Benign Thyroid Disease

49 Benign Thyroid Disease

49.1 Clinical Features

• Multinodular, simple (smoothly enlarged), retrosternal goitres

• Increased where iodine is deficient

• Long-standing may develop clinical or subclinical thyrotoxicosis

• Symptoms

figure Neck swelling

figure Dyspnea

figure Dysphagia

figure Choking

figure Stridor

49.2 Epidemiology

• Ethnicity

figure No racial predilection exists

• Incidence

figure Multinodular goitres is one of the common endocrine conditions, affecting 500 million people worldwide

• Sex

figure F:M 5:1

figure In the Wickham study, 26% of women had a goitre compared with 7% of men

figure Thyroid nodules are less frequent in men than in women, but when found, they are more likely to be malignant

• Age

figure The frequency of goitres decreases with advancing age

figure The decrease in frequency differs from the incidence of thyroid nodules, which increases with advancing age

• Aetiology

figure Iodine deficiency

figure Autoimmune thyroiditis—Hashimoto or postpartum thyroiditis

figure Excess iodine (Wolff–Chaikoff effect) or lithium ingestion, which decrease release of thyroid hormone

figure Goitrogens, e.g., propylthiouracil, lithium, carbamazepine

figure Stimulation of thyroid stimulating hormone (TSH) receptors by TSH from pituitary tumours, pituitary thyroid hormone resistance, gonadotropins, and/or thyroid-stimulating immunoglobulins

figure Inborn errors of metabolism causing defects in biosynthesis of thyroid hormones

figure Exposure to radiation

figure Deposition diseases

figure Thyroid hormone resistance

figure Subacute thyroiditis (de Quervain thyroiditis)

figure Silent thyroiditis

figure Riedel thyroiditis

figure Infectious agents

– Acute suppurative—bacterial

– Chronic—mycobacteria, fungal, and parasitic

figure Granulomatous disease

figure Thyroid malignancy

49.3 Simple Goitres (Fig. 49.1)

• Physiological

figure Puberty

figure Pregnancy

figure oral contraceptive pill (OCP)

• Pathological—iodine deficiency

• Medical treatments

figure Radioactive iodine:

– Up to 50% reduction in goitre volume

– Risks include: hypothyroidism, Graves

– Contraindicated in pregnant women or women wanting to get pregnant within 1 year of treatment

figure Suppression therapy:

– Thyroxine administration decreases TSH leading to a reduction in volume

– Risks include: thyrotoxicosis, cardiac arrythmias, thyroid increases to pretreatment size on cessation of thyroxine, osteopenia in long-term thyroxine use

figure Antithyroid medication:

– Indicated for thyrotoxic patients, e.g., propylthiouracil (side effects: rash and agranulocytosis)

– 50% relapse rate

• Retrosternal goitre

figure May present with dyspnea, stridor that is positional/nocturnal, or coincidentally on chest X-ray with shadowing in upper mediastinum

figure Clinically:

– Inability to palpate below it

– Dullness to percussion over sternum

– May only be a small cervical component

– Pemberton sign: facial flushing after raising both arms in the air due to compression of jugular veins by thyroid

figure Investigations:

– CT scan good for demonstrating retrosternal extent ± tracheal compression

– Spirometry

figure Treatment:

– Conservative (if medically unfit)

– Surgery: most can be removed via cervical route (unless below aortic arch) may need cardiothoracic input ± sternotomy

– Increasing role of radioactive iodine in euthyroid retrosternal goitre safe to use down to a tracheal diameter of 1 cm

49.3.1 Toxic Goitres

49.3.2 Clinical Features

• Graves disease

figure Most common

figure One or more:

– Thyrotoxicosis

– Goitre

– Eye signs: lid lag, exophthalmos, chemosis

– Skin signs: acropachy, pretibial myxedema

figure Autoimmune with thyroid antibodies

figure 15% family history

figure F>M 5:1; middle ages

figure Treatments:

– Radioactive iodine

– Antithyroid drugs, e.g., carbimazole or propylthiouracil

– Block and replace: antithyroid drugs full dose + thyroxine to replace thyroid function

– Surgery

• Solitary toxic nodule

• Long-standing MNGs (Plummer disease)

49.3.3 Treatment

• 50% of patients relapse on carbimazole/propylthiouracil—may request thyroidectomy

• When considering surgery need to achieve euthyroid state preop with antithyroid medication, β-blockade and Lugol iodine (up to 2 weeks preop)

figure

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Jul 4, 2016 | Posted by in OTOLARYNGOLOGY | Comments Off on Benign Thyroid Disease

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