A 45-year-old man comes to the office with a 6-month history of recurrent, burning epigastric pain and diarrhea. His stools are frothy and unusually foul smelling and they float. The patient's clothes fit loosely, and he believes that he may have lost some weight. He has tried several over-the-counter medications, including antacids, H-2 blockers, and proton pump inhibitors, with moderate success. Vital signs are normal. Examination shows no abnormalities except for midepigastric tenderness to deep palpation. Test of the stool for occult blood is positive, and stool fat is also positive. Gastrointestinal endoscopy reveals two duodenal ulcers and a jejunal ulcer. Which of the following is the best explanation for this patient's impaired fat absorption?
Zollinger-Ellison syndrome | |
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Clinical features |
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Workup |
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MEN1 = multiple endocrine neoplasia type 1. | |
This patient with multiple peptic ulcers and diarrhea has clinical features of Zollinger-Ellison syndrome (ZES). ZES is due to a gastrin-producing tumor, which usually occurs in the pancreas or duodenum. Most cases are sporadic, but ZES also occurs frequently in the context of multiple endocrine neoplasia type 1 (MEN1). Uncontrolled gastrin secretion leads to parietal cell hyperplasia, with excessive production of gastric acid. Multiple duodenal (and sometimes jejunal) ulcers are typical, and the ulcers can be refractory to standard acid-reducing medications. The excess gastric acid in the small intestine can cause diarrhea and steatorrhea due to inactivation of pancreatic enzymes and injury to the mucosal brush border.
The diagnosis of ZES is suggested by a markedly elevated serum gastrin level (>1000 pg/mL) in the presence of acidic gastric pH (<4). Endoscopy usually reveals ulcers (>90% of patients with ZES) and occasionally will identify a primary duodenal gastrinoma. CT, MRI, and somatostatin receptor scintigraphy can be used to identify pancreatic tumors and metastatic disease. If gastrinoma is confirmed, patients should be screened for MEN1 with assays for parathyroid hormone, ionized calcium, and prolactin.
(Choices A, B, and C) Celiac disease is an autoimmune disorder characterized by malabsorption due to mucosal villous atrophy triggered by exposure to gluten-containing wheat products. Small intestinal bacterial overgrowth can also cause mucosal injury, possibly due to bacterial toxins. Pancreatic exocrine deficiency can be seen in chronic (eg, alcoholic) pancreatitis, cystic fibrosis, and pancreatic resection. However, duodenal and jejunal ulcerations are not typical in these conditions.
(Choice E) Bile acids are primarily reabsorbed in the ileum; impaired absorption can cause malabsorption of fats. This is typically seen following extensive ileal resection in Crohn disease (CD), which presents with chronic or recurrent abdominal pain, fever, diarrhea, and weight loss. It would be unusual for CD to present with multiple duodenal ulcers.
Educational objective:
Zollinger-Ellison syndrome should be suspected in patients with multiple duodenal ulcers refractory to treatment or ulcers distal to the duodenum or associated with chronic diarrhea. In these patients, inactivation of pancreatic enzymes by increased production of stomach acid may lead to malabsorption.