Differential Diagnosis for a 4-week-old Boy with Vomiting
- Single most likely diagnosis
- Pyloric Stenosis: This condition is characterized by the thickening of the pylorus muscle, leading to gastric outlet obstruction. The symptoms of projectile vomiting after feedings, a palpable mass in the epigastrium (often referred to as an "olive"), and the age of the patient are all consistent with pyloric stenosis. The condition typically presents in infants around 3-6 weeks of age.
- Other Likely diagnoses
- Gastroesophageal Reflux Disease (GERD): Although GERD can cause vomiting, it typically does not present with the forceful, projectile vomiting seen in pyloric stenosis. However, it remains a consideration, especially if the vomiting is less severe and accompanied by other symptoms like arching of the back or fussiness during feedings.
- Infectious Gastroenteritis: This could cause vomiting, but the absence of fever, diarrhea, or exposure history makes it less likely. The vomiting in gastroenteritis is often accompanied by other symptoms such as fever and diarrhea.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Intussusception: Although less common in this age group and typically presenting with bloody stools, intussusception can cause vomiting and abdominal masses. It's a surgical emergency and must be considered, especially if there's any change in stool character or if the patient's condition worsens.
- Volvolus or Other Surgical Abdominal Emergencies: Conditions like midgut volvulus can present with vomiting and abdominal signs. These are rare but critical diagnoses that require immediate surgical intervention.
- Rare diagnoses
- Congenital Anomalies (e.g., Duodenal Atresia, Tracheoesophageal Fistula): These conditions can cause vomiting but are typically identified earlier in life or have other distinguishing features such as polyhydramnios in the prenatal period or respiratory symptoms.
- Metabolic Disorders: Certain metabolic disorders can present with vomiting in the neonatal period, but they often come with other systemic signs or laboratory abnormalities that would prompt their consideration.