## **Core Concept**
Cushing ulcers, also known as Cushing's ulcers or stress ulcers, are a type of acute peptic ulcer that occurs in the setting of severe head injuries, intracranial hemorrhage, or other causes of increased intracranial pressure. These ulcers are a form of stress ulcer and can lead to significant morbidity and mortality.

## **Why the Correct Answer is Right**
The correct answer, **C. Head injury**, is right because Cushing ulcers are specifically associated with increased intracranial pressure (ICP), which can result from head injuries, intracranial hemorrhages, or other conditions that elevate ICP. The mechanism involves the hypothalamic-pituitary-adrenal axis activation, leading to increased cortisol levels, which impair the mucosal defense mechanisms of the stomach and duodenum, making them susceptible to ulceration.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Myocardial infarction - While stress ulcers can occur in the setting of severe myocardial infarction due to the systemic stress response, Cushing ulcers are more specifically associated with increased intracranial pressure rather than cardiac conditions.
- **Option B:** Burns - Burns can lead to stress ulcers due to the systemic stress response and potential for hypovolemia and ischemia to the gastric mucosa. However, they are not the primary condition associated with Cushing ulcers.
- **Option D:** Severe infection - Severe infections can also lead to stress ulcers through systemic inflammation and the stress response. However, like burns and myocardial infarction, severe infection is not the specific condition associated with Cushing ulcers.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that Cushing ulcers are often associated with **increased intracranial pressure** and can be a complication in patients with severe head injuries. These ulcers can be particularly dangerous because they may not present with typical symptoms due to the altered mental status of the patient, leading to delayed diagnosis.

## **Correct Answer: C. Head injury**