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Basics ⬇

Outline

BASICS

Overview!!navigator!!

The urachus is the umbilical structure that directs urine from the fetal bladder to the allantoic fluid. The urachus normally closes at the time of birth, but it can remain patent or reopen secondary to inflammation or infection. The urachus that fails to close within hours of birth (congenital) or that begins to leak urine after it has initially closed (acquired) is considered a patent urachus.

Signalment!!navigator!!

  • Neonatal foals are affected by this condition
  • There does not appear to be a breed or sex predilection

Signs!!navigator!!

  • Urine is seen streaming or dripping from the umbilicus when the foal urinates, or the umbilicus may be moist from urine leakage
  • When there is infection associated with a patent urachus, the umbilicus may also be enlarged, painful, or warm, and the foal may exhibit fever, lethargy, and poor appetite

Causes and Risk Factors!!navigator!!

  • Congenital factors such as excessive traction or twisting of the umbilical cord in utero may be related to congenital or persistent patent urachus
  • After parturition, omphalophlebitis can lead to reopening of the urachus

Diagnosis ⬆ ⬇

Outline

DIAGNOSIS

Differential Diagnosis!!navigator!!

Omphalophlebitis

CBC/Biochemistry/Urinalysis!!navigator!!

  • When patent urachus is complicated with omphalophlebitis, leukocytosis and hyperfibrinogenemia are often present
  • Occasionally, tears in the urachus can extend intra-abdominally and result in uroperitoneum. Azotemia, hyponatremia, and hyperkalemia may be seen in these cases

Imaging!!navigator!!

  • Ultrasonography can confirm patency between the bladder and the urachus, and can determine whether omphalophlebitis or urachal abscess is present
  • Positive-contrast radiography—contrast material delivered retrograde via the urethra can confirm patency between the bladder and the urachus and can also reveal any leakage from the urachus into the abdomen or subcutaneous tissues

Other Diagnostic Procedures!!navigator!!

  • Bacterial culture of the aseptically prepared umbilical stump if omphalophlebitis is suspected
  • Blood cultures should be performed in neonates to rule out septicemia

Treatment ⬆ ⬇

TREATMENT

  • The umbilicus should be kept clean by dipping in dilute chlorhexidine (0.5%) or dilute iodine (1%) twice daily until the umbilicus is no longer patent. Topical application of cauterizing compounds such as silver nitrate or strong iodine can be used for congenital uncomplicated patent urachus; however, these should never be used in cases of acquired patent urachus with omphalophlebitis
  • Nursing care should also include protection of the skin from urine scalding (e.g. with petroleum jelly)
  • Surgical resection of the umbilical remnants if infection is present with patent urachus or if the urachus has not closed after 5–7 days of medical treatment

Medications ⬆ ⬇

Outline

MEDICATIONS

Drug(s) of Choice!!navigator!!

  • Systemic antimicrobials are recommended for congenital and acquired patent urachus
  • Broad-spectrum antimicrobials—usually a penicillin and an aminoglycoside (e.g. amikacin), and treatment should be guided by culture and sensitivity from umbilical or blood cultures

Contraindications/Possible Interactions!!navigator!!

  • Aminoglycosides should be used with caution in foals with renal compromise or dehydration
  • Other broad-spectrum parenteral antimicrobial choices include ceftiofur (5–10 mg/kg IV or IM BID)

Follow-up ⬆ ⬇

Outline

FOLLOW-UP

Patient Monitoring!!navigator!!

  • Monitor for signs of systemic infection such as fever, lethargy, joint effusion, or lameness
  • Palpate umbilicus to detect any changes in size, consistency, or persistent urine leakage
  • Serial ultrasonographic examinations of the umbilical remnants can detect development of omphalophlebitis

Prevention/Avoidance!!navigator!!

  • Adequate colostrum
  • Clean environment
  • Avoid traction on the umbilicus during parturition
  • Umbilical disinfection

Possible Complications!!navigator!!

  • Ascending infection and bacteremia can lead to septic omphalophlebitis, septicemia, and septic arthritis
  • Treatment with cauterizing agents can lead to significant inflammation of the umbilicus, and can cause scalding of the ventral abdomen and prepuce if used incorrectly

Expected Course and Prognosis!!navigator!!

  • Most foals with congenital patent urachus will have resolution with medical management. If the urachus remains patent after 5–7 days of treatment or if there are signs of progressive infection, surgical removal of the umbilicus is recommended
  • Prognosis for congenital patent urachus is excellent. Prognosis for acquired patent urachus is good provided there are no secondary complications with infection
  • Septicemia and septic arthritis will greatly reduce the prognosis

Miscellaneous ⬆ ⬇

Outline

MISCELLANEOUS

Associated Conditions!!navigator!!

Omphalophlebitis

Age-Related Factors!!navigator!!

This is a condition of neonatal foals.

Suggested Reading ⬆ ⬇

Nolen-Walston R. Umbilical and urinary disorders. In: Paradis MR, ed. Equine Neonatal Medicine: A Case-Based Approach. Philadelphia, PA: Saunders, 2006:231–245.

Author(s) ⬆

Author: Margaret C. Mudge

Consulting Editor: Margaret C. Mudge