Thyroidectomy and uncontrolled graves' disease - Multidisciplinary approach prevents unnecessary cancellation.

Dear Editor,

Thyroidectomy is the definitive treatment for thyrotoxicosis for patients resistant to medical treatment and performed preferably when the patient is euthyroid.[1] Sometimes it may not be possible to render a patient euthyroid for various reasons leading to postponement or deferment of surgery.[2]

A 35-year-old woman, was suffering from Graves’ disease, confirmed by a low thyroid-stimulating hormone (<0.005 miliunits/L), markedly elevated free thyroxine (>100 nanograms/dL), and positive thyroid receptor antibodies. Thionamide (carbimazole) therapy was started to lower the circulating thyroid hormone levels and beta-blockers added to reduce her hyper-adrenergic symptoms. She developed adverse drug effects resulting in agranulocytosis which necessitated discontinuing thionamide therapy. A multidisciplinary team consisting of an endocrinologist, endocrine surgeon, and anaesthetist was convened and a consensus view emerged for urgent total thyroidectomy. In preparation for surgery Lugol’s iodine and oral propranolol 20 mg 8 hourly administered to control tachycardia. Intravenous hydrocortisone 100 mg 8 hourly was started 1 week prior to planned operation to reduce peripheral conversion of free thyroxine to free triiodothyronine.

General anaesthesia was administered with target-controlled infusion (TCI) of propofol and remifentanil with intubating dose of atracurium. Neural integrity monitor (NIM) electromyogram tracheal tube was used for intraoperative recurrent laryngeal nerve function monitoring. No further dose of atracurium was used. Anaesthesia was maintained with total intravenous anaesthesia (TIVA) using TCI devices and depth of anaesthesia was monitored with bispectral index (BIS monitor). Total thyroidectomy with parathyroid preservation was uneventful. After a brief observation in the post-anaesthesia recovery unit, she was transferred to the high dependency unit for monitoring.

The postoperative course was complicated by severe hypocalcaemia (0.82 mg/dL) due to transient postsurgical hypoparathyroidism. This was confirmed by inappropriately normal parathyroid hormone levels post-surgery despite severe hypocalcaemia. Prolonged and severe stimulation of thyroid hormone is known to induce a high bone turnover state described as thyrotoxic osteodystrophy.[34] The high incidence of hypocalcaemia after thyroidectomy in thyrotoxic patients suggests that rapid loss and sudden removal of T3 and T4 hormone stimulation and inadequate parathyroid hormone response resulting in transient post-thyroidectomy hypocalcaemia. The calcium levels stabilized over the next 3 days with intravenous calcium replacement; subsequently, she was discharged with oral calcium and vitamin D supplements.

Thyroidectomy may be the last option in some patients with Graves’ thyrotoxicosis refractory to medical treatment who cannot be optimized by medical treatment. A multidisciplinary team approach may help in appropriate preparation of patients prior to thyroidectomy avoiding unnecessary cancellation or postponement of surgery. Close postoperative monitoring of serum-ionized calcium is also recommended.

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