Differential Diagnosis for Acute Abdominal Pain

In the context of acute mesenteric ischemia, the differential diagnosis can be organized into the following categories:

• Single most likely diagnosis:
  • Acute Mesenteric Ischemia: This condition occurs when there is a sudden onset of insufficient blood flow to the intestines, which can lead to tissue death. It is a medical emergency and can present with severe abdominal pain, nausea, vomiting, and sometimes bloody stools. The clinical presentation, combined with risk factors such as atrial fibrillation, recent surgery, or hypercoagulable states, makes it a prime consideration.
• Other Likely diagnoses:
  • Acute Appendicitis: Inflammation of the appendix can cause severe abdominal pain, often starting near the navel and then moving to the lower right abdomen. While the pain pattern and location can differ from mesenteric ischemia, the severity and potential for complications (e.g., perforation) warrant its consideration.
  • Intestinal Obstruction: This condition involves a blockage that prevents normal flow of the products of digestion, including food, fluid, and gas. Symptoms can include severe abdominal pain, vomiting, bloating, and constipation. The mechanism of obstruction (e.g., adhesions, hernias, tumors) and the presence of fever or signs of peritonitis can help differentiate it from mesenteric ischemia.
  • Diverticulitis: Inflammation of the diverticula in the digestive tract can cause severe abdominal pain, usually on the lower left side, fever, nausea, and changes in bowel habits. While its presentation can overlap with mesenteric ischemia, the location of pain and presence of fever are clues to its diagnosis.
• Do Not Miss diagnoses:
  • Ruptured Aortic Aneurysm: A sudden, severe pain in the abdomen, back, or flank, potentially radiating to the groin, accompanied by signs of shock, makes this a critical diagnosis not to miss. The catastrophic nature of a ruptured aneurysm demands immediate recognition and intervention.
  • Ectopic Pregnancy: In women of childbearing age, severe lower abdominal pain, especially if accompanied by vaginal bleeding, dizziness, or fainting, should prompt consideration of an ectopic pregnancy. This condition is life-threatening and requires urgent diagnosis and treatment.
  • Perforated Peptic Ulcer: Sudden onset of severe abdominal pain, often described as "stabbing," that worsens over time, can indicate a perforated peptic ulcer. Free air under the diaphragm on an upright chest X-ray is diagnostic. The potential for peritonitis and sepsis makes prompt recognition crucial.
• Rare diagnoses:
  • Inferior Mesenteric Artery Aneurysm: Although rare, aneurysms of the inferior mesenteric artery can cause abdominal pain and potentially rupture, leading to severe consequences. Their rarity makes them less likely but still important to consider in the differential diagnosis of acute abdominal pain.
  • Primary Mesenteric Venous Thrombosis: This condition involves a blood clot in the veins that drain blood from the intestines and can cause severe abdominal pain, among other symptoms. It is less common than arterial ischemia but should be considered, especially in patients with hypercoagulable conditions or recent abdominal surgery.