Cystourethroscopy is becoming more popular for diagnosing hematuria-related disorders. Although equipment availability, the
patient's size, and the need for sedation or anesthesia can be limiting factors, lower urinary tract endoscopy allows localization
of the source of hematuria, direct visualization of lesions, the opportunity to biopsy lesions with less chance of seeding
neoplastic cells, and therapeutic options such as lithotripsy.
Endoscopy provides an excellent method of establishing one or both kidneys as the source of hematuria by enabling visualization
of blood-tinged urine flowing from the ureteral openings into the bladder (Figure 8). Rigid endoscopy allows visualization of the bladder and urethra in patients weighing > 6.6 lb (3 kg) and < 44 lb (20 kg),
including female dogs and cats and male cats that have undergone perineal urethrostomy. Flexible endoscopes allow examination
of the lower urinary tract in most dogs and cats regardless of size or sex.6,7
Figure 8. Note the blood-tinged urine emerging from the ureter opening (arrow) into the bladder as visualized on cystoscopy.
If less-invasive diagnostic tests have not revealed the source of the hematuria, abdominal exploratory surgery may be indicated.
An exploratory not only allows gross examination and biopsy of the urogenital system, the ureters can be catheterized individually
to determine whether blood is present in the urine produced by one or both kidneys.
Before performing biopsies or exploratory surgery in patients with hematuria, perform a coagulation profile to establish that
excessive bleeding is unlikely to occur. An activated clotting time could be used as a screening test, but it is not as sensitive
of an indicator of bleeding potential as are the prothrombin time, partial thromboplastin time, and platelet count included
in a standard coagulation profile.