Differential Diagnosis for 5 Month Old Infant with Projectile Vomiting, Gelly Like Diarrhea, and Poor Feeding

• Single Most Likely Diagnosis
  • Gastroesophageal reflux disease (GERD) with possible superimposed viral gastroenteritis: This is a common condition in infants that can cause projectile vomiting and is often associated with feeding difficulties. The addition of gelly like diarrhea could suggest a viral infection complicating the primary condition.
• Other Likely Diagnoses
  • Viral gastroenteritis: This is a common cause of diarrhea and vomiting in infants. The presence of gelly like diarrhea could be indicative of a specific viral etiology.
  • Lactose intolerance or cow's milk protein allergy: These conditions can cause similar symptoms, including diarrhea and vomiting after feeding, especially if the infant is formula-fed or has recently been introduced to cow's milk products.
  • Pyloric stenosis: Although typically presenting with projectile vomiting after feeding, it's less commonly associated with diarrhea. However, it remains a consideration in infants with persistent vomiting.
• Do Not Miss Diagnoses
  • Intussusception: A condition where a part of the intestine slides into an adjacent part, which can cause severe vomiting, diarrhea (sometimes with blood and mucus, giving a "currant jelly" appearance), and abdominal pain. It's a surgical emergency.
  • Volvulus or intestinal obstruction: These conditions can cause severe vomiting and abdominal distress. Diarrhea might not always be present, but the severity of symptoms warrants consideration.
  • Infections (bacterial or parasitic): Certain infections can cause severe gastrointestinal symptoms, including diarrhea and vomiting. Examples include Salmonella, Shigella, or Giardia infections.
• Rare Diagnoses
  • Congenital infections or metabolic disorders: Conditions such as congenital adrenal hyperplasia or other metabolic disorders can present with nonspecific symptoms including vomiting and diarrhea.
  • Food protein-induced enterocolitis syndrome (FPIES): A rare condition that can cause severe vomiting, diarrhea, and abdominal distress after ingestion of specific food proteins, often several hours after feeding.