Differential Diagnosis for a 3-Week-Old Olive-Shaped Mass and Vomiting
Single Most Likely Diagnosis
- Pyloric Stenosis: This condition is characterized by the thickening of the pylorus muscle, leading to gastric outlet obstruction. The olive-shaped mass is a classic finding, and vomiting is a common symptom. The age of the patient and the description of the mass make this diagnosis highly likely.
Other Likely Diagnoses
- Gastroesophageal Reflux Disease (GERD): While GERD can cause vomiting, it might not directly explain the olive-shaped mass. However, it's a common condition in infants and could be considered if the mass is not typical of pyloric stenosis.
- Intussusception: This is a condition where a part of the intestine slides into an adjacent part, potentially causing a palpable mass and vomiting. It's more common in older infants but can occur at any age.
- Hypertrophic Gastric Pyrosis: Though less common, this condition involves thickening of the gastric pylorus similar to pyloric stenosis but might not present with the classic olive-shaped mass.
Do Not Miss Diagnoses
- Intestinal Obstruction: This could be due to various causes such as volvulus, atresias, or meconium ileus, especially in newborns. The vomiting could be bilious, indicating an obstruction.
- Appendicitis: Although rare in infants, appendicitis can present with vomiting and abdominal pain. A palpable mass might be felt if the appendix is enlarged.
- Incarcerated Hernia: An inguinal hernia that becomes incarcerated can cause vomiting and a palpable mass, and it's a surgical emergency.
Rare Diagnoses
- Neuroblastoma: A rare tumor that can present as an abdominal mass. While it's less likely to cause vomiting as a primary symptom, it's a critical diagnosis not to miss due to its potential for malignancy.
- Wilms Tumor: Another rare abdominal tumor that could potentially cause a palpable mass and vomiting, though it's more commonly associated with hematuria and hypertension.
- Congenital Anomalies: Various congenital anomalies of the gastrointestinal tract, such as duplications or cysts, could potentially cause a mass and vomiting, though these are rare and often diagnosed prenatally or shortly after birth.