Esophagus and Stomach
Core concepts
Master the motility and mucosal disorders first. For achalasia, know the manometric pattern (absent peristalsis with failure of LES relaxation) and that pseudoachalasia from malignancy must be excluded, especially in older patients with rapid weight loss. Distinguish diffuse esophageal spasm (premature contractions with normal relaxation) from nutcracker/hypercontractile esophagus. Gastroesophageal reflux disease hinges on the mechanical barrier: transient LES relaxations, hiatal hernia, and impaired clearance. Barrett esophagus requires intestinal metaplasia with goblet cells and dysplasia grading drives surveillance intervals.
For the stomach, separate peptic ulcer disease by location and acid physiology: duodenal ulcers are associated with high acid, gastric ulcers with impaired mucosal defense, and every gastric ulcer needs biopsy to exclude malignancy. Know Helicobacter pylori testing pitfalls: serology stays positive after eradication, so use urea breath test or stool antigen for confirmation off PPI for adequate time. Gastroparesis is a diagnosis of delayed emptying without obstruction.
Traps
Questions conflate achalasia with scleroderma esophagus (which shows low-amplitude contractions and a patulous LES). They also test postprandial pain versus nocturnal pain, and Zollinger-Ellison when ulcers are multiple, distal, or refractory. Do not forget that NSAIDs are a leading ulcer cause independent of H pylori.
Rule of thumb
A gastric ulcer that fails to heal after 8-12 weeks of acid suppression mandates repeat endoscopy with biopsy regardless of initial benign histology.