A patient comes with hematemesis and melena. On the upper GI endoscopy, there were no significant findings. 2-days later the patient rebleeds. Next line of investigation is
**Core Concept**
The patient's symptoms of hematemesis and melena suggest upper gastrointestinal bleeding (UGIB), which requires accurate diagnosis and management. The initial negative upper GI endoscopy does not rule out the possibility of a non-bleeding visible vessel or a bleeding ulcer that is not actively bleeding at the time of endoscopy.
**Why the Correct Answer is Right**
In cases of UGIB with a negative initial endoscopy, the next step is to investigate for a non-bleeding visible vessel or a bleeding ulcer that may have been missed. This can be achieved through the use of **esophagogastroduodenoscopy (EGD) with or without the use of a vasoconstrictor (e.g., epinephrine) or a bleeding agent (e.g., indigo carmine)**, which can help identify the source of bleeding. Another option is **angiotensin-converting enzyme (ACE) inhibitor challenge**, which can help diagnose a bleeding duodenal ulcer.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the clinical scenario described, as the patient has already undergone an upper GI endoscopy.
**Option B:** This option is incorrect because it does not address the possibility of a non-bleeding visible vessel or a bleeding ulcer that may have been missed during the initial endoscopy.
**Option D:** This option is incorrect because it is not a specific or targeted approach to investigating the source of bleeding in this patient.
**Clinical Pearl / High-Yield Fact**
In cases of UGIB with a negative initial endoscopy, it is essential to consider the possibility of a non-bleeding visible vessel or a bleeding ulcer that may have been missed, and to use targeted investigations such as EGD with or without a vasoconstrictor or bleeding agent, or ACE inhibitor challenge to diagnose the source of bleeding.
**Correct Answer:** C.