Differential Diagnosis for Vomiting in a 3-Month-Old
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 symptoms often peak around 4 months of age, but can start as early as a few weeks old.
Other Likely Diagnoses
- Viral gastroenteritis: This is a common cause of vomiting in infants, often accompanied by diarrhea and fever.
- Overfeeding or feeding intolerance: Infants may vomit if they are overfed or have difficulty digesting certain formulas or breast milk.
- Pyloric stenosis: Although less common, this condition, which involves narrowing of the pylorus (the passage between the stomach and small intestine), can cause projectile vomiting in infants, typically starting around 3 weeks of age.
- Food allergy or intolerance: Allergies to proteins in formula or breast milk can cause vomiting, along with other symptoms like rash or diarrhea.
Do Not Miss Diagnoses
- Intussusception: A condition where a part of the intestine slides into another, which can cause severe vomiting, abdominal pain, and bloody stools. It's a medical emergency.
- Volvulus: A twisting of a portion of the intestine that can cut off blood flow, leading to severe vomiting, abdominal pain, and potentially life-threatening complications.
- Hirschsprung's disease: A congenital condition affecting the large intestine, leading to severe constipation or intestinal obstruction, which can cause vomiting.
- Inborn errors of metabolism: Certain metabolic disorders can present with vomiting, among other symptoms, and require prompt diagnosis and treatment to prevent serious complications.
Rare Diagnoses
- Congenital anomalies of the gastrointestinal tract (e.g., esophageal atresia, duodenal atresia): These are rare conditions that can cause vomiting due to obstruction or other functional issues.
- Neurological conditions (e.g., increased intracranial pressure, hydrocephalus): Although rare, neurological issues can cause vomiting in infants, often accompanied by other symptoms like lethargy, seizures, or abnormal head size.
- Endocrine disorders (e.g., congenital adrenal hyperplasia): Certain endocrine conditions can lead to vomiting among a constellation of other symptoms, including electrolyte imbalances and failure to thrive.