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Complications of Thyroid Surgery
Case Synopsis 1
A 55-year-old woman with a 5-year history of swelling in the front of the neck presented for subtotal thyroidectomy. She has a history of palpitations on minimal exertion. She gives a history of shortness of breath on lying supine and prefers to sleep on her side. She also has an altered voice. A prominent thyroid gland is palpated on physical examination. The chest radiograph demonstrates moderate displacement of the trachea to the right from the midline. Indirect laryngoscopy revealed bilateral normal vocal cord function.
Case Synopsis 2
The same patient underwent uneventful subtotal thyroidectomy for multinodular goiter. The patient complains of difficulty in breathing 3 hours after surgery. On examination the patient is slightly restless, and mild inspiratory stridor is noted. Pulse oximetry reveals an arterial oxygen saturation of 94% on 2 L/min of nasal O 2 and other vital signs are stable.
Acknowledgment
The authors wish to thank Dr. Samuel A. Irefin for his contribution to the previous edition of this chapter.
Problem Analysis: Case Synopsis 1
Thyroid surgery may range from lobectomy to total thyroidectomy ( Table 51.1 ). Solitary thyroid nodule may be removed by lobectomy or hemithyroidectomy. The most common cause of hyperthyroidism is Graves disease. Toxic adenoma and toxic multinodular goiter (MNG) are other causes of hyperthyroidism. Surgical management of Graves disease involves near-total thyroidectomy. However, aggressive thyroid malignancy may require extensive neck dissection in addition to total thyroidectomy.
TABLE 51.1
Types of Thyroid Surgery
| Thyroid Disease | Type of Surgery | Potential for Complication |
|---|---|---|
| Small solitary nodule | Hemithyroidectomy | Low risk of injury to laryngeal nerves |
| Solitary toxic adenoma | Ipsilateral lobectomy | Hyperthyroidism |
| Retrosternal goiter | Subtotal thyroidectomy | Risk of severe bleeding, airway obstruction May require a sternotomy approach |
| Graves disease | Total thyroidectomy | Hyperthyroid crisis |
| Aggressive malignancy | Total thyroidectomy with neck dissection | Injury to the laryngeal nerves May require tracheostomy |
| Thyroglossal duct cyst excision | Sistrunk procedure | Inadvertent damage to thyroid cartilage causing severe airway obstruction |
Preoperative Assessment
Adequate preoperative assessment with optimal preparation of the patient minimizes the postoperative complications of thyroidectomy. Preoperative assessment involves history, examination, thyroid function tests, imaging, and evaluation of vocal cord function ( Table 51.2 ). Preoperatively it is important to ensure euthyroid status. Graves disease is a common cause of hyperthyroidism, followed by MNG and toxic adenomas.
TABLE 51.2
Preoperative Assessment
| History | To assess airway compromise (dyspnea on lying supine) To assess symptoms of hyperthyroidism/hypothyroidism Medication history including antiplatelet agents/anticoagulants Remember: association of pheochromocytoma with medullary carcinoma of thyroid |
| Examination | For retrosternal extension of goiter Look for SVC obstruction—facial plethora—Pemberton sign |
| Blood tests | Full blood count (methimazole may cause agranulocytosis) Blood grouping and typing Thyroid function tests |
| Imaging | Chest x-ray—tracheal deviation CT scan—anatomic level and extent of tracheal narrowing |
| Nasendoscopy | Assessment of vocal cord function |
| ECG (e.g., in AF) | Assess rhythm, presence of LVH, ischemic changes |
| Lung function tests Flow-volume loop |
In extrathoracic airway obstruction (goiter) the inspiratory airflow is reduced This distinguishes local pressure effects caused by the goiter from underlying asthma |
AF, Atrial fibrillation; CT, computed tomography; ECG, electrocardiogram; LVH, left ventricular hypertrophy; SVC, superior vena cava.
Elevated calcitonin levels may suggest medullary carcinoma of thyroid. Medullary carcinoma of thyroid gland is rare and may be associated with multiple endocrine neoplasia type 2 (MEN 2). The presence of pheochromocytoma should be excluded in all patients with MEN 2A or MEN 2B syndrome.
Recognition and Preparation of the Hyperthyroid Patient
Hyperthyroid patients may present with sudden weight loss, palpitations, fine tremors, and an enlarged thyroid gland. Correct diagnosis of the etiology of hyperthyroidism must be made before therapy is commenced. Hyperthyroid patients are at risk of developing thyroid storm perioperatively, so adequate preoperative treatment of hyperthyroidism is important. In the surgical management of hyperthyroidism, methimazole is the initial antithyroid agent used except in pregnant patients where propylthiouracil is preferred. In addition, β-blockers may be used, to control symptoms until euthyroid status is achieved. Inorganic iodine may be given for up to 10 days before surgery to decrease the vascularity of the thyroid gland in patients with Graves disease. Patients should have their thyroid function assessed at 4-week intervals. Neutrophil count should be monitored, as methimazole can cause agranulocytosis. Methimazole can be discontinued on the day of surgery.
Risk Assessment
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