Goitre is more common in women than in men and may be either physiological or pathological.
Most commonly a goitre is noticed as a cosmetic defect by the patient or by friends or relatives. The majority are painless but pain or discomfort can occur in acute varieties. Goitres can produce dysphagia and difficulty in breathing, implying oesophageal or tracheal compression. Clinical examination should record the size, shape, consistency and mobility of the gland as well as whether its lower margin can be demarcated (thus implying the absence of retrosternal extension). A bruit may be present. Associated lymph nodes should be sought and the tracheal position determined if possible. Examination should never omit an assessment of the patient’s clinical thyroid status.
There is a WHO grading of goitre:
GRADE 0 No palpable or visible goitre
GRADE 1 Palpable goitre
1A Goitre detectable only on palpation
1B Goitre palpable and visible with neck extended
GRADE 2 Goitre visible with neck in normal position
GRADE 3 Large goitre visible from a distance
Specific enquiry should be made about any medication, especially iodine-containing preparations, and possible exposure to radiation.
Two facts are essential about any goitre: its pathological nature and the patient’s thyroid status. The nature can often be judged clinically. Goitres are usually separable into diffuse and nodular types, the causes of which differ.
Particular points of note are:
PUBERTY AND PREGNANCY may produce a diffuse increase in size of the thyroid.
IN GRAVES’ DISEASE (autoimmune hyperthyroidism) the gland is again diffusely enlarged, often somewhat firm and frequently associated with a bruit.
ACUTE TENDERNESS in a diffuse swelling, sometimes with severe pain, is suggestive of an acute viral thyroiditis (de Quervain’s). This is usually associated with a systemic viral illness and may produce transient clinical hyperthyroidism with an increase in serum T. PAIN in a goitre may be caused by thyroiditis, bleeding into a cyst or (rarely) a thyroid tumour.
SIMPLE GOITRE: in this instance no clear cause is found for enlargement of the thyroid, which is usually smooth and soft. It may be associated with thyroid growthstimulating antibodies.
NODULAR GOITRES may have multiple or solitary nodules. Commonest is the multinodular goitre, especially in older patients. The patient is usually euthyroid but may be hyperthyroid. Multinodular goitre is the commonest cause of tracheal and/or oesophageal compression and may cause laryngeal nerve palsy. It may also extend retrosternally.
SOLITARY NODULES present a difficult problem. A history of pain, rapid enlargement or associated lymph nodes in such a situation suggests the possibility of thyroid carcinoma. The majority of such nodules are, however, cystic or benign and, indeed, may simply be the largest solitary nodule of a multinodular goitre. Risk factors for malignancy include previous irradiation, long-standing iodine deficiency and occasional familial cases. Solitary toxic nodules (Plummer’s syndrome) are quite uncommon and may be associated with TJ production.
FIBROTIC GOITRE (Riedel’s thyroiditis): this rare condition, usually producing a ‘woody’ gland, is associated with other midline fibrosis and is often difficult to distinguish from carcinoma, being irregular and hard.
EXCESSIVE DOSES OF CARBIMAZOLE OR PROPYLTHIOURACIL will induce goitre.
IODINE DEFICIENCY AND DYSHORMONOGENESIS can also cause goitre.
MALIGNANCY. Rarely the thyroid is the site of a metastatic deposit or the site of origin of a lymphoma.
Acute (de Quervain’s thyroiditis)
Chronic fibrotic (Riedel’s thyroiditis)
Iodine deficiency (endemic goitre)
Goitrogens (e.g. sulphonylureas)
Clinical findings will dictate appropriate initial tests: THYROID FUNCTION TESTS-TSH plus T. or TJ
CHEST AND THORACIC INLET X-RAYS where appropriate to detect tracheal compression and large retrosternal extensions.
FINE NEEDLE ASPIRATION (FNA). In patients with a solitary nodule or a dominant nodule in a multinodular goitre, there is a 5% chance of malignancy; in view of this, FNA should be performed. This can be done in the outpatient clinic. Cytology in expert hands can usually differentiate the suspicious or definitely malignant nodule.
ULTRASOUND with high resolution is a sensitive method for delineating nodules and can demonstrate whether they are cystic or solid. Unfortunately, even cystic lesions can be malignant and therefore FNA is the preferred technique.
THYROI D SCAN (1251 or 1311) is useful to distinguish between functioning (hot) or non-functioning (cold) nodules. A hot nodule is virtually never malignant; however a cold nodule is malignant in 10% of cases. FNA has therefore reduced the need for imaging and will reduce the necessity for surgery.
During puberty and pregnancy a goitre associated with euthyroidism rarely requires intervention. If euthyroid, the patient should be reassured that spontaneous resolution is likely. In other situations the patient should be rendered euthyroid.
Indications for surgical intervention are:
THE POSSIBILITY OF MALIGNANCY. A history of rapid growth, pain, cervical lymphadenopathy or previous irradiation to the neck are worrying features. FNA should be performed. Surgery may be necessary.
