Differential Diagnosis for Abdominal Pain

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, especially if the pain is accompanied by symptoms like diarrhea, vomiting, and fever. The justification for this being the single most likely diagnosis is its high prevalence and the fact that it can affect anyone, regardless of age or health status.
• Other Likely Diagnoses
  • Irritable Bowel Syndrome (IBS): Characterized by chronic abdominal pain, bloating, and alteration of bowel habits in the absence of any mechanical, inflammatory, or biochemical abnormalities. IBS is common and should be considered in patients with recurrent abdominal pain without an obvious cause.
  • Urinary Tract Infection (UTI): Can cause abdominal pain, especially in the lower abdomen, and is often accompanied by dysuria, frequency, and urgency. UTIs are more common in women but can occur in anyone.
  • Inflammatory Bowel Disease (IBD): Includes conditions like Crohn's disease and ulcerative colitis, which can cause chronic abdominal pain, diarrhea, weight loss, and sometimes blood in the stool. The chronic nature and combination of symptoms make IBD a likely consideration.
• Do Not Miss Diagnoses
  • Appendicitis: Although not the most common cause, appendicitis is a medical emergency that requires prompt surgical intervention. It typically presents with severe abdominal pain that initially may be diffuse but often localizes to the right lower quadrant.
  • Ectopic Pregnancy: A life-threatening condition that should be considered in women of childbearing age presenting with abdominal pain, especially if there's a history of missed periods or positive pregnancy test.
  • Ruptured Aortic Aneurysm: Presents with severe, tearing abdominal pain and is a medical emergency. It's more common in older adults with a history of hypertension or smoking.
  • Mesenteric Ischemia: A condition where there's insufficient blood flow to the intestines, which can cause severe abdominal pain out of proportion to the physical examination findings. It's a medical emergency that requires prompt intervention.
• Rare Diagnoses
  • Intussusception: A condition where a part of the intestine telescopes into another part, which can cause abdominal pain, vomiting, and bloody stools. It's rare in adults but more common in children.
  • Porphyria: A group of disorders that can cause acute intermittent abdominal pain, among other symptoms. It's rare and often diagnosed after other causes have been ruled out.
  • Abdominal Migraine: A condition that causes recurrent episodes of severe abdominal pain, often accompanied by other migraine symptoms like headache or nausea. It's more common in children but can occur in adults.

Each of these diagnoses has distinct features and considerations, and a thorough history, physical examination, and sometimes diagnostic tests are necessary to determine the cause of abdominal pain.