally acknowledged.

During an attack of dysmenorrhoea the patient should remain in bed for the benefit of rest and warmth. In those cases where the flow is not too free, and especially when relief follows its appearance, active measures to promote this end may be instituted by hot drinks and hot fomentations. In married patients a hot sitz-bath, during which the vaginal syringe is used to douche the uterus, is an efficient measure. Pain being the prominent symptom, and remedies for its relief being at hand and reliable, the indication is clear and the treatment can be briefly stated. In execution, however, it is not a simple problem: immediate relief is not alone to be considered. If opiates be resorted to for frequently-recurring pain, a habit will soon be formed that is no less a calamity than the disease itself. While, therefore, opium and its preparations are reliable remedies, and in many cases indispensable, they should be administered as seldom and as sparingly as possible, and always with an appreciation of possible injurious consequences. Many cases can be successfully managed with chloral hydrate, or belladonna, or Indian hemp. When opiates are resorted to, they should be combined as much as possible with other medicines by which their effects are modified, and relief afforded with the smallest possible dose. Thus in cases attended with vascular excitement these ends may be attained by the union of opium with tartar emetic or aconite; when there is marked disturbance of the nervous system, it may be combined with an antispasmodic, as the compound spirit of ether. Administration by the rectum will produce a local as well as a general effect, and injections of starch and laudanum or suppositories of opium and belladonna may be administered. The speediest and most certain relief is afforded by the hypodermic syringe. Resort to it should, however, be rigidly controlled; it should be used as a miser uses his gold, and it need scarcely be added that only very exceptional, if any, circumstances will ever justify placing the syringe in the hands of friends or attendants, no matter with what restrictions. Unfortunately, this is sometimes done, but very rarely without great injury resulting.