Learning objectives

• Define multiple endocrine neoplasia syndromes
• Describe the differences between MEN type 1 and MEN type 2
• Anesthetic management of patients with multiple endocrine neoplasia syndromes

Definition and mechanisms 

• Multiple endocrine neoplasia (MEN) syndromes are characterized by hyperplasia of or a tumor in specific endocrine system glands and tissues
• Caused by a genetic mutation, autosomal dominant inheritance

Classification

MEN type 1

• Genetic condition in which multiple tumors affect different aspects of the endocrine system
• Most common affected areas: Parathyroid glands, gastroenteropancreatic tract, and anterior pituitary gland
• Less common types of tumors: Neuroendocrine tumors of the thymus and bronchi, adrenocortical tumors, lipomas, visceral leiomyomas, truncal and facial collagenomas, facial angiofibromas, breast cancer, meningioma, ependymomas
• Most tumors are benign
• Tumors are due to the inactivation of the MEN 1 oncosuppressor gene located on chromosome 11q13

MEN type 2

• Genetic polyglandular cancer syndrome
• All patients develop medullary thyroid carcinoma and have an increased risk of developing other tumors affecting other endocrine glands
• Patients with MEN type 2 also develop one or both of the following conditions
  • Pheochromocytoma
  • Hyperparathyroidism 
• Tumors result from oncogenic point mutations of the c-Ret proto-oncogene located on chromosome 10cen-10q11.2

Signs and symptoms

• Symptoms vary depending on which glands are affected by the hyperplasia or tumor
• Hyperplasia or tumors cause the affected glands to produce and release more hormones than normal
• Symptoms vary from person to person 

MEN type 1 

MEN type 2

Diagnosis

Treatment

Dependent on what endocrine glands and organs are affected, treatment may include

• Medications to treat symptoms and counteract the side effects of excess hormones
• Surgery to remove tumors or entire affected glands (e.g., thyroidectomy, parathyroidectomy)
• Replacement hormones if an endocrine gland is surgically removed
• Cancer treatment (e.g., chemotherapy and radiation) in case of metastasis

Management

Anesthetic challenges per tumor

• Parathyroid tumors: Hypercalcemia 
  • Maintain hydration and urinary output 
  • Main risk: Potential for cardiac dysrhythmias
  • Unpredictable responses to muscle relaxants 
  • Careful positioning due to the possible presence of osteoporosis and the potential for pathologic fractures
• Gastrinomas
  • Correct hypovolemia and electrolyte imbalance (hypokalemia and metabolic alkalosis)
  • Large gastric fluid volumes from gastric hypersecretion → vulnerable to aspiration during anesthetic induction
  • Gastroesophageal reflux is common → rapid sequence induction with maintenance of cricoid pressure
• Insulinomas: Hypoglycemia
  • Maintain normal blood glucose concentrations to prevent cerebral damage
    • Place an intra-arterial catheter to measure glucose levels regularly 
    • Administer IV glucose 
  • Anesthetic technique should focus on agents that decrease the cerebral metabolic rate for oxygen (avoid ketamine)
  • Maintain normocarbia during controlled ventilation
  • Patients might be obese → pay attention to the airway and address respiratory and cardiac issues
• Prolactinoma
  • No specific anesthetic considerations
• Medullary thyroid carcinoma
  • Enlarged thyroid causing airway compromise 
  • Intraoperative damage to the recurrent laryngeal nerve → may cause hoarseness, stridor, and complete airway obstruction upon extubation of the trachea or in the PACU
  • Airway may also become compromised by hematoma formation compressing the trachea
• Pheochromocytoma: Hypertension
  • Prevent hypertension and tachycardia → smooth anesthesia induction and endotracheal intubation
  • Avoid catecholamine release induced by anesthetic or surgical maneuvers 
  • Correct hypovolemia and electrolyte imbalances

See also hyperparathyroidism considerations

See also pheochromocytoma considerations

Keep in mind

• The anesthetic course may range from routine with no special requirements to severe and life-threatening depending on the tumor
• Some syndromes demand specific management techniques, but a carefully and thoughtfully administered anesthetic is the key to a successful outcome in patients with MEN

Suggested reading

• Multiple Endocrine Neoplasia (MEN). In: Bissonnette B, Luginbuehl I, Marciniak B, Dalens BJ. eds. Syndromes: Rapid Recognition and Perioperative Implications. McGraw Hill; 2006. Accessed March 07, 2023. https://accessanesthesiology.mhmedical.com/content.aspx?bookid=852&sectionid=49517985 
• Grant F. Anesthetic considerations in the multiple endocrine neoplasia syndromes. Curr Opin Anaesthesiol. 2005;18(3):345-352.