MORBID ANATOMY - URETHRITIS Inasmuch as the anatomical features of specific and simple urethri tis differ in degree only, the morbid anatomy of the disease in general may be properly taken up at this point. The infection of urethritis is generally supposed to begin at the meatus. Milton has remarked the apparent contradiction of urethral chancre and chancroid as • regards the site of inoculation. He believes that in such cases the virus is deposited at the lips of the meatus and subsequently diffuses itself until it meets with a susceptible portion of mucous membrane. It is a question whether morbid secretions may not be drawn into the urethra during coition. The author firmly believes that they may he. It would seem that a certain amount of aspiration is produced in the urethra during the venereal orgasm, sufficient at least to draw secretions from the vagina into the urethra. The alternate contrac tion and relaxation of the deep perineal muscles incidental to the efforts of the urethra to clear itself of semen during the venereal act must necessarily produce a more or less marked suction at the meatus. It is the author's impression that the inflammation really begins in the fossa navicularis rather than at the meatus proper.
The extent to which the urethra is involved is variable. The inflammation is generally most marked in the anterior portion of the canal, but in the severe types almost always involves the entire canal down to the bulbo-membranous junction and in many cases extends to the posterior urethra. The entire mucous membrane of the urethra from the meatus to the bladder may be infected. In the milder forms of urethritis the pathological changes consist in a few instances of slight hyperemia with attendant reddening and hypersecretion. In by far the majority of cases, however, there will be found chronic changes in the canal produced by a previous attack of virulent ure thritis. The pathological anatomy of simple acute urethritis and that of chronic urethritis are therefore usually identical and should be described simultaneously. In simple urethritis with a chronic inflammatory foundation, the localization of the chronic inflamma tion, with perhaps the formation of stricture or abraded granular and congested patches, is due to several causes : (1) The most impor tant is the relative inelasticity of the portion of the urethra in volved. This produces friction during micturition with consequent localization of the inflammation at the particular point affected.
(2) Dilatation and severe inflammation of mucous follicles at one or more points in the canal. (3) Injury of the canal at different points clue to the introduction of instruments, the long-nozzled the most frequent cause. (4) The spontaneous or traumatic yielding of the corpus spongiosum in the course of a chordee. (5) Slight thickening of the urethra due to previous traumatism. In cases in which posterior urethral infection—prostatitis—has occurred in the course of acute gonorrhoea, more or less enlargement of the organ is found, together with a varying degree of interstitial thickening and chronic inflammation in the prostatic ducts and follicles.
In the severe forms of urethritis the principal change consists in intense hypercemia with swelling of the mucous membrane. This is attended by a diminution in the calibre of the canal which may re sult in complete retention of urine. When the inflammation is at its height, there exists an infiltration of the corpus spongiosum resulting in thickening and inelasticity of that structure. Late in the history of the case this plastic infiltration either disappears entirely or, as is very frequent, localizes itself at certain points. These points are usually the posterior portion of the fossa navicularis, the lacuna magna, and the bulbo-membranous junction. • Other points in the pendulous urethra are frequently involved. It is in these situations that we are most likely to find stricture. The follicles of the urethra are found to be dilated and filled with purulent or muco-purulent secretion. Herpetic excoriations are occasionally seen. In view of the severity of the inflammation in some cases, it is singular that true ulceration does not more often occur. It is, however, very rare. The epithe lium lining the urethra will be found abraded here and there in all cases in which the inflammation is of a high grade. In some in stances it is almost entirely removed throughout the extent of the canal. Superficial erosions of the mucous membrane result from abrasion of the epithelium. In chronic cases the pathological factors which are most important as explaining the persistency of the dis ease are stricture, congested and granular patches, enlargement of the lacuna magna, dilatation and inflammation of the glands of Littre and sinuses of Morgagni, and follicular prostatitis—i.e., so-called posterior urethritis.