Differential Diagnosis
- Single most likely diagnosis
- A) Aganglionic colon: This condition, also known as Hirschsprung's disease, is characterized by the absence of ganglion cells in the distal colon and rectum, leading to a functional obstruction. The symptoms of not having a bowel movement for 4 days, the last stool being dark green and sticky, and the barium enema showing a small rectum and distal colon are consistent with this diagnosis.
- Other Likely diagnoses
- B) Functional constipation: Although less likely given the age of the patient and the specific findings on the barium enema, functional constipation could still be considered, especially if the patient's diet or feeding schedule is contributing to hard stools.
- Do Not Miss
- D) Intussusception: Although the patient does not have the typical presentation of intussusception (which includes vomiting, abdominal pain, and currant jelly stool), it is a condition that can cause intestinal obstruction and must be considered due to its potential severity.
- E) Meconium ileus: This condition, associated with cystic fibrosis, presents with intestinal obstruction in the newborn period and could be considered, especially given the sticky, dark green stool, which might suggest meconium.
- Rare diagnoses
- C) Inflammatory bowel disease: This is highly unlikely in a 7-day-old infant, as inflammatory bowel disease typically presents later in life.
- F) Pyloric stenosis: This condition causes vomiting and typically presents with a palpable mass in the upper abdomen, which does not match the patient's symptoms or examination findings.