atresie

Atresia is the congenital or acquired absence or abnormal closure of a normal body opening, duct, or canal, resulting in obstruction of passage. Congenital atresias arise during embryonic development and may involve various organ systems; acquired forms can result from inflammation, scarring, or trauma.

Common congenital sites include biliary atresia (obliteration of extrahepatic bile ducts), choanal atresia (blockage of the nasal passages at the back of the nasal cavity), intestinal atresias (such as duodenal, jejunal, ileal, or colonic), anorectal atresia, and, less frequently, vaginal or aural canal atresias. The underlying causes often involve failures in recanalization during development or vascular disruptions; atresias can occur as isolated conditions or as part of syndromes such as VACTERL or CHARGE.

Clinical features depend on the site. Biliary atresia presents with progressive jaundice in infancy and pale stools. Choanal atresia causes neonatal respiratory distress that may worsen when feeding and improve with crying. Intestinal atresias typically cause immediate postnatal vomiting and abdominal distension. Anorectal atresia presents with absent anal opening, and vaginal atresia may present in adolescence with primary amenorrhea or dyspareunia.

Diagnosis relies on clinical examination and imaging, including ultrasound or MRCP for biliary atresia, and abdominal radiography for intestinal atresias. Surgical exploration is often diagnostic and therapeutic.

Treatment is largely surgical and site-specific. Biliary atresia is managed with Kasai portoenterostomy, ideally before about 60 days of life. Intestinal and anorectal atresias require resection with anastomosis or staged procedures. Choanal and vaginal atresias require corrective procedures to restore patency. Prognosis varies widely with site, severity, and associated anomalies.