Neonatal Surgery
Bilious vomiting in the neonate
Bilious vomiting at any neonatal age is malrotation with midgut volvulus until excluded. The diagnostic study is an upper GI contrast series, not a contrast enema; look for a duodenojejunal junction that fails to cross the midline and lies below the duodenal bulb. Treatment is an urgent Ladd procedure. A normal abdominal radiograph does not exclude volvulus.
Other must-know entities include duodenal atresia (double bubble, no distal gas, associated with Down syndrome and VACTERL), jejunoileal atresia (multiple air-fluid levels from a prenatal vascular accident), meconium ileus (cystic fibrosis, microcolon, Neuhauser sign), Hirschsprung disease (delayed meconium, transition zone, acetylcholinesterase-positive rectal biopsy), necrotising enterocolitis (Bell staging: pneumatosis is IIA, portal venous gas IIB, pneumoperitoneum IIIA and operative), and oesophageal atresia with tracheo-oesophageal fistula (excessive secretions, coiled nasogastric tube, nothing by mouth, suction decompression, echocardiography before repair).
Traps
Pyloric stenosis presents at 3-6 weeks with non-bilious projectile vomiting and a hypochloraemic hypokalaemic metabolic alkalosis with paradoxical aciduria - do not expect bilious emesis. In necrotising enterocolitis a deceptively well-looking infant with a new pneumoperitoneum still needs surgery or a drain. In CDH, avoid vigorous bag-mask ventilation; use a Replogle tube and gentle ventilation.
Worked example
A 5-day-old has bilious emesis, a soft abdomen and a normal radiograph. Rule of thumb: under one month plus bilious vomit equals urgent upper GI series; a corkscrew appearance means theatre.