A 43-year-old male presented to the Emergency Department complaining for vomiting and dyspepsia. He refused persistently to give any more details. He asked for an intramuscular injection of metoclopramide, refusing further investigation, since "he already knew his problem ("recurrent gastritis")". However, he was convinced to undergo an electrocardiogram in our attempt to rule out vomiting of cardiac origin, which showed ST changes and minimal U wave, suggestive of hypokalemia (Figure 1). The physical examination on presentation was unremarkable except for epigastric tenderness. Routine laboratory testing on admission was unremarkable except for low serum potassium (K=2,1 mmol/liter). The arterial blood gas testing showed metabolic alkalosis (pH=7,66, bicarbonate = 55,2 mmol/liter, pC02 49mmHg, pO2 63mmHg, saturation O2 96%). Since his symptoms insisted, the patient accepted to be admitted.

During his hospitalization, he revealed that he had history of upper gastrointestinal bleeding four years earlier without undergoing further investigation. Since then he has been complaining for occasional vomiting that was empirically managed with metoclopramide. He didn't report chest pain, headache, fever, weight loss, or other symptoms. He was afraid of hospitals and doctors and he avoided visiting his family physician. The last two weeks prior to admission, his condition deteriorated. His other past medical history was unremarkable and he received no medications, except the occasional use of metoclopramide. He did not smoke and he did not drink alcohol.
Question
Based on the patient's history and physical examination, which one of the following is the most likely diagnosis?
A. Functional or non-ulcer dyspepsia
B. Peptic ulcer disease complicated by pyloric stenosis
C. Esophagitis or reflux without esophagitis
D. Gastric or esophageal cancer
E. Biliary track disease

Click here for the diagnosis