The first differential diagnoses I would suggest for the three-month-old infants is pyloric stenosis. Pyloric stenosis is seen frequently in pediatric patients and is a progressive hypertrophy of the pylorus due to gastric outlet blockage (Hiller, Petty, & Sieren, 2015). It is when food is prevented from entering the small intestine because of the pylorus muscle. The symptoms of pyloric stenosis can start anywhere from one week to five months and include postprandial vomiting, which is sometimes projectile, abdominal pain, dehydration, frequent hunger and lack of weight gain (Medline Plus, 2017). These symptoms are similar to the three-month-old baby and would fit his diagnosis best.
The next differential diagnoses would be Gastroesophageal
The next differential diagnoses would be Gastroesophageal