A 61-year-old man presents to the emergency department with progressive nausea and vomiting over the past 6 weeks. He reports that he frequently vomits undigested food several hours after meals and has lost 15 pounds during this period. His medical history is significant for longstanding peptic ulcer disease for which he intermittently takes over-the-counter antacids. He has not undergone prior endoscopic evaluation in the past 3 years. Medications include calcium carbonate as needed. Temperature is 36.8°C (98.2°F), blood pressure is 106/68 mm Hg, pulse is 102/min, and respiratory rate is 14/min. Physical examination reveals mild epigastric distention and a succussion splash. Laboratory studies show the following:
Sodium: 133 mEq/L
Potassium: 2.9 mEq/L
Chloride: 89 mEq/L
Bicarbonate: 36 mEq/L
Which of the following is the most likely diagnosis?
The correct answer is:
B) Gastric outlet obstruction
This patient has several classic findings of gastric outlet obstruction (GOO): progressive postprandial vomiting, vomiting of undigested food hours after meals, weight loss, dehydration, and a succussion splash on examination. The laboratory findings of hypokalemic, hypochloremic metabolic alkalosis result from prolonged vomiting and loss of gastric hydrochloric acid. The history of longstanding peptic ulcer disease is particularly important because chronic inflammation and fibrosis of the pylorus or proximal duodenum can produce mechanical obstruction.
Although peptic ulcer disease was historically the most common cause of GOO, gastric and pancreatic malignancies are now increasingly important causes in adults and should be excluded with upper endoscopy. Patients often present with early satiety, nausea, vomiting, weight loss, and electrolyte abnormalities. Initial management includes fluid resuscitation, correction of electrolyte abnormalities, gastric decompression when necessary, and definitive evaluation of the underlying cause.
Answer choice A: Acute pancreatitis, is incorrect.
Acute pancreatitis typically presents with severe epigastric pain radiating to the back, nausea, and elevated pancreatic enzymes. It does not usually cause chronic vomiting of retained food or a succussion splash.
Answer choice C: Hepatic encephalopathy, is incorrect.
Hepatic encephalopathy causes neuropsychiatric abnormalities such as confusion, altered mental status, and asterixis. It does not produce gastric retention or metabolic alkalosis from vomiting.
Answer choice D: Small bowel obstruction, is incorrect.
Small bowel obstruction can cause vomiting and abdominal distention. However, delayed vomiting of undigested food, a succussion splash, and the history of peptic ulcer disease specifically suggest obstruction at the gastric outlet rather than distal bowel obstruction.
Answer choice E: Ulcerative colitis, is incorrect.
Ulcerative colitis causes chronic inflammatory diarrhea and hematochezia. It does not present with upper gastrointestinal obstructive symptoms.
Key Learning Point
Gastric outlet obstruction should be suspected in patients with postprandial vomiting of undigested food, weight loss, and hypochloremic metabolic alkalosis. Adults require evaluation for both peptic ulcer-related scarring and malignancy.
