Rosh Emergency Medicine Practice Test

What is the most appropriate initial diagnostic study for a patient presenting with severe sudden-onset abdominal pain and rigid abdomen?

1. Abdominal ultrasound

2. CT scan of abdomen and pelvis

3. Upper endoscopy

4. Upright chest radiograph

The correct answer is: Upright chest radiograph

In the context of severe sudden-onset abdominal pain accompanied by rigidity, the most appropriate initial diagnostic study is an upright chest radiograph. This imaging modality is effective for detecting free air under the diaphragm, which can indicate the presence of a perforated visceral organ, such as in cases of perforated peptic ulcer or bowel perforation. The rigid abdomen suggests underlying intra-abdominal pathology, and the upright position of the patient maximizes the chance of visualizing any free air, which is a critical finding in acute abdominal emergencies. Although abdominal ultrasound and CT scans are useful in evaluating abdominal pain, they may not be the best initial study in this scenario where immediate identification of potentially life-threatening conditions is crucial. Upper endoscopy is not indicated for acute abdominal pain and would not provide any pertinent information in this scenario, especially since it is more suited for evaluating upper gastrointestinal tract issues rather than diagnosing causes of acute abdominal pain. Therefore, an upright chest radiograph serves as a quick, efficient first step in assessing the patient for serious conditions that require urgent intervention.