USMLE Q Bank Step 1- 205

A 50 year-old man presents to the clinic with a long history of heartburn after eating, exaggerated when he is lying down and lessened when he takes antacids. Endoscopy reveals a large irregular, erythematous area in the lower esophagus.  Esophageal motility studies reveal dysfunction of the lower esophageal sphincter (LES).

Which of the following most likely leads to increase in the resting pressure of LES?







All of the choices except protein lead of relaxation of the lower esophageal sphincter. Dietary protein, histamine and antacids cause increased resting pressure of the lower esophageal sphincter and eventually improve the symptoms of GERD. On the other hand, dietary fat, alcohol, chocolate, caffeine and smoking lead to relaxation of the LES causing exaggeration of these symptoms.

The correct answer is E

5 thoughts on “USMLE Q Bank Step 1- 205”

  1. Which histamine receptor increase LESpressure (1or ll)

  2. Early studies showed that protein increased LES tone while fat decreased it. Etiology is unknown. Thank you for your question.

  3. sir what is the physiology behind protein increasing LES tone

  4. Hello Dr. It is one of the main remedies to GERD is to eat high protein diet and low fat as protein is increasing LES resting pressure leading to improvement of symptoms in contrast to fat which decreases LES resting pressure leading to exaggerated reflux.

  5. Hello sir i have doubt in the above question.Usually fat only causes increase in LES resting pressure ?please do clear my doubt. Thank you so much for posting such questions.

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