Bladder, Urethra and Ureters
Ruptured bladders
Ruptured bladders are most common in neonatal colts and in ruminants with urolithiasis. Ruptured bladders are unusual in camelids and swine. In adult horses, ruptured bladders are generally associated with parturition and are not common.
It is suspected that compression of full fetal bladder in the pelvic canal during parturition leads to an outflow obstruction; a rupture may also occur secondarily to necrosis of the bladder wall. Colts are more likely than fillies to develop ruptured bladders during parturition. The longer narrow urethra means the squeeze of parturition is more likely to rupture the bladder than to express the bladder. The bladder generally ruptures on the dorsal surface. Foals are often normal for the first day but then develop signs of uroabdomen.
Ruminants with obstructed urethras may rupture either the bladder or the urethra. When the bladder ruptures, the fluid leaks into the peritoneal cavity. Over time, the abdomen becomes distended a fluid wave can be detected. When the urethra ruptures, the fluid leaks subcutaneously along the ventral abdomen creating a large ventral plaque. Urine is irritating so signs of inflammation will be detected early with urethral rupture; later necrosis is more evident.
Treatment
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- drain the urine out of the peritoneal cavity
- repair the bladder surgically or keep the bladder decompressed so it can heal via second intention (this may require a PU)
- manage the inflammation, uremia and electrolyte disturbances
Because these are neonatal and/or sick animals, anesthesia can be tricky. If the animal has high potassium when it is anesthetized, it can lead to fatal arrhythmias. Oxygenation can be impaired if the thoracic or abdominal cavities contain fluid that restricts diaphragmatic function. Dehydration needs to be managed without causing more fluid accumulation and with careful attention to the electrolyte imbalances. Remember, many fluids contain potassium and/or lactate. Note: hyperkalemia is less marked and less common in ruminants.
For neonate sedation concerns, go back to the earlier drug chapters for more resources.
Preoperative care should include tetanus toxoid, perioperative antibiotics and analgesics and bladder catheterization.
With the patient in dorsal recumbency, a ventral midline approach to the bladder is performed. The penis and prepuce are reflected off midline. Umbilical structures are removed in the approach. The tear is usually found on the dorsal surface of the bladder at the trigone as this is a weak spot. Debridement of the tear margins are not usually required; bladders heal well and quickly.
In large animal species, we recommend a two layer closure of the bladder. Both layers are typically inverting patterns to minimize suture in the lumen (a nidus for stone formation) and suture exposed to the peritoneal cavity (a risk factor for adhesions). The most common is a Cushings pattern with 2-0 absorbable suture that dissolves fairly rapidly. Dexon dissolves in urine and should not be used.
The abdomen is flushed and the abdominal wall closed routinely (typically #1 absorbable suture, simple continuous pattern).
In beef cattle with ruptured bladder secondary to urolithiasis, the bladder is left to heal by second intention (urinary catheter placed via urethrotomy to keep urine drained out).
Postoperative care
- Antibiotics are administered for 3-5 days unless the patient is sick.
- Low level anti-inflammatories are given (watch for gastric ulcers and treat with omeprazole).
- Monitor for complications of celiotomy: peritonitis, adhesions, incisional infections
- The most common complication is recurrence of the uroabdomen. This may be due to leakage through the bladder wall or incision. Many can be managed with bladder catheterization rather than repeat laparotomy.
Prognosis
Prognosis is surprisingly good. Anesthesia is the risky part. Foals recover well and seem to have no related problems. Goats need to have the cause of the obstruction fixed as well as the ruptured bladder. Large ruminants are generally managed conservatively until slaughter is possible. Steers with a serum phosphate >2.9 mmol/L are associated with longer duration ruptures and have poorer prognosis.
Key Takeaways
- Ruptured bladders occur most commonly in male foals (~ 2 days of age) and in ruminants with urolithiasis.
- Peritoneal creatinine 2x serum creatinine = urine. A quick test is to heat the sample and sniff.
- Foals should be referred to a hospital equipped to manage the hyperkalemia and anesthetic risk. These animals must be stabilized – eg get K < 5.5 prior to anesthesia. Medical emergency, not surgical emergency.
- Prognosis is good for foals. Prognosis is not as good for animals with urolithiasis.
- Keep suture out of bladder (use cushing or lembert); otherwise it becomes a nidus for stone formation
Resources
Ebook Anesthesia chapter _- see Foal resources section at bottom of page
Common fluid types in vet med -note: we carry saline, LRS and sterile water/dextrose.
Neonates and Periparturient Mares, Vet Clin Equine 39 (2023) 351–379
Bladder ruptures, AAEP- client friendly version
Conservative management of a ruptured bladder in a gelding, 2019 EVE – good review of principles that can apply across species
Youtube video-Ruptured bladder in a foal at Upstate Equine Medical Center
Study break- be proud!
