A 67-year-old male presents with weakness, dizziness, and melena that began approximately 2 days ago. He denies trauma. His blood pressure is 90/50 mm Hg and his pulse is 120 beats/min and thready. You should be MOST suspicious that this patient is experiencing:

• A. gastrointestinal bleeding.
• B. intrathoracic hemorrhaging.
• C. an aortic aneurysm.
• D. acute appendicitis.

Answer: (A)

The main idea here is recognizing hemorrhagic shock from a gastrointestinal bleed. Melena means there is digested blood in the stool, pointing to an upper GI source such as a peptic ulcer or varices. The blood loss is causing the patient’s low blood pressure and rapid, weak pulse, which explains the dizziness and weakness. In this scenario, the GI bleed is the most likely cause of his signs and symptoms.

Other conditions don’t fit as well because they wouldn’t explain the black tarry stools. Intrathoracic hemorrhage would produce chest symptoms; a ruptured aortic aneurysm typically presents with sudden severe chest or back pain and shock but not melena; acute appendicitis presents with localized abdominal pain, tenderness, and possible fever, not GI bleeding with melena.