Urachal patency is an umbilical disease in newborn foals. Etiologically, either the closure of the urachus remains absent after birth (persistent urachus) or the urachus was already closed and reopens at a later time (patent urachus). The most common causes of patent urachus are congenital defects, tearing of the navel above the predilection site, trauma, increased intravesical or abdominal pressure and umbilical infections. Patent urachus occurs more frequently in premature or weak and immunocompromised foals. Colts are more often affected than fillies. Typical clinical signs are apparent immediately after birth (persistent urachus) or 7-14 days postpartum (patent urachus). These include either dripping or a stream of urine through umbilicus during micturition as well as a moist umbilical area. The diagnosis is usually unambiguous. Typical laboratory findings are not described for patent urachus. Conservative treatment such as obliteration, cauterization or cryosurgery may be employed in cases lacking an inflammation of the urachus or other umbilical structures and when the urachal lumen measures less than 6 mm. Surgical treatment is indicated in foals with large urachal lumen, an umbilical infection or sepsis as well as when no therapeutic success is attained after a conservative treatment of 5-7 days. In most cases, prognosis is good, however complications such as umbilical inflammation, disseminating infections, and secondary joint diseases may significantly impair prognosis.
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