Differential Diagnosis for a 4-day-old Infant with Bilious Vomiting
- Single most likely diagnosis:
- Intestinal obstruction (likely due to intestinal atresia or stenosis): This is the most likely diagnosis given the symptoms of bilious vomiting, abdominal distension, and the absence of stool since discharge, combined with the radiographic findings of dilated loops of bowel and air-fluid levels.
- Other Likely diagnoses:
- Pyloric stenosis: Although typically presents with non-bilious vomiting, it's a common cause of vomiting in infants and should be considered, especially if the vomiting becomes more frequent or persistent.
- Hirschsprung's disease: The presence of abdominal distension, tight anal canal, and the absence of stool since discharge make this a plausible diagnosis, as it involves a functional obstruction of the colon.
- Meconium ileus: This condition, often associated with cystic fibrosis, involves obstruction of the small intestine due to inspissated meconium and could present with similar symptoms.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed):
- Volvulus: A twisting of a portion of the intestine that can cut off blood supply, leading to tissue death. It's a surgical emergency and must be considered in any case of bilious vomiting in an infant.
- Intussusception: Although more common in older infants, it can occur in neonates and is a medical emergency requiring prompt diagnosis and treatment.
- Necrotizing enterocolitis: Although more typical in premature infants, it can occur in term infants and is a life-threatening condition that requires immediate attention.
- Rare diagnoses:
- Congenital intestinal lymphangiectasia: A rare condition involving dilation of lymphatic vessels in the intestines, which can lead to protein-losing enteropathy and intestinal obstruction.
- Chronic intestinal pseudo-obstruction: A rare condition characterized by recurrent episodes of intestinal obstruction without any mechanical cause, which can present in the neonatal period.