PRESSURE SYMPTOMS on the trachea or, more rarely, oesophagus. The possibility of retrostemal extension should be excluded.
COSMETIC REASONS. A large goitre is often a considerable anxiety to the patient even though functionally and anatomically benign.
The different types of thyroid carcinoma, their characteristics and treatment are listed. The tumour is relatively uncommon, being responsible for 400 deaths annually in the UK. Particular points are:
PAPILLARY AND FOLLICULAR CARCINOMAS may take up iodine, shown by scanning. Such patients after total thyroidectomy may be given a therapeutic radioiodine dose, which will be taken up by remaining thyroid tissue or metastatic lesions. Replacement T. will subsequently be needed and should suppress TSH, which may otherwise stimulate any residual differentiated carcinoma. Lungs and bone are the commonest sites of metastases, while local invasion is often a problem. The measurement of thyroglobulin in plasma has been used as a tumour marker for the presence of neoplastic tissue.
ANAPLASTIC CARCINOMAS AND LYMPHOMA do not respond to radioactive iodine.
MEDULLARY CARCINOMA, often associated with MEN, is usually treated by total thyroidectomy. The patient’s family should be screened for this and other endocrine neoplastic conditions.
Hyperthyroidism is common, affecting perhaps 2-5% of all females at some time and with a sex ratio of 5 : 1, most often between ages 20 and 40 years. Nearly all cases are caused by intrinsic thyroid disease; a pituitary cause is extremely rare.
ATHOGENESIS. This is the commonest cause of hyperthyroidism and is due to an autoimmune process. Serum IgG antibodies bind to the thyroid TSH receptor stimulating thyroid hormone production, behaving like TSH. These TSH receptor antibodies can be measured in serum. There is an association with HLA-B8, Dw3 and 50% concordance is seen amongst monozygotic twins with a 5% concordance rate in dizygotic twins. Yersinia enterocolitica as well as Escherichia coli and other Gram-negative organisms contain TSH binding sites. This raises the possibility that the initiating event in the pathogenesis may be an infection in a geneticallysusceptible individual.
Associated with the thyroid disease in many cases are eye changes (see below) and other signs such as vitiligo and pretibial myxoedema. Rarely lymphadenopathy and splenomegaly may occur. Graves’ disease is also associated with other autoimmune disorders such as pernicious anaemia and myasthenia gravis.
The natural history is one of fluctuation, many patients showing a pattern of alternating relapse and remission; perhaps only 40% of subjects have a single episode. Many patients eventually become hypothyroid.
Solitary toxic nodule/adenoma
Toxic multinodular goitre
Thyrotoxicosis factitia (secret T4 consumption)
Metastatic differentiated thyroid carcinoma
TSH-secreting tumours (e.g. pituitary)
Hyperfunctioning ovarian teratoma (struma ovarii)
Only the first three are common.
HCG, human chorionic gonadotrophin
Toxic solitary adenoma/nodule (Plummers disease) This is the cause of about 5% of cases of hyperthyroidism. It does not usually remit after a course of antithyroid drugs.
Toxic multinodular goitre
This commonly occurs in older women; again antithyroid drugs are rarely successful in inducing a remission.
De Quervain’s thyroiditis
This is transient thyrotoxicosis from an acute inflammatory process, probably viral in origin. Apart from the toxicosis there is usually fever, malaise and pain in the neck with tachycardia and local thyroid tenderness. Thyroid function tests show initial thyrotoxicosis, the erythrocyte sedimentation rate (ESR) is raised and thyroid scans show suppression of uptake in the acute phase, though hypothyroidism, usually transient, may then follow after a few weeks. Treatment of the acute phase is with aspirin, using short-term prednisolone in severely symptomatic cases.
CLINICAL FEATURES OF HYPERTHYROIDISM
The symptoms of hyperthyroidism affect many systems; they and relevant signs. Symptomatology and signs vary with age and with the underlying aetiology. Important points are:
THE EYE SIGNS, PRETIBIAL MYXOEDEMA AND
THYROID ACROPACHY only occur in Graves’ disease.
Pretibial myxoedema is an infiltration on the shin, essentially only occurring with eye disease. Thyroid acropachy is very rare and consists of clubbing, swollen fingers and periosteal new bone formation.
IN THE ELDERLY a frequent presentation is with atrial fibrillation, other tachycardias and/or heart failure, often with few other signs. Thyroid function tests are mandatory in any patient with unexplained atrial fibrillation.
CHILDREN frequently present with excessive height or excessive growth rate, or with behavioural problems such as hyperactivity. They may also show weight gain rather than loss.
SO-CALLED ‘APATHETIC THYROTOXICOSIS’ in some elderly patients presents with a clinical picture more like hypothyroidism. There may be very few signs and a high degree of clinical suspicion is essential.