Ruptured Bladder & Uroperitoneum

There are several causes of uroperitoneum in the neonatal foal. Ruptured bladder is the most common. Urachal rents (tears) can also produce uroperitoneum. Congenital or traumatic lesions of the ureter may produce uroperitoneum or retroperitoneal urine accumulation [1].

I. Ruptured Bladder

1. History

1. Male & female foals.
2. Clinical signs develop by less than 7 days of age, usually after Day 2.
3. Foal appears normal at birth.

1. Exception is megavesica secondary to umbilical cord torsion and obstruction of urachus [2]. Signs seen at birth.

4. In some hypoxic ischemic encephalopathy (HIE) foals occurs because for a period of time foals don’t perceive bladder as full.
   Editor's Comment - always check the bladder with ultrasound on HIE foals.

2. Clinical Signs [3-5]

1. Depression, gradual anorexia (milk may accumulate on foal's head from mammary gland dripping).
2. ± abdominal pain, usually mild.
3. Abdominal distension (uroperitoneum) - may feel percussion waves across abdomen; rapid shallow breathing.
4. Intestinal ileus.
5. Dysuria and/or stranguria (dorsal-ventral flexion of the back and legs extended caudally), decreased frequency and volume of urine.
6. Dribbling urine.
7. Some septicemic foals develop ruptured bladder associated with cystitis.

3. Diagnosis

1. History and clinic signs.
2. Abdominal ultrasonography

1. Free peritoneal fluid.
2. Inability to identify intact bladder.

3. Abdominal paracentesis - large volume of fluid. May occasionally smell like ammonia.
4. Compare serum creatinine vs. that in peritoneal fluid.

1. If abdominal fluid is urine, creatinine measured in peritoneal fluid should be higher (1.75 - 2X) than that of serum.
2. BUN is not as reliable due to equilibration with plasma.
3. K+ in serum compared to peritoneal fluid is not reliable.
4. Foals may or may not be azotemic.

5. Retrograde injection of new methylene-blue into bladder and look for dye in peritoneal fluid via paracentesis [5].
   Editor's Comment - Make sure new methylene-blue is sterile.
6. Contrast bladder radiography - use aqueous based organic iodine solutions.
7. Blood gas and electrolyte imbalances (hyponatremia, hypochloremia, hyperkalemia and acidosis).

1. These may be seen with conditions other than ruptured bladder.
2. Electrolytes may be normal if foal has been on IV fluids.

4. Differential

1. Most often confused with septic foal or neurologic case when presented in semi coma.
2. Hyponatremia may produce neurologic symptoms.

5. Subcutaneous rupture of the urachus [6].

1. Fluctuant non painful swelling in umbilical region noted at 5-30 hours of age.
2. Differentiate from hernia because cannot reduce this swelling with palpation.
3. Aspirated fluid has increased creatinine or BUN.
4. Urine may be confined to subcutaneous tissue or dissect to peritoneum and cause uroperitoneum.
5. Prompt surgical correction indicated.

II. Urachal Rent and Uroperitoneum

1. History and clinical signs are similar to ruptured bladder.
2. Concurrent infection of the urachus.

1. Associated with septicemia, prematurity, or ICU foal.
2. Associated with patent urachus.
3. Associated with urachal infection and cystitis.

3. Peritoneal fluid

1. Inflammatory cells and increased protein.
2. Creatinine - is 2X that of serum creatinine.

4. Treatment is immediate surgical correction and aggressive antibiotic therapy and nursing care; plasma transfusion, etc.
5. Ureter stenosis and ureter defect has been described as a cause of uroperitoneum in a foal [7].

III. Ruptured Bladder Treatment - Medical

1. Nonsurgical

1. Small leaks have been managed with an indwelling urinary catheter [8] (Levine naso-gastric tube) especially if foal has other problems and is a surgical risk (respiratory problems-pneumonia).
2. Hyperkalemia can cause death; Do not administer K+ containing antibiotics or I.V. fluids (use 0.9% saline).

IV. Surgical Considerations [9]

1. Necessary for all large defects in the bladder or urachus.
2. Detailed surgical description can be found in Reference [9].
3. Replace and correct fluid, electrolyte and blood gas abnormalities before anesthetic induction [10,11].
4. Slowly draining urine from abdomen before surgery is controversial. Foals have developed peritonitis from this effort; conversely rapid loss of fluid from abdomen during surgery may potentiate shock.
5. Incision is made 2-3 cm paramedian to prepuce or prepuce can be reflected and incisions made on midline.
6. If urachus is the site of the tear, remove along with umbilicus and use Parker-Kerr over sew with Vicryl®.
7. Tears are usually located dorsally on the bladder.
8. If tear is not easily visible, bladder can be distended with a pre-placed urinary catheter (Levine tube). Leave tube in place 2-3 days post-surgically.
9. Drain urine off slowly, if not accomplished before surgery.
10. Use Vicryl® Ethicon Sutures (absorbable) in bladder. Non-absorbable sutures serve as nidus for stones and infection.
11. Post operative care -Leave catheter in bladder if not voiding urine post-surgically. Some foals may need 2-5 days of catheterization because they do not perceive bladder distension. That is how it ruptured in the first place in some foals.

V. Prognosis

1. In non-infected foals outcome is good.
2. In those with concurrent infection or other gastrointestinal problems - 50% survival [5].
3. Repeat rupture in some foals- need catheterization – some for 7 days.