Differential Diagnosis for Sudden Onset Upper Abdominal Pain

Single Most Likely Diagnosis

• Acute Pancreatitis: The sudden onset of upper abdominal pain, particularly with a tender mass slightly left of the midline, and vomiting, strongly suggests acute pancreatitis. The location of the pain and the presence of a mass are consistent with an inflamed pancreas.

Other Likely Diagnoses

• Peptic Ulcer Disease (PUD): Although the presence of a mass is less typical for PUD, a perforated ulcer could cause severe pain and vomiting. The location of the pain could be consistent with a duodenal ulcer.
• Gastroesophageal Reflux Disease (GERD) with Esophagitis: While less likely to cause a palpable mass, severe esophagitis could lead to significant pain and vomiting.
• Intestinal Obstruction: An obstruction, especially if it involves the proximal small bowel, could cause vomiting and abdominal pain. However, the presence of a tender mass is not as typical.

Do Not Miss Diagnoses

• Aortic Dissection: Although less common, an aortic dissection can present with sudden, severe abdominal pain and could potentially cause a palpable mass if there is an associated hematoma. This condition is life-threatening and requires immediate diagnosis and treatment.
• Ectopic Pregnancy: In a female patient, an ectopic pregnancy could present with abdominal pain and vomiting, but the presence of a mass and the specific location of the pain might be less typical. However, given the potential for severe consequences, it's crucial to consider in any female of childbearing age.
• Mesenteric Ischemia: This condition can cause severe abdominal pain out of proportion to the physical examination findings. It is a medical emergency and requires prompt diagnosis and treatment.

Rare Diagnoses

• Splenic Artery Aneurysm Rupture: This would be an unusual cause of abdominal pain and a palpable mass but could be considered in the differential, especially if there are risk factors such as pregnancy or liver disease.
• Hepatic Artery Aneurysm Rupture: Similar to a splenic artery aneurysm, this is rare but could present with abdominal pain and potentially a palpable mass if there is significant bleeding.
• Gastric Volvulus: This condition involves the stomach twisting abnormally and can cause severe pain and vomiting. It might not typically cause a palpable mass but could be considered in the differential diagnosis for severe upper abdominal pain.