Cushing ulcer

**Definition:** A stress ulcer of the upper GI tract (classically the stomach, but also the duodenum or esophagus) associated with CNS injury: traumatic brain injury, intracranial hemorrhage, brain tumor, or neurosurgical procedures.

**Pathophysiology:** - Increased intracranial pressure (ICP) or direct brainstem/hypothalamic injury leads to vagal (parasympathetic) overstimulation. - Vagal stimulation increases ACh release, which acts on M3 receptors on parietal cells. It also increases gastrin and histamine release (ECL cells), causing gastric acid hypersecretion. - Net result: acid hypersecretion with mucosal injury. Often the ulcers are deeper and more likely to perforate than other stress ulcers. - Contrast with Curling ulcer (severe burns): mechanism is hypovolemia and mucosal hypoperfusion/ischemia with reduced mucosal defenses, not acid hypersecretion.

**Related: Cushing reflex (triad):** hypertension (widened pulse pressure), bradycardia, and irregular respirations, which indicate raised ICP. The Cushing ulcer is named for the same physician, Harvey Cushing, and is not related to Cushing syndrome.

**Clinical features:** - Often occurs within days of CNS insult in ICU patients. - Epigastric pain is often masked by altered mental status. Presentation is typically upper GI bleeding (hematemesis, melena, coffee-ground NG aspirate), or sudden perforation (peritonitis, free air under the diaphragm). - Can be multiple and deep (penetrating through the mucosa and muscularis).

**Diagnosis:** Upper endoscopy (EGD). An upright chest x-ray or abdominal CT shows free air if perforated.

**Management and prevention:** - Resuscitation, then PPI or H2 blocker. Endoscopic hemostasis for active bleeding, with surgery or IR for refractory bleeding or perforation. - Stress ulcer prophylaxis (PPI or H2 blocker) in high-risk ICU patients: mechanical ventilation >48 h, coagulopathy, TBI, or burns. - Early enteral feeding is protective. - Treat the underlying cause of increased ICP.

**High-yield comparisons:** - Cushing ulcer: CNS injury, increased ICP, vagal stimulation, increased acid, brain injury. - Curling ulcer: severe burns, hypovolemia/ischemia, decreased mucosal protection, with the stomach/duodenum affected. - Stress gastritis/ulcer: critical illness, sepsis, shock, and mechanical ventilation. - NSAID ulcer: decreased prostaglandins, so decreased mucus and bicarbonate. - H. pylori ulcer: urease-producing bacteria, with the duodenum more affected than the stomach.