Differential Diagnosis for 13-year-old Male with Chronic Intermittent Abdominal Pain

• Single Most Likely Diagnosis
  • Irritable Bowel Syndrome (IBS): This is a common condition in adolescents characterized by chronic abdominal pain, changes in bowel habits (such as diarrhea or constipation), and poor appetite. The absence of constipation on the KUB (Kidneys, Ureters, Bladder) X-ray and the presence of diarrhea and poor appetite align with IBS symptoms.
• Other Likely Diagnoses
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic abdominal pain, diarrhea, and changes in appetite. Although less common than IBS, they are important to consider due to their significant impact on quality of life and the need for specific management.
  • Functional Dyspepsia: This condition involves recurring signs and symptoms of indigestion that have no obvious cause. Symptoms can include pain or discomfort in the upper abdomen, which might be accompanied by nausea, bloating, or changes in appetite.
• Do Not Miss Diagnoses
  • Appendicitis: Although the pain is described as intermittent, appendicitis can sometimes present with recurring or intermittent pain before becoming constant. Missing this diagnosis could lead to severe consequences, including perforation and peritonitis.
  • Intestinal Obstruction: This is a blockage that prevents the normal flow of the products of digestion (including food, fluid, and gas) in the intestines. It can cause severe abdominal pain, vomiting, and changes in bowel habits. Early diagnosis is crucial to prevent complications.
  • Peptic Ulcer Disease: Ulcers in the stomach or duodenum can cause chronic or intermittent abdominal pain, often related to eating. While less common in adolescents, they can occur and require specific treatment to heal and prevent complications.
• Rare Diagnoses
  • Celiac Disease: An autoimmune disorder where the ingestion of gluten leads to damage in the small intestine, causing abdominal pain, diarrhea, and malabsorption. It's less common but should be considered, especially with chronic gastrointestinal symptoms.
  • Chronic Intestinal Pseudo-obstruction: A rare condition characterized by impairment of the muscle contractions that move food, fluid, and air through the intestines, leading to symptoms similar to those of a true obstruction.
  • Eosinophilic Gastroenteritis: A rare condition involving eosinophilic infiltration of the gastrointestinal tract, leading to abdominal pain, nausea, vomiting, and diarrhea. It's an important consideration in patients with atopic diseases or when other diagnoses are ruled out.