Differential Diagnosis for Hematemesis

The patient presents with several episodes of hematemesis, which is the vomiting of blood, indicating upper gastrointestinal bleeding. Given the patient's history and lab results, we can categorize the differential diagnoses as follows:

• Single Most Likely Diagnosis

  • A. Peptic Ulcer Disease: This is the most common cause of upper GI bleeding and can present with hematemesis. The high BUN level may indicate dehydration, which can be a consequence of significant blood loss. The absence of liver disease stigmata and normal ALT makes other liver-related causes less likely.

• Other Likely Diagnoses

  • D. Erosive Gastritis: Although less common than peptic ulcer disease, erosive gastritis can cause significant upper GI bleeding. The patient's lack of medication use (e.g., NSAIDs) makes this less likely, but it remains a consideration.
  • B. Mallory-Weiss Syndrome: This condition involves tears in the mucous membrane or lining of the lower end of the esophagus, where it connects to the stomach. These tears can bleed. The syndrome is often associated with intense or prolonged vomiting, retching, or coughing but can occur without a clear history of such.

• Do Not Miss Diagnoses

  • C. Esophageal Varices: Although the patient does not have stigmata of liver disease and normal ALT, esophageal varices due to portal hypertension (which could be from non-cirrhotic causes) can cause life-threatening bleeding. Missing this diagnosis could be fatal, so it's crucial to consider it, even if it seems less likely based on the provided information.
  • Consideration should also be given to other vascular anomalies or rare causes of bleeding that could be life-threatening if not promptly diagnosed and treated.

• Rare Diagnoses

  • Gastrointestinal tumors or vascular malformations: These are less common causes of upper GI bleeding but should be considered, especially if common causes are ruled out.
  • Ingestion of caustic substances: Although the patient is not on any medication, accidental or intentional ingestion of caustic substances could lead to hematemesis.
  • Inflammatory or infectious causes: Conditions like Crohn's disease or infectious gastritis could potentially cause upper GI bleeding, though they would be less common presentations for these conditions.

Each of these diagnoses should be considered in the context of the patient's full clinical picture, including further history, physical examination, and diagnostic testing as needed. Endoscopy is often crucial for directly visualizing the source of bleeding in the upper GI tract.