What is the cause of projectile vomiting in a 10-month-old infant?

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Last updated: March 26, 2025 • View editorial policy

Differential Diagnosis for Projectile Vomiting in a 10-Month-Old

Single Most Likely Diagnosis

  • Pyloric Stenosis: This condition is characterized by the thickening of the pylorus muscle, leading to gastric outlet obstruction. It typically presents with projectile vomiting in infants around 2-8 weeks of age, but can occasionally be seen in older infants. The classic presentation of projectile vomiting after feeding, along with a palpable "olive" mass in the right upper quadrant, makes it a prime consideration.

Other Likely Diagnoses

  • Gastroesophageal Reflux Disease (GERD): While GERD more commonly presents with regurgitation rather than projectile vomiting, it can cause significant discomfort and vomiting in infants. The diagnosis is often made based on clinical presentation and may require further testing for confirmation.
  • Infectious Gastroenteritis: Viral or bacterial infections can cause vomiting in infants. The presence of fever, diarrhea, or exposure to sick contacts can help support this diagnosis.
  • Food Protein-Induced Allergic Protocolitis (FPIAP) or Food Allergy: Allergic reactions to food proteins can cause vomiting, diarrhea, and blood in stool. A history of introducing new foods or a family history of allergies can increase suspicion.

Do Not Miss Diagnoses

  • Intussusception: Although more commonly associated with abdominal pain and bloody stools, intussusception can occasionally present with vomiting. It is a surgical emergency and must be considered, especially if there are signs of abdominal distress or blood in the stool.
  • Volvolus or Midgut Malrotation: These conditions involve twisting of the intestines and can lead to bowel obstruction. They are surgical emergencies and can present with bilious vomiting, abdominal distension, and signs of shock.
  • Ingestion or Poisoning: Accidental ingestion of toxins or medications can cause vomiting among other symptoms. A thorough history of potential exposures is crucial.

Rare Diagnoses

  • Congenital Anomalies (e.g., Duodenal Atresia, Tracheoesophageal Fistula): These conditions are typically diagnosed in the neonatal period but can occasionally present later with vomiting, especially if there are associated anomalies or if the condition was not previously diagnosed.
  • Metabolic Disorders: Certain metabolic disorders can present with vomiting, among other systemic symptoms. These are rare but important to consider, especially if there are other signs of illness or developmental delays.
  • Increased Intracranial Pressure: Conditions that increase intracranial pressure, such as hydrocephalus or brain tumors, can cause vomiting. This would be accompanied by other neurological signs such as lethargy, seizures, or focal neurological deficits.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.