Careful history taking and examination are required to

recognise characteristic patterns of disease. Thyroid disease and

diabetes mellitus are common and frequently familial; establishing

a detailed family history is therefore important. Some less common

endocrine disorders (such as multiple endocrine neoplasia) show

an autosomal dominant pattern of inheritance.

THE THYROID

Anatomy and physiology

The thyroid is a butterfly-shaped gland that lies inferior to the

cricoid cartilage, approximately 4 cm below the superior notch

of the thyroid cartilage (Fig. 10.1A). The normal thyroid has a

volume of <20 mL and is palpable in about 50% of women and

25% of men. It is comprised of a central isthmus approximately

1.5 cm wide, covering the second to fourth tracheal rings, and

two lateral lobes that are usually no larger than the distal phalanx

of the patient’s thumb. The gland may extend into the superior

mediastinum and can be partly or entirely retrosternal. Rarely, it

can be located higher in the neck along the line of the thyroglossal

duct, an embryological remnant of the descent of the thyroid

from the base of the tongue to its final position. Thyroglossal

cysts can also arise from the thyroglossal duct; they often occur

at the level of the hyoid bone (Fig. 10.1A) and characteristically

move upwards on tongue protrusion. The thyroid is attached to

the pretracheal fascia and thus moves superiorly on swallowing

or neck extension.

Thyrotoxicosis is a clinical state of increased metabolism caused

by elevated circulating levels of thyroid hormones. Graves’ disease

is the most common cause (Fig. 10.2 and Box 10.2). It is an

autoimmune disease with a familial component and is 5–10

times more common in women, usually presenting between 30

and 50 years of age. Other causes include toxic multinodular

goitre, solitary toxic nodule, thyroiditis and excessive thyroid

hormone ingestion.

Hypothyroidism is caused by reduced levels of thyroid

hormones, usually due to autoimmune Hashimoto’s thyroiditis,

and affects women approximately six times more commonly

than men. Most other causes are iatrogenic and include previous

radioiodine therapy or surgery for Graves’ disease.

The history

Common presenting symptoms

Neck swelling

Goitre is enlargement of the thyroid gland (Fig. 10.3). It is not

necessarily associated with thyroid dysfunction and most patients

The history • 195

10

occult nodules; thus many are found incidentally on neck or

chest imaging.

Neck pain

Neck pain is uncommon in thyroid disease and, if sudden in

onset and associated with thyroid enlargement, may represent

with goitre are euthyroid. Large or retrosternal goitres may cause

compressive symptoms, including stridor, breathlessness or

dysphagia.

Thyroid nodules may be solitary (Fig. 10.3C) or may present as

a dominant nodule within a multinodular gland. Palpable nodules

(usually >2 cm in diameter) occur in up to 5% of women and

less commonly in men, although up to 50% of patients have

A B

Hyoid bone

Sternocleidomastoid

muscle

Thyroid cartilage

Cricothyroid membrane

Cricoid cartilage

Parathyroid

Lobe of thyroid gland

Isthmus of thyroid gland

Trachea

Manubrium of the sternum

Fig. 10.1 The thyroid gland. A Anatomy of the gland and surrounding structures. B Palpating the thyroid gland from behind.

A

B

C

D

Fig. 10.2 Graves’ hyperthyroidism. A Typical facies. B Severe inflammatory thyroid eye disease. C Thyroid acropachy. D Pretibial myxoedema.

196 • The endocrine system

Past medical, drug, family and social history

Ask about:

• prior neck irradiation (risk factor for thyroid malignancy)

• recent pregnancy (postpartum thyroiditis usually occurs in

the first 12 months)

• drug therapy: antithyroid drugs or radioiodine therapy;

amiodarone and lithium can cause thyroid dysfunction

• family history of thyroid or other autoimmune disease

• residence in an area of iodine deficiency, such as the

Andes, Himalayas, Central Africa: can cause goitre and,

rarely, hypothyroidism

• smoking (increases the risk of Graves’ ophthalmopathy).

bleeding into an existing thyroid nodule. Pain can also occur in

viral subacute (de Quervain’s) thyroiditis.

History suggesting hyperthyroidism

Ask about:

• fatigue, poor sleep

• tremor, heat intolerance, excessive sweating (hyperhidrosis)

• pruritus (itch), onycholysis (loosening of the nails from the

nail bed), hair loss

• irritability, anxiety, emotional lability

• dyspnoea, palpitations, ankle swelling

• weight loss, hyperphagia, faecal frequency, diarrhoea

• proximal muscle weakness (difficulty rising from sitting or

bathing)

• oligomenorrhoea or amenorrhoea (infrequent or ceased

menses, respectively)