Urachus: patent

Urachal fistula

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  • Cause : congenital and acquired forms of failure of the urachus to occlude at the umbilicus.
  • Acquired types may be associated with systemic debilitation and/or umbilical infection.
  • Signs : Presents within first 2 weeks of life with moist umbilicus and leakage of urine from the patent urachus.
  • In acquired forms may be severe systemic signs in compromised neonatal foal.
  • Diagnosis : history, signs.
  • Treatment : is usually medical with antibiotic therapy, local umbilical cleaning/skin protection, possibly cautery, primary problem care and surgical resection of the umbilical remnants with persistent cases.
  • Prognosis : guarded in systemically ill foals.


Differential diagnosis

  • Ruptured bladder syndrome    .
  • Septic omphalitis .
  • Uroperitoneum    due to rupture of the urachus or bladder within the abdomen and leakage of fluid into the subcutaneous tissue through the inguinal canal.
  • Extraperitoneal rupture of the penile urethra .


Clinical signs

  • Moist umbilicus with drips, leaks or streams may or may not be associated with micturition.
  • Septic omphalitis with swelling and pain in some cases.
  • Secondary symptoms are seen in compromised debilitated neonatal foals.
  • Subcutaneous and/or abdominal muscle leakage of urine from urachus leads to swelling and cellulitis of the ventral abdominal wall.
  • Umbilical ring is normal.



  • Good if primary urachal fistula.
  • Guarded for septic omphalitis or debilitated foal.

Reasons for treatment failure

  • Failure to spontaneously close.
  • Poor for foals with septicemia    or systemic diseases.
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