Thyrotoxicosis or hyperthyroidism

Hyperthyroidism, or thyrotoxicosis, refers to thyroid overactivity of any cause. Diagnosis is often clinical, but antibody testing may help identify the cause.

General examination

To diagnose thyrotoxicosis or hyperthyroidism a detailed and full general examination is mandatory in the initial assessment of all patients.

Body habitus, weight and BMI

Weight loss is common with thyrotoxicosis and should improve rapidly with treatment.

Weight loss will also occur with the development of Addison's disease or with type 1 diabetes mellitus.

Cardiovascular system

Detailed cardiac assessment is necessary.

Tachycardia, atrial fibrillation and other arrhythmias may occur in thyrotoxicosis.

Hypertension is also commonly seen with thyrotoxicosis.

Orthostatic hypotension may occur, but may also indicate glucocorticoid deficiency with Addison’s disease.

Congestive cardiac failure may complicate both hyperthyroidism and hypothyroidism due to cardiomyopathy, or rate related failure.

Eyes: lid retraction and lid lag

Lid retraction and lid lag may be seen in any cause of thyrotoxicosis.

Lid retraction may be obvious at rest with the whites of the eyes visible above the iris. Any asymmetry of the eyes is suggestive of Graves' disease.

Ask the patient to watch your horizontal finger as you very slowly lower it about 30cm away from their eyes. Delay in the upper eye lid following downward gaze will reveal the whites of the eye above the iris in the presence of lid lag.

Grave's ophthalmopathy

Inspect the eyes carefully.

Any asymmetry suggests Graves' disease as the cause of thyroid dysