Bladder, Urethra and Ureters
Ruptured bladders- foals
We believe 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.
Diagnostics
Foals are typically normal at birth, with no signs of illness for 24-48 hours. They then become lethargic with a decreased interest in suckling. Some foals will become colicky (show signs of abdominal pain). Many can urinate normally. Occasionally a foal will be anuric or void only small volumes of urine.
Abdominal distension develops over time.
Foals will be tachycardic. Some foals will develop pleural effusion and tachypnea.
Treatment
Stabilization prior to surgery is required:
- Electrolyte and fluid shifts should be corrected. Uncontrolled hyperkalemia can lead to death due to arrhythmias.
- Oxygenation can be impaired if the thoracic or abdominal cavities contain fluid that restricts diaphragmatic function. Urine should be drained from the abdomen/thorax to enable better ventilation and to remove the toxins. Nasal oxygen can also be given as a supplemental treatment.
- Dehydration needs to be addressed via iv fluids. Careful attention to the electrolyte imbalances. Remember, many fluids contain potassium and/or lactate. Typically, sodium chloride and sodium bicarbonate are given iv (avoid LRS due to the potassium in the fluid). Dextrose and insulin are administered to drive potassium into the cells where it is safely sequestered (0.5 g dextrose/kg bwt; 0.1 unit insulin/kg bwt iv).
Surgery
Bladder repair in foals is performed under general anesthesia. The foal should have a normal temperature, glucose, hydration levels and a potassium is <5.5 mEq/L before anesthesia and surgery is performed. 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).
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.
Key Takeaways
- 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.
- 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!
