Abdominal Pain Differential Diagnoses in Adults

Abdominal pain is a common symptom with a wide range of possible causes. The differential diagnosis can be organized into the following categories:

• Single Most Likely Diagnosis
  • Gastroenteritis: This is often the most common cause of abdominal pain in adults, typically presenting with diarrhea, vomiting, and fever. It's usually viral in nature and self-limiting.
• Other Likely Diagnoses
  • Irritable Bowel Syndrome (IBS): Characterized by chronic abdominal pain, bloating, and alteration of bowel habits without an identifiable cause. It's a common condition that affects a significant portion of the adult population.
  • Inflammatory Bowel Disease (IBD): Includes conditions like Crohn's disease and ulcerative colitis, which cause chronic inflammation of the gastrointestinal tract. Symptoms can include abdominal pain, diarrhea, weight loss, and fatigue.
  • Peptic Ulcer Disease: Gastric and duodenal ulcers can cause epigastric pain, especially after eating or at night, and are often associated with Helicobacter pylori infection or NSAID use.
  • Constipation: Can cause significant abdominal discomfort and is often associated with changes in bowel habits, straining during bowel movements, and hard or lumpy stools.
• Do Not Miss Diagnoses
  • Appendicitis: Although not the most common cause, appendicitis is a surgical emergency that requires prompt diagnosis and treatment to prevent perforation and peritonitis. It typically presents with right lower quadrant pain, fever, and leukocytosis.
  • Ectopic Pregnancy: A life-threatening condition in women of childbearing age, presenting with abdominal pain, vaginal bleeding, and a positive pregnancy test. It requires immediate medical attention.
  • Mesenteric Ischemia: A condition where there's insufficient blood flow to the intestines, which can lead to bowel infarction. It presents with severe abdominal pain out of proportion to physical examination findings, and risk factors include atrial fibrillation, heart failure, and recent surgery.
  • Ruptured Aortic Aneurysm: A catastrophic condition presenting with severe, tearing abdominal pain, often radiating to the back, and can lead to shock and death if not promptly treated.
• Rare Diagnoses
  • Intussusception: A condition where a part of the intestine telescopes into another part, which can cause bowel obstruction and ischemia. It's more common in children but can occur in adults, often associated with a lead point like a tumor.
  • Celiac Disease: An autoimmune disorder that causes the immune system to react to gluten, leading to small intestine damage and malabsorption. It presents with chronic diarrhea, abdominal pain, and weight loss.
  • Porphyrias: A group of rare genetic disorders that can cause acute intermittent porphyria, leading to severe abdominal pain, neurological symptoms, and psychological disturbances.
  • Abdominal Migraine: A condition that presents with recurrent episodes of severe abdominal pain, often accompanied by other migraine symptoms like headache and nausea, more commonly seen in children but can persist into adulthood.