Achalasia of the Ureter

The observation of 6 patients with minimal degrees of achalasia of the ureter prompted our present review of the subject. This form of megaloureter, resulting from a neurogenic dysfunction of the terminal ureter, is far less clearly recognized and understood than the comparable entities of achalasia of the esophagus, colon, and bladder, even though it is probably of more common occurrence. Radiologists in particular should be quite familiar with the disorder because of the fact that the lesions of minimal severity are often asymptomatic and are first diagnosed as incidental findings in urographic examinations. But clinicians should also be alert to its occurrence, because of the varied symptoms which may be msymptoms which may be manianifest. There is a paucity of reports in the medical literature on achalasia of the ureter per se, and much confusion with ureteral dilatation secondary to achalasia of the bladder with reflux. Many discussions of megalobladder have appeared since Swenson's proposal that this might be the result of a congenital deficiency of parasympathetic innervation with consequent failure of relaxation of the bladder sphincters. On the subject of achalasia involving only the ureter, however, we could find no articles in the radiologic literature. And nearly all authors describing ureteral achalasia refer to cases of considerable severity, with symptoms. We should like to emphasize, on the other hand, the minimal lesions, which are probably more common. Although disagreement and confusion persist in regard to the etiology and mechanism of megaloureter due to achalasia, we believe that correlation of the urologic and radiologic findings clearly establishes the syndrome to be described. Classification of Megaloureter Megaloureter, congenital megaureter, and hydroureter are all nonspecific terms used to describe dilated ureters of various etiology. In many cases the particular mechanism of the dilatation cannot be elucidated, but three broad categories are distinguishable: (a) Mechanical obstruction, due to vessels, bands, valves, membranes, and stenoses, has been described. Also to be included in this, the largest category, are obstructions distal to the ureter, namely, in the bladder and urethra, with resulting incompetence of the ureterovesical sphincter. (b) Chronic infection has been observed to cause dilatation in various parts of the urinary tract, the precise mechanism being unknown. (c) Under neurogenic dysfunction, two distinct groups can be included, namely, achalasia and its opposite, incompetence of the ureterovesical sphincter with urinary reflux. It is doubtful whether a third group, primary atony of the ureter (1) exists, although reference has been made to it (2).