Malignant urethral obstructions can cause life-threatening biochemical changes in veterinary patients. Most patients experience
significant dysuria, and a small percentage develop complete urinary tract obstruction. Urethral stenting is an effective,
minimally invasive out-patient procedure that can offer immediate relief of stranguria, as shown in the case below.
Signalment: 8-year-old castrated male beagle (48.5 lb; 22 kg)
Presenting complaint: Progressively worsening stranguria with near complete urinary obstruction
Pertinent history: Four months ago, the dog had a suspected urinary tract infection that did not improve with antibiotic therapy; results of
follow-up ultrasonography and examination of prostatic fine-needle aspirate confirmed urothelial carcinoma
Medications: Piroxicam (5 mg orally once daily), misoprostol (50 µg orally b.i.d.); owner declined chemotherapy
Physical examination findings: Quiet, alert and responsive; body condition score 5/9; multiple soft moveable subcutaneous masses; moderate bilateral hindlimb
muscle atrophy; very large caudal abdominal structure consistent with distended urinary bladder; large, firm, lobulated, irregular
prostate palpated on rectal examination; lumbar lymph nodes not palpable on rectal examination; urine dripping from prepuce
Heart rate: 140 beats/min
Complete blood count: Mild stress leukogram
Serum chemistry profile: ALT 79, AST 39, ALP 420
Abdominal radiography: Enlarged, mineralized prostate; hepatomegaly
Thoracic radiography: Unremarkable
Abdominal ultrasonography: Soft tissue mass located at urinary bladder trigone and extending into and from proximal urethra; intrapelvic urethra not
visualized; lumbar lymph nodes normal; no evidence of hydroureter or hydronephrosis; slightly enlarged hyperechoic liver;
remaining structures unremarkable
Urinalysis/urine culture: Pending
This patient was determined to have a complete or near complete urethral obstruction due to the progressive urothelial carcinoma.
Emergency department personnel inserted an 8-F urethral catheter, and 400 ml of urine with marked hematuria was removed from
the urinary bladder. The dog's rapid heart rate decreased after the bladder drainage.
Discussion with the owner included the following treatment options:
- Surgery (cystostomy tube)
- Chemotherapy (after urinary patency restored)
- Radiation therapy (palliative or full course) with periodic urinary catheterization (two or three times daily) until urethral
- Urethral stenting
Tumor extension into the trigone, as well as prostatic involvement, made complete surgical resection an unlikely option. Medical
management (chemotherapy) was discussed, but an acute response permitting urination was unlikely. The owner declined radiation
therapy due to the extent of the disease and the potential for significant side effects.
The owner chose urethral stenting, which is a rapid, effective, minimally invasive out-patient procedure shown to provide
immediate relief of stranguria by rapid restoration of a patent urethra.