A system of practical medicine. By American authors. Vol. 4

by Unknown

I have only seen one case where the lower end of the urethra was dilated without any recognizable cause for it. This was a single lady, thirty-five years of age, a school-teacher. She had displacement of the uterus and catarrh of the cervical canal, for which she consulted me. She had no trouble with her urinary organs. While examining the uterus I noticed that the meatus urinarius was peculiarly formed. In place of the concentric corrugations of the mucous membrane which form the closed meatus, the orifice was funnel-shaped and lay open when the labia minora were separated. About half an inch of the lower end of the urethra admitted a No. 21 (Eng.) sound. The remainder of the urethra was normal, and there were no signs of disease about the mucous membrane of the dilated portion. I could obtain no history which pointed to the origin of the trouble, and it caused no discomfort to the patient.

Dilatation of the posterior or upper third occurs in connection with other pathological conditions, such as prolapsus of the bladder and urethra. On this account we will defer what is to be said on this subject until we come to dislocations of the urethra.

Dilatation of the middle third of the urethra is more common than that of any other portion of the canal. In this form the anterior wall of the urethra maintains its normal position, but the central position, being distended, settles down, so that in time the urethra, in place of being a straight or slightly curved canal, becomes triangular, the upper wall being the base, and the central portion of the wall (that is, midway between the neck of the bladder and the meatus) the apex. A sac or cavity is thus formed in the central portion of the urethra.

In the earlier stages of this affection the urethra in front and behind the pouch is really or apparently contracted; but as the disease progresses the upper part of the canal and the neck of the bladder become dislocated downward, and finally the upper portion of the urethra becomes also dilated to some extent.

There is in this as in the other forms of urethral dilatation frequent urination, usually more marked, but, unlike the others, there is difficulty in passing water. This frequency of urinating, and the straining efforts necessary to do so, affect the bladder, producing irritation, and in time hypertrophy of its walls. Cystitis also follows in the order of morbid developments; but whether that comes from the frequent and difficult urination, or from extension of the inflammation from the urethra to the bladder, is a question.

ETIOLOGY.—The hyperæmia of the urethra which occurs in pregnancy, and which tends to produce over-distension of the veins, favors dilatation of the whole urethra. There is an apparent increase of tissue in the walls of the urethra during utero-gestation, and the dilatability of the canal is often increased also. Now, this condition of the parts disappears during the involution which takes place after delivery; but when from any cause the process of involution is interrupted, the enlarged vessels and relaxed condition of the urethral walls remain and sometimes increase. When to this state of the parts a catarrh of the mucous membrane is added, the enlargement of the membrane by swelling still further increases the calibre of the canal.

The dilatation caused by the passage of calculi may remain permanently, and the same may be said of the use of large sounds. Neoplasms obstructing the meatus or stricture at that point may so obstruct the escape of the urine as to cause dilatation at all points above. This is no doubt one of the most important and frequent causes of dilatation.

I have already stated that dilatation of the lower third of the urethra is rare, and is usually due to inflammation of the mucous membrane at that point or to abnormal growths, the distension remaining after the causes that produced it have been removed. This and mechanical dilatation from any cause cover the etiology of this form of the trouble. Baker-Brown says that the meatus is always dilated when there is stone in the bladder.

Regarding dilatation of the upper third of the urethra, I am inclined to believe that it occurs in consequence of a partial prolapsus of the bladder and the upper end of the urethra. The displacement of these parts implies a relaxation of the tissues, caused originally, it may be, by injuries during confinement, and the prolapsus permits an unusual pressure of the urine upon the upper end of the urethra, and dilatation is the result. On the other hand, the prolapsus and accompanying relaxation of the urethral walls may be sufficient to cause the dilatation. In all the cases that I have critically examined there has been displacement as well as dilatation, and the whole trouble could invariably be traced to childbearing or anteversion of the uterus.

One cause of dilatation of the middle third of the urethra (urethrocele) has been sufficiently dwelt upon in Bozeman's description of the pathology of that affection—that is, narrowing of the lower end of the urethra. This does not explain the etiology of all cases, however, for I have seen this form of dilatation where there was no stricture or hypertrophy of the lower end of the urethra. In such cases I have traced the cause to childbirth, during which the posterior wall of the urethra had been pushed downward and contused, while the upper remained in its normal position. The relaxation caused by this over-stretching of the urethral wall formed a small pocket in the central portion, which gradually dilated more and more by the pressure of the urine until the urethrocele was fully developed. This explanation of the cause may be rather hypothetical, but, so far as my observations go, it agrees with the facts found in those cases which cannot be accounted for by Bozeman's views on the pathology of this affection.