Differential Diagnosis of Abdominal Pain
The differential diagnosis for abdominal pain is extensive and can be categorized based on the likelihood and potential impact of missing a diagnosis. Here's a structured approach:
- 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 lies in its high prevalence and the broad range of pathogens that can cause it, including viral, bacterial, and parasitic agents.
- 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 a common condition that can present with a variety of symptoms, making it a likely consideration.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic abdominal pain, diarrhea, weight loss, and sometimes blood in the stool. The chronic nature of these diseases and their impact on quality of life make them important to consider.
- Peptic Ulcer Disease: Gastric and duodenal ulcers can cause epigastric pain that may radiate to the back, worsen with food intake, and improve with antacids or food. The presence of Helicobacter pylori infection or the use of NSAIDs are common risk factors.
- 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. Classic symptoms include initial diffuse or epigastric pain that localizes to the right lower quadrant, fever, and leukocytosis.
- Ectopic Pregnancy: A life-threatening condition in women of childbearing age, presenting with abdominal pain, missed periods, and sometimes vaginal bleeding. A pregnancy test is crucial in the diagnostic workup.
- Mesenteric Ischemia: This condition involves insufficient blood flow to the intestines and can present with severe, diffuse abdominal pain out of proportion to physical examination findings, especially in older patients or those with cardiovascular risk factors.
- Pancreatitis: Inflammation of the pancreas can cause severe, persistent abdominal pain radiating to the back, nausea, vomiting, and elevated pancreatic enzymes. Gallstones and alcohol abuse are common causes.
- Rare Diagnoses
- Intussusception: A condition where a part of the intestine telescopes into another, causing bowel obstruction and potentially ischemia. It's more common in children but can occur in adults, often with a lead point like a tumor.
- Abdominal Aortic Aneurysm (AAA): A dilatation of the abdominal aorta that can cause abdominal pain, back pain, and a palpable abdominal mass. Rupture of an AAA is a medical emergency with high mortality.
- Porphyrias: A group of rare genetic disorders that can cause acute intermittent porphyria, leading to severe abdominal pain, neurological symptoms, and sometimes psychiatric disturbances.
Each of these diagnoses has distinct features and risk factors that guide the diagnostic process. A thorough history, physical examination, and judicious use of diagnostic tests are essential for accurately diagnosing the cause of abdominal pain.