Thyroid & Parathyroid Surgery Complications
Airway, voice, and calcium: what goes wrong in the central neck
Neck hematoma: an airway emergency
Mechanism. Bleeding usually declares itself in the first 6–24 hours. Blood trapped beneath the closed strap muscles compresses the veins and lymphatics draining the larynx, so laryngeal edema, more than tracheal compression, narrows the airway. Warning signs are rapid neck swelling, pain, dysphagia, and anxiety, then stridor and hypoxia.
- Call for help and open the woundAt the bedside, cut the skin sutures and reopen the strap-muscle closure
- Evacuate the clotDecompression often improves breathing at once
- Secure the airwayIntubate if distress persists; delay worsens edema
- Return to the ORFind and control the bleeding vessel, irrigate, and close
Do not send a patient with a post-thyroidectomy hematoma and stridor for CT or attempt intubation before decompressing the neck. A stable, nonexpanding hematoma without airway symptoms can be evacuated in the OR.
Laryngeal nerve injuries
Anatomy. The recurrent laryngeal nerve (RLN) supplies every intrinsic laryngeal muscle except the cricothyroid, including the posterior cricoarytenoid, the only abductor. It ascends in the tracheoesophageal groove and is most vulnerable near the inferior thyroid artery and the ligament of Berry. The right RLN loops under the subclavian artery, the left under the aortic arch; a nonrecurrent right nerve accompanies an aberrant right subclavian artery.
| Injury | Findings | Management |
|---|---|---|
| Unilateral RLN | One cord paralyzed near the midline: hoarse, breathy voice, weak cough, aspiration of thin liquids; airway usually adequate | Laryngoscopy; swallowing precautions and voice therapy; injection medialization or thyroplasty if persistent |
| Bilateral RLN | Both cords near the midline: stridor and distress right after extubation, voice may be nearly normal | Reintubate; tracheostomy if function does not recover |
| External branch, superior laryngeal nerve | Cricothyroid weakness: lost high pitch, voice fatigue, weak projection | Voice therapy; prevent by ligating superior pole vessels close to the gland |
| Internal branch, superior laryngeal nerve | Supraglottic numbness, blunted cough reflex, aspiration | Swallowing therapy |
Course and prevention. Most RLN injuries are neurapraxias that recover within 6–12 months. Laryngoscopy documents cord function before surgery and confirms new paralysis afterward. If nerve monitoring loses signal on the first side, staging the contralateral lobe avoids bilateral paralysis.
Hypocalcemia after neck surgery
Cause and timing. Hypocalcemia is the most common complication of total thyroidectomy, transient in up to about a third of patients and permanent (beyond 6–12 months) in roughly 1–3%. It follows removal or devascularization of the parathyroids, supplied mainly by the inferior thyroid artery, and typically appears 24–72 hours after surgery. A devascularized gland is minced and autotransplanted into the sternocleidomastoid. A low PTH hours after surgery or the next morning predicts hypocalcemia and justifies prophylactic calcium with calcitriol.
Recognition. Perioral and fingertip tingling and muscle cramps come first, followed by carpopedal spasm, tetany, laryngospasm, and seizures. Chvostek sign is facial twitching when the facial nerve is tapped in front of the ear; Trousseau sign, carpal spasm after a blood pressure cuff is held above systolic pressure for 3 minutes, is more specific. The ECG shows a prolonged QT interval.
Treatment. Severe or symptomatic hypocalcemia (tetany, seizures, laryngospasm, QT prolongation) is treated with IV calcium gluconate under cardiac monitoring. Replace magnesium, because hypomagnesemia impairs PTH secretion and action. Maintenance is oral calcium plus calcitriol, since without PTH the kidney cannot 1α-hydroxylate vitamin D; target a low-normal calcium to limit hypercalciuria.
| Feature | Hypoparathyroidism | Hungry bone syndrome |
|---|---|---|
| Setting | Total thyroidectomy, parathyroid injury or removal | Parathyroidectomy for severe, long-standing hyperparathyroidism; thyroidectomy for Graves disease |
| PTH | Low | Normal or high |
| Phosphate | High | Low |
| Magnesium | Usually normal | Low |
| Course | Transient or permanent | Prolonged, often weeks |
Hungry bone syndrome. When chronically high PTH falls abruptly, demineralized bone rapidly takes up calcium, phosphate, and magnesium. Treatment is aggressive IV and then high-dose oral calcium, calcitriol, and magnesium replacement.
Graves disease: preparation and thyroid storm
Preparation. Patients with Graves disease are made euthyroid with methimazole, given a β-blocker for adrenergic symptoms, and given potassium iodide (SSKI or Lugol solution) for 7–10 days before surgery. Iodide blocks hormone synthesis (the Wolff-Chaikoff effect) and release, and reduces gland vascularity and operative blood loss. Operating on an inadequately prepared hyperthyroid patient can precipitate thyroid storm.
Thyroid storm. High fever, tachycardia or atrial fibrillation, agitation or delirium, vomiting, diarrhea, and heart failure during or after surgery. Treatment combines propranolol (or esmolol), a thionamide (PTU or methimazole), iodine given at least 1 hour after the thionamide so it cannot fuel new hormone synthesis, and hydrocortisone. Cool with acetaminophen rather than aspirin, which displaces thyroid hormone from binding proteins, and treat the trigger.
Intraoperative hyperthermia with muscle rigidity and a rising end-tidal CO2 points to malignant hyperthermia, treated with dantrolene, rather than thyroid storm.
Persistent and recurrent hyperparathyroidism
Definitions. Hypercalcemia within 6 months of parathyroidectomy is persistent disease; hypercalcemia returning after more than 6 months of normocalcemia is recurrent. Persistent disease usually reflects a missed gland: an ectopic adenoma in the thymus or anterior mediastinum (inferior glands descend with the thymus), tracheoesophageal groove, thyroid, or carotid sheath, or unrecognized multigland disease such as MEN1.
Prevention and workup. Intraoperative PTH monitoring helps: a fall of at least 50% from the highest pre-excision level 10 minutes after excision predicts cure. For persistent disease, confirm the biochemistry and exclude familial hypocalciuric hypercalcemia with urine calcium, then relocalize with sestamibi SPECT/CT, 4D-CT, and ultrasound before reoperation. Reoperation carries higher risks of nerve injury and hypoparathyroidism.