Further Inpatient Care

After parathyroid surgery, monitor serum ionized calcium and magnesium levels. Transient hypoparathyroidism frequently develops and requires calcium and vitamin D supplementation. In rare cases, hungry-bone syndrome may ensue, with rapid declines in serum calcium and magnesium levels.

• Somatostatin therapy is indicated particularly in patients with acromegaly in whom surgery did not achieve complete tumor removal. Tumor shrinkage can be expected in one third of patients, normalization of IGF-1 levels can be expected in as many as two thirds.

• Pregnancy may ensue with treatment that includes cabergoline or bromocriptine in patients with prolactinoma.

Further Outpatient Care

• In MTC, measure serum calcitonin levels every 6-12 months after surgery. Elevated serum levels in the neck region indicate recurrence that possibly requires further surgery. However, micrometastases often cannot be visualized by using current imaging techniques.

• The resection of one endocrine tumor does not exclude a second tumor, even after an interval of several years. Patients need lifelong surveillance, as do their offspring.

• Pheochromocytomas are monitored with blood pressure and plasma free metanephrines as well as 24-hour urinary catecholamines, including fractionated metanephrine measurements, to exclude recurrence.

Inpatient & Outpatient Medications

• Patients with type 1 multiple endocrine neoplasia (MEN) and ZES need lifelong acid inhibition with PPIs.

• Chemotherapy with streptozocin and dacarbazine may reduce the size of nonoperable neuroendocrine tumors.

Deterrence/Prevention

• Because early therapy substantially improves the patient’s prognosis, screening is of paramount importance in all forms of multiple endocrine neoplasia (MEN).

• Risk factors include known MEN, a positive family history of MEN, ZES, ganglioneuromas, cutaneous neuromas, a marfanoid somatic phenotype, parathyroid hyperplasia, multicentric medullary carcinoma of the thyroid, and multicentric or bilateral pheochromocytomas.

• Screening tests include the following measurements based on the type of MEN: o Type 1 multiple endocrine neoplasia – Serum calcium and intact PTH, prolactin, plasma chromogranin A, fasting gastrin, fasting glucose and insulin, and free IGF-I determinations

• Type 2A multiple endocrine neoplasia -RET germline mutation testing and determinations of plasma calcitonin, plasma free metanephrines and 24-hour urinary catecholamines (including fractionated metanephrines), and serum calcium levels

• Type 2B multiple endocrine neoplasia -RET germline mutation testing and determinations of serum calcitonin, plasma free metanephrines, and 24-hour urinary catecholamines including fractionated metanephrines

• If test results are in the reference range on 3 occasions and if the patient is older than 35 years, he or she can be declared a noncarrier. Offspring of noncarriers do not require testing. Mutation analysis of the MENIN gene enables the identification of people carrying a germline mutation.

Prognosis

• Type 1 multiple endocrine neoplasia
  • The prognosis is generally good in the presence of discrete parathyroid and pancreatic islet disease or pituitary adenoma.
  • Pancreatic islet cell carcinoma and carcinoids are slowly progressive.
  • Patients with gastrinoma in type 1 MEN may have a prognosis better than that of patients with the sporadic form of the disease.

• Type 2A multiple endocrine neoplasia: The prognosis depends on the stage of medullary thyroid cancer and is generally good after prophylactic thyroidectomy.

• Type 2B multiple endocrine Neoplasia
  • The prognosis for patients with type 2B MEN is worse than for patients with type 2A MEN because tumors, such as MTCs, are relatively aggressive, resulting in a 10-year survival rate of 50%.
  • Therefore, individuals with an RET germline mutation in exon 16 should undergo early prophylactic thyroidectomy and screening for pheochromocytomas.

Reprinted with permission from eMedicine.com, 2008. Available at: http://emedicine.medscape.com/article/923269-followup