Differential Diagnosis for a 14-year-old presenting to the ER

• Single most likely diagnosis:
  • Appendicitis: This is a common cause of acute abdominal pain in adolescents, often presenting with pain that initially is diffuse or around the navel and then localizes to the lower right abdomen.
• Other Likely diagnoses:
  • Gastroenteritis: Viral or bacterial infections can cause stomach pain, vomiting, and diarrhea, common in adolescents.
  • Urinary Tract Infection (UTI): Can cause abdominal pain, especially in the lower abdomen, along with symptoms like dysuria and frequent urination.
  • Constipation: A frequent cause of abdominal pain in children and adolescents, often accompanied by changes in bowel habits.
  • Ovarian torsion or ovarian cyst (in females): These conditions can cause severe, sudden abdominal pain and are gynecological emergencies.
• Do Not Miss diagnoses:
  • Ectopic pregnancy (in sexually active females): Although less common, it's crucial to consider due to its severe consequences if missed.
  • Intussusception: A condition where a part of the intestine slides into an adjacent part, potentially cutting off blood supply, which requires immediate medical attention.
  • Testicular torsion (in males): A surgical emergency that causes severe testicular pain and can lead to loss of the testicle if not promptly treated.
  • Pneumonia or lower lobe pneumonia: Can sometimes present with abdominal pain, especially if the diaphragm is irritated.
• Rare diagnoses:
  • Inflammatory bowel disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause chronic abdominal pain, diarrhea, and other symptoms.
  • Pancreatitis: Inflammation of the pancreas, which can cause severe abdominal pain, more commonly associated with gallstones or alcohol use in adults but can occur in adolescents due to various reasons.
  • Hepatitis: Inflammation of the liver, which can cause abdominal pain, jaundice, and other symptoms, and can be due to viral infections, drugs, or other causes.