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| Zollinger-Ellison syndrome |
A triad of (Marked elevated gastric acid secretion, Peptic ulcer disease, A gastrinoma or non-beta islet cell tumor of the pancreas or duodenal wall which produces gastrin). Gastrinomas (at time of diagnosis) may be single or multiple (1/2-2/3), large or small, benign or malignant (2/3), sporadic (70-75%) or associated with multiple endocrine neoplasia (MEN 1)(25-30%)
SIGNS AND SYMPTOMS:
- Abdominal pain >80%
- Epigastric pain
- Reflux esophagitis
- Vomiting unresponsive to standard therapy
- Diarrhea including while fasting 40-70%
- Peptic ulcer disease
- Weight loss
- Hepatomegaly with metastasis
- Steatorrhea
- Endoscopic findings including esophagitis, duodenal ulceration with multiple ulcers and prominent gastric and duodenal folds
- Complications of severe peptic ulcer disease including hemorrhage, perforation and obstruction
- Signs of MEN 1 including those of hypercalcemia hyperparathyroidism and Cushing's syndrome.
CAUSES:
Gastrinoma equally distributed between the head of the pancreas and the first or second portion of the duodenum. May also be found rarely in the mesentery, peritoneum, spleen, skin or mediastinum (possibly metastasis with primary not identified).
LABORATORY:
- Elevated serum gastrin-fasting (>1000 pg/mL with ulcers diagnostic, >200 pg/mL with ulcers suggestive)
- Elevated basal gastric acid output >15 mEq/hr (>15 mmol/hr)
- Gastric pH <2.0>
- Check serum calcium, phosphorous, cortisol and prolactin (to R/O MEN 1)
APPROPRIATE HEALTH CARE:
- Advise daily care based on symptoms
- Appropriate surveillance of basal gastric acid output to monitor anti-acid secretory therapy
- Appropriate surveillance postoperatively to look for metastasis
GENERAL MEASURES:
- Advanced imaging initially to assess for possible resection
- Surgical removal when primary can be identified and as an adjunct for symptom control
- Medical treatment for symptom control when primary not found or metastasis present on diagnosis
SURGICAL MEASURES:
- Laparotomy to search for resectable tumors unless have liver metastasis on presentation or MEN 1
- Definitive therapy-removal of gastrinomas when found (surgery finds 95% of tumors, 5 year cure 30% when all can be removed)
- Total gastrectomy was formerly used to stop acid production before pharmacologic therapy available, now seldom done
- Vagotomy in some patients will reduce acid secretion and improve therapeutic effect of medication. May allow decrease dose of medication.
- In MEN 1 parathyroidectomy by lowering calcium may decrease acid production and decrease antisecretory drug use. Gastrinomas generally benign but multiple and not usually cured by surgery.
DIET:
Restrict foods which aggravate symptoms
Contraindications:
- Known hypersensitivity to the drug
- H2-blockers-androgen effects, drug interactions due to Cytochrome P-450 stimulation
- Omeprazole-none
- Lansoprazole-none
Precautions:
- Adjust doses for renal and geriatric patients depending on drug
- Gynecomastia reported with high dose cimetidine (>2.4 gm/d)
- Proton pump inhibitors may induce a profound and long lasting effect on gastric acid secretion, thereby affecting the bioavailability of drugs dependent on low gastric pH (eg, ketoconazole, ampicillin, iron)
ALTERNATIVE DRUGS:
- Octreotide appears helpful in slowing growth of liver metastasis. May produce regression in some cases.
- Chemotherapy regimens of streptozocin, 5-fluorouracil and doxorubicin show only limited response
- Interferon and shows more limited response; may be useful in combination with octreotide
Labels: Gastric acid secretion, Gastrinoma, Peptic ulcer disease |
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