Abdominal Pain Differential Diagnosis

The differential diagnosis for abdominal pain is extensive and can be categorized into several groups. Here's a breakdown of the possible causes:

• 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 specific symptoms help differentiate IBD from other causes.
• 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, localized pain in the lower right abdomen, fever, and loss of appetite.
  • Ectopic Pregnancy: A life-threatening condition where the embryo implants outside the uterus, often causing severe abdominal pain, vaginal bleeding, and sometimes shoulder pain due to blood irritating the diaphragm. This diagnosis is critical in women of childbearing age.
  • Ruptured Aortic Aneurysm: Presents with severe, tearing abdominal pain that may radiate to the back, and is a medical emergency requiring immediate intervention.
  • Mesenteric Ischemia: A condition where the blood flow to the intestines is blocked, leading to severe abdominal pain out of proportion to the physical examination, and can rapidly progress to bowel infarction if not treated.
• Rare Diagnoses
  • Intussusception: A condition where a part of the intestine slides into an adjacent part, often causing severe abdominal pain, vomiting, and bloody stools. It's more common in children but can occur in adults.
  • Porphyria: A group of disorders that can cause severe abdominal pain, among other symptoms, due to the accumulation of porphyrins.
  • Lead Poisoning: Can cause abdominal pain, constipation, and neurological symptoms. It's rare but should be considered in individuals with exposure to lead.

Each of these diagnoses has distinct characteristics and risk factors that can help guide the diagnostic process. A thorough history, physical examination, and appropriate diagnostic tests are crucial for determining the cause of abdominal pain.