Equis ISSN 2398-2977

Urachus: patent

Synonym(s): Urachal fistula

Contributor(s): Jonathan Pycock, Wendy E Vaala

Introduction

  • 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.

Pathogenesis

Etiology

  • Congenital or acquired.

Pathophysiology

Congenital urachus syndrome
  • Urachus never closes at birth.
  • Unknown etiology possibly due to distention from cord torsionin uteroor during delivery leading to tension of the umbilicus, dilation of the urachus and preventing occlusion.
    Acquired urachus syndrome
  • Re-opens post-partum as the dried umbilical stump falls off.
  • Associated with umbilical infection/inflammation or excessive use of concentrated iodine dip resulting in premature sloughing of umbilical stump.
  • Excessive wetness or trauma to the umbilical stump in the recumbent foal.
  • Prolonged recumbency in debilitated foal.
  • Poor/inexperienced cord ligation or severance. Ligature, if not removed may result in premature sloughing of stump.
  • Any cause of increased intra-abdominal pressure, eg meconium retention   Rectum: meconium impaction  (tenesmus, dysuria etc).
  • Urine leakage   →   persistent irritation and potential source of infection.
  • Congenital forms are present at birth.

Timecourse

  • Acquired forms develop in the first 2 weeks of life.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Smith M (2006)Management of umbilical disorders in the foal.In Pract28(5), 280-287 VetMedResource.
  • Reef V B, Collatos C, Spencer P A, Orsini J A and Sepsey L M (1989)Clinical, ultrasonographic, and surgical findings in foals with umbilical remnant infections.JAVMA195(1), 69-72 PubMed.
  • Reef V B and Collatos C (1988)Ultrasonography of umbilical structures in clinically normal foals.Am J Vet Res49(12), 2143-2146 PubMed.
  • Richardson D W (1985)Urogenital problems in the neonatal foal.Vet Clin North Am Equine Pract1(1), 179-188 PubMed.
  • Richardson D W & Kohn C W (1983)Uroperitoneum in the foal.JAVMA182(3), 267-271 PubMed.
  • Ford J & Lokai M D (1982)Ruptured urachus in a foal.Vet Med Small Anim Clin77(1) 94-95 PubMed.

Other sources of information

  • Barrelet A (1999)Investigation and management of foal umbilical disorders.In:Proc 38th BEVA Congress.pp8-10.


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