RESULTS OF RETROGRADE URETHROGRAPHY IN CATS WITH IDIOPATHIC, NONOBSTRUCTIVE LOWER URINARY-TRACT DISEASE AND THEIR ASSOCIATION WITH PATHOGENESIS - 53 CASES (1993-1995)

Objective - To describe results of retrograde urethrography in cats wi th idiopathic, nonobstructive lower urinary tract disease (LUTD), to r eview the normal anatomy of the feline urethra, and to relate anatomy observed radiographically to the pathogenesis and diagnosis of LUTD in cats. Design - Retrospective case series and anatomic study. Animals - 53 cats with signs of nonobstructive LUTD for which an underlying ca use could not be determined. Results for these cats were compared with those for 6 healthy female cats undergoing urethrocystoscopy for anot her study and 6 male cats without a history of LUTD undergoing necrops y examination. Procedure - Medical records, results of positive-contra st retrograde urethrography (cats with idiopathic, nonobstructive LUTD ) and urethrocystoscopy (healthy female cats), and necropsy findings ( healthy male cats) were reviewed. Results - Abnormalities were not det ected during urethrocystoscopy, dissection, or urethrography. Previous ly, the urethra in male cats has been described simply as a long tube that tapers caudally, and the only structures consistently differentia ted by radiography have been pelvic and penile parts. In this study, t he seminal colliculus, isthmus of the urethra, preprostatic part of th e urethra, and urethral crest were consistently observed in male cats in addition to pelvic and penile parts. The urethral crest also was ob served in the comparatively simple female urethra. Clinical Implicatio ns - During retrograde urethrography in cats, prior distention of the bladder with positive-contrast medium may obscure radiographic signs a ssociated with normal anatomic structures. Knowledge of urethral anato my and radiographic signs associated with idiopathic, nonobstructive L UTD in cats should improve understanding of the pathogenesis and diagn osis of this disease.