After total thyroidectomy for multiple endocrine neoplasia type 2 (MEN 2), what additional complications and surveillance should be performed?

Post-Thyroidectomy Management in MEN2

After total thyroidectomy for MEN2, you must maintain lifelong surveillance for pheochromocytoma and hyperparathyroidism (in MEN2A), manage surgical complications (hypoparathyroidism and recurrent laryngeal nerve injury), provide appropriate levothyroxine replacement without TSH suppression, and monitor for medullary thyroid carcinoma recurrence using calcitonin levels.

Ongoing Surveillance for Other MEN2 Manifestations

Pheochromocytoma Screening

• Continue annual biochemical screening for pheochromocytoma indefinitely, as these tumors can develop at any time after thyroidectomy in both MEN2A and MEN2B 1
• Screen using plasma or 24-hour urine metanephrines and catecholamines 1
• If pheochromocytoma develops post-thyroidectomy, it must be removed before any additional neck surgery to prevent hypertensive crisis 1

Hyperparathyroidism Monitoring (MEN2A Only)

• Monitor for primary hyperparathyroidism in MEN2A patients, as this can occur or recur after thyroidectomy 2
• Annual serum calcium and PTH measurements are indicated 2
• MEN2B and familial MTC patients do not typically develop hyperparathyroidism 2

Surgical Complications Management

Hypoparathyroidism

• Hypoparathyroidism is the most common significant complication after total thyroidectomy, occurring with higher frequency than after partial procedures 1
• Monitor calcium levels closely in the immediate postoperative period and long-term 1
• Cryopreserved parathyroid tissue should have been stored during surgery to allow future autotransplantation if permanent hypoparathyroidism develops 1

Recurrent Laryngeal Nerve Injury

• The second most common significant complication is recurrent laryngeal nerve injury 1
• Assess vocal cord function if hoarseness or voice changes develop 1

Levothyroxine Management

Maintain TSH in the normal range—do NOT suppress TSH, as medullary thyroid carcinoma cells lack TSH receptors, making suppression both ineffective and potentially harmful 1

• Adjust levothyroxine dose to keep TSH within normal laboratory reference range 1
• This differs fundamentally from papillary or follicular thyroid cancer management 1

Medullary Thyroid Carcinoma Surveillance

Calcitonin Monitoring Strategy

• If basal calcitonin remains undetectable after provocative testing, no additional surgery is needed, with only a 3% recurrence risk during long-term follow-up 3
• For detectable postoperative calcitonin <150 pg/ml, perform careful neck ultrasound to evaluate for locoregional disease 3
• For calcitonin ≥150 pg/ml, obtain imaging for distant metastases before considering additional neck surgery 3

Prognosis Considerations

• Biochemical cure is unlikely if lymph nodes were positive initially—only 20% of such patients achieve undetectable calcitonin postoperatively 3
• MEN2B patients have more aggressive disease than MEN2A, with higher rates of persistent disease despite childhood thyroidectomy 1
• Patients with exon 16 mutations (codon 918, typical of MEN2B) have particularly aggressive disease 1

Additional Imaging Surveillance

• Neck ultrasound should be performed to evaluate for thyroid remnants, nodal abnormalities, or recurrent disease 3, 4
• CEA levels can be monitored alongside calcitonin—a rapidly increasing CEA with stable calcitonin suggests worse prognosis 1

Critical Pitfalls to Avoid

• Never screen for recurrence using radioiodine imaging—medullary thyroid carcinoma cells do not concentrate radioactive iodine 1
• Do not suppress TSH with excessive levothyroxine doses, as this provides no benefit and causes harm 1
• Do not assume the patient is cured based on surgery alone—continued biochemical and clinical surveillance is mandatory 3
• Remember that familial MTC patients may later manifest other MEN2A features, requiring continued surveillance for pheochromocytoma and hyperparathyroidism 2