Thyroid
Appraise
1. Indications for thyroid surgery fall into three categories:
2. All thyroid surgery carries significant potential morbidity. Carefully investigate patients about to undergo surgery and involve the multidisciplinary team to avoid inappropriate or unnecessary surgery. Thyroid surgery is a significant potential source of litigation. As well as counselling your patient, provide clear documentation, especially with regard to potential damage to the recurrent laryngeal nerve and the parathyroid glands.
3. Thyroid surgery is increasingly performed in specialist centres by surgeons with a special interest in thyroid disorders. Closely liaise with endocrinologists and oncologists to achieve satisfactory outcomes. Joint or combined clinics are advocated, particularly for patients with complex disease.
4. It is mandatory to have access to and attend an appropriate multidisciplinary team meeting (MDT) if you regularly undertake malignant thyroid surgery. Familiarize yourself with local arrangements.
5. Be willing to work jointly with other surgical specialists, such as cardiothoracic surgeons, when treating retrosternal extensions.
6. Re-operation in the neck carries significantly increased morbidity. As a result, partial or subtotal thyroidectomy is now less frequently performed in favour of either hemi- or total thyroidectomy. The aim is to leave behind as little thyroid tissue as possible.
7. Audit your results personally, locally and nationally. In the UK results are submitted to the British Association of Endocrine and Thyroid Surgeons (BAETS).1 The Association publishes audit results and guidelines for managing thyroid disease. Familiarize yourself with the website www.baets.org.uk.
8. Assessment (see Table 20.1).
Table 20.1
| Ask yourself: | History | Examination |
| Is the patient euthyroid? | Intolerance to heat and cold, weight loss, altered bowel habit, anxiety/depression | Tachycardia, tremor, Graves’ eye signs, skin changes |
| What kind of goitre is this? | Physiologic, toxic | Diffuse, solitary nodule, multinodular |
| Is a malignant process likely? | Neck pain, hoarseness, family history of thyroid cancer, previous exposure to radiation | Lymph nodal masses, recurrent laryngeal nerve palsy, fixation, Berry’s sign (loss of carotid pulsation indicating invasion by tumour) |
| Does the patient have obstruction? | Dysphagia, shortness of breath, inability to lay flat |
Stridor, venous engorgement, Pemberton’s sign (Hugh Pemberton, 1946) – facial flushing on raising both arms indicating SVC obstruction |
| Can the goitre be delivered through the neck? | Longstanding goitre, significant obstructive symptoms |
Retrosternal extension |
Biochemical evaluation is mandatory in patients with thyroid disease. Familiarize yourself with and check thyroid function tests (tri-iodothyronine (T3), thyroxine (T4) and thyroid stimulating hormone: TSH), as well as calcium and albumin assays, prior to considering surgery. Undiagnosed or unrecognized thyrotoxicosis can lead to serious consequences during general anaesthesia. Vitamin D levels may be assayed in areas where deficiency is endemic and corrected prior to surgery. Thyroid auto-antibodies may also be requested to screen for the presence of Hashimoto’s thyroiditis (first described by Japanese physician Hashimoto Hakaru in Germany in 1912).
Fine needle aspiration cytology (FNAC) is an efficient and cost-effective method of evaluating thyroid nodules. Diagnostic accuracy is dependent on the experience of the operator, the position and type of nodule and the experience of the cytologist. Increasingly, FNAC is performed under ultrasound guidance which can be particularly beneficial in complex cysts and nodules deep within the gland. Having access to a cytologist and radiologist in the thyroid clinic (‘one-stop’ clinic), can lead to increased diagnostic accuracy (Box 20.1).
Box 20.1 Performing fine needle aspiration cytology of the thyroid gland
Gain consent verbally and explain the procedure.
Position the patient supine with neck extended.
Prepare the skin with an alcohol wipe and allow to dry.
Set up the equipment needed (22 or 24 gauge needle, 5 ml syringe, slides or cytology wash).
Fix the nodule with one hand and pass the needle through the skin into the nodule.
Smear onto glass slides and allow to either air dry or fix, depending on local protocol.
10. Indications for surgery in nodular thyroid disease:
Clinical suspicion of malignancy regardless of FNAC
Repeatedly non-diagnostic cytology (Thy 1)
Indeterminate or follicular cytology (Thy 3)
11. Your decision to recommend surgery should be based on clinical assessment in conjunction with the FNAC result and findings on imaging studies.
Prepare
It is essential to warn the patient about the risks of surgery:
1. Laryngeal nerve damage. Recurrent laryngeal nerve damage leads to a weak breathy voice and poor cough, typically described as bovine. Discuss with the patient the risk of temporary (5%) and permanent (0.5–1%) damage to the recurrent laryngeal nerve. Neuraopraxias may take several months to resolve. Referral to a voice therapist may be indicated. For patients with permanent damage, vocal cord medialization procedures may be indicated. Damage to the external branch of the superior laryngeal nerve may lead to subtle changes in voice (typically loss of high-pitched phonation). This is most evident to professional voice users and singers. Always record vocal cord function and occupation preoperatively.
2. Hypocalcaemia. Temporary hypocalcaemia occurs in up to 25% of patients following total thyroidectomy. It may be higher in patients with Graves’ disease or those with vitamin D deficiency. Permanent hypocalcaemia (requiring replacement with vitamin D and calcium) occurs in 2–5% of cases.
3. Haematoma. Haematoma rate is approximately 1%. It is higher in recurrent surgery.
4. Wound infection. Occurs in less than 1%.
5. Poor cosmesis. Hypertrophic or keloid scar formation can lead to an unsightly scar. Patients with a history of keloid formation should be counselled appropriately. You should consider using steroid injections and meticulous closure to minimize the risk.
MANAGEMENT OF THE SOLITARY THYROID NODULE AND THE DOMINANT NODULE WITHIN A MULTINODULAR GOITRE
1. Nodules within the thyroid gland are common, especially in women. Most are benign colloid nodules and/or cysts. The most common neoplasm of the thyroid gland is the thyroid adenoma. Importantly, follicular adenomas cannot be distinguished from carcinomas on the basis of cytology and as such require further diagnostic evaluation.3
