MORBID ANATOMY - STRICTURE.
As might be inferred from its origin, the characteristic changes at the site of a stricture are essentially those of chronic inflammation. Urethritis having become localized at some point or points in the canal, the inflammation extends to the submucous tissue, or if peri urethral thickening already exists, it 'is increased; the process con sisting of a submucous infiltration of embryonal cells, which even tually form a zone of peri-urethral sclerosis of variable density. There may or may not be a variable degree of infiltration and thickening of the corpus spongiosum. The result of the adventitious deposit is an encroachment upon the lumen of the canal and a loss of elasticity commensurate with the degree of the pathological pro cess. In some instances there is a slight thickening 4 the mucous membrane with little or no submucous infiltration, the mucous epithe lium being lost to a greater or less extent, and the part covered with muco-purulent secretion. The follicles of the urethra at this point are dilated and thickened and show evidences of hypersecretion. At a more advanced stage the mucous membrane becomes extremely thickened, congested, and perhaps covered with fungoid granulations. In old and pronounced cases the corpus spongiosum is extensively infiltrated and of a semi-cartilaginous consistency. The condition, in brief, is one of chronic interstitial inflammation. Bridles, bands, or flaps of thickened mucous membrane may be present. The degree of occlusion of the canal is variable. In some cases the process is localized, perhaps only partially involving the circumference of the canal, its lumen being very slightly contracted. In the more marked forms the occlusion may be almost complete.
The secondary results of stricture are due to three conditions : 1. Mechanical obstruction to the outflow of urine; 2. Germ infec tion; 3. Extension of chronic inflammation. The urethra anterior to the stricture may be somewhat contracted, this being due to its partial loss of function. Posterior to the stricture the urethra is more or less dilated and contains a greater or less quantity of residual urine in combination with the products of infections inflammation and decomposition. This secretion alone or combined with epithelium rolled up by the outflowing urine appears at the meatus in the form of a characteristic gleety discharge or as the so-called Tripperfaclen i.e., shreay filaments which float about in the urine. The secretion
may be mixed with more or less blood if the mucous membrane be extremely congested. Crystallization of urinary salts with resulting urethral calculus may occur behind the stricture. As the case ad vances, the mucous membrane behind the obstruction becomes thinned and perhaps ulcerated. It may give way during a straining effort at micturition. The infectious urine under such circumstances escapes into the pen-urethral cellular tissue and produces abscess with re sulting fistula, or possibly infiltration of urine with acute septic cellulitis and death. All of the glandular tissues tributary to the urethra are involved in the chronic inflammation. The urethral follicles, prostate glands, Cowper's ducts, and the ejaculatory ducts become dilated and thickened. The bladder is always involved to a greater or less degree. It is mechanically disturbed as a result of the backward prepsure of the urine during micturition. It is also likely to become affected by chronic inflammation either by exten sion or by the upward migration of germs. The bladder may be come sacculated, undergoing precisely the same changes as in long standing cases of prostatic hypertrophy. Thickening of the bladder walls, severe chronic cystitis, vesical calculus, and involvement of the ureters and pelvis of the kidney are possible results. Pyelitis with or without the formation of renal calculi will be found to exist in cer tain extreme cases. Pyonephrotic or perinephritic abscesses may occur. In a general way the secreting structure of the kidney may be said to undergo those changes which are described under the om nibus term "surgical kidney," involving chiefly an interstitial prolif eration of connective tissue and a deficiency of the elements of the normal stroma. The kidney is always more or less hyperaemic. Its cortical structure may be dilated and thinned. The condition of the kidney is such that a complete inhibition of its function may follow a slight increase of hyperaemia. Reflex shock upon such a damaged kidney incidental to operations upon the genito-urinary tract, or direct irritation from anaesthetics, and particularly ether, are liable to precipitate uroemic coma or convulsions and death.
The density of the stricture varies with its origin, duration, and the amount of irritation present. Traumatic and chemical strictures are typically cicatricial.