Differential Diagnosis for a 6-month-old with Vomiting

Single Most Likely Diagnosis

• Gastroesophageal reflux disease (GERD): This is a common condition in infants, characterized by the backflow of stomach contents into the esophagus, leading to vomiting. The age of the patient and the symptom of vomiting make GERD a highly plausible diagnosis.

Other Likely Diagnoses

• Viral gastroenteritis: This is a common cause of vomiting in infants, often accompanied by diarrhea and fever. The contagious nature and prevalence of viral gastroenteritis in this age group make it a likely consideration.
• Overfeeding or feeding intolerance: Infants may vomit if they are overfed or if they have difficulty digesting certain components of their formula or breast milk. This is a common issue that can be easily addressed by adjusting feeding practices.
• Pyloric stenosis: Although less common, pyloric stenosis is a condition where the pylorus (the passage between the stomach and small intestine) thickens, causing projectile vomiting. It typically presents in infants around this age.

Do Not Miss Diagnoses

• Intussusception: A serious condition where a part of the intestine slides into an adjacent part, potentially cutting off blood flow. It's a medical emergency that can cause vomiting, abdominal pain, and bloody stools.
• Volvulus: A condition where the intestine twists, cutting off its blood supply. It's a surgical emergency that can present with vomiting, abdominal pain, and sometimes bloody stools.
• Ingestion or poisoning: Infants are prone to putting objects in their mouths, and ingestion of toxic substances can lead to vomiting among other symptoms. Prompt identification and treatment are crucial.

Rare Diagnoses

• Metabolic disorders: Certain metabolic disorders can present with vomiting in infancy. These are rare but critical to diagnose early for proper management.
• Congenital anomalies of the gastrointestinal tract: Conditions like esophageal atresia, tracheoesophageal fistula, or duodenal atresia can cause vomiting. Although these are typically diagnosed in the neonatal period, some cases might not be immediately apparent.
• Meningitis: Although more commonly associated with fever, headache, and stiff neck in older children and adults, meningitis can present with vomiting in infants, especially if they are too young to express other symptoms.