Differential Diagnosis for Abdominal Distension in a Newborn
- Single most likely diagnosis:
- Meconium Ileus: This condition is characterized by the presence of thick, sticky meconium in the ileum, which is consistent with the findings during the emergency laparotomy. The absence of stool or gas in the rectum and the diffusely narrow appearance of the colon also support this diagnosis. Meconium ileus is often associated with cystic fibrosis.
- Other Likely diagnoses:
- Intestinal Obstruction: The presence of multiple dilated loops of small bowel and the lack of air in the large intestine and rectum suggest an obstruction. This could be due to various causes such as atresias, stenosis, or volvulus.
- Hirschsprung's Disease: Although less likely given the presence of thick, sticky stool, Hirschsprung's disease could still be considered, especially if the colon appears narrow. However, the primary issue in Hirschsprung's is the absence of ganglion cells in the distal colon, leading to a functional obstruction.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed):
- Necrotizing Enterocolitis (NEC): Although the patient's age and the presence of free air might suggest a perforation, NEC typically occurs in premature infants. However, it's crucial not to miss this diagnosis due to its high mortality rate.
- Volvolus or Midgut Volvulus: These conditions can cause intestinal obstruction and ischemia, leading to necrosis if not promptly treated. The presence of free air and the clinical presentation could be consistent with a volvulus, especially if there's a malrotation.
- Rare diagnoses:
- Meconium Plug Syndrome: This is a rare condition where a plug of meconium causes intestinal obstruction. It's less likely given the description of thick, sticky stool throughout the ileum.
- Congenital Aganglionic Megacolon (Total Intestinal Aganglionosis): An extremely rare form of Hirschsprung's disease where the entire intestine lacks ganglion cells. This would be an unusual presentation but could be considered with the narrow colon appearance.