How to do Urinary Tract Endoscopy

Endoscopy of the urinary tract is a useful diagnostic aid in patients presenting with abnormal urination or hemospermia which is not associated with lesions of the prepuce or distal penis. In addition, it may be a useful way to ensure a patient has two functional kidneys present when one kidney cannot be imaged during ultrasonographic examination. Endoscopic examination of the urinary tract is performed on standing, sedated horses re- strained in a set of stocks. A 100 cm long flexible endoscope with an outside diameter of 12 mm or less and a minimum length of 1 meter is adequate for visualization of the urethra and bladder of an adult horse of either sex. In foals, a smaller diameter endoscope is required. The endoscope should be sterilized prior to examination. Rectal palpation should be performed initially to empty the rectum of feces (so feces do not compress an air-filled bladder) as well as to palpate the bladder for pathology and to determine if a catheter needs to be passed to empty the bladder prior to examination. After cleaning the distal penis or vulva, sterile lubricant is applied to the endoscope and it is passed into the urethra in a manner identical to a urinary catheter. Once in position the endoscope is held in place with a hand around the penis in male horses. Holding the endoscope within the penis forms a seal which allows distension of the urethra by intermittent use of the air control. Normal urethral mucosa in male horses is pale pink with longitudinal folds. When the urethra is dilated with air, the mucosal folds will flatten and progressive distension allows the submucosal vasculature to be seen. The submucosal vasculature becomes more prominent as the endoscope is advanced to the bladder. Further, passage of a catheter prior to endoscopy (for sample collection and to empty the bladder) can result in a mild linear erythema of the urethral mucosa. A slightly more pale linear area of the urethra can be visualized along the caudoventral aspect of the urethra. In mares the urethra is too short to allow endoscopic examination. […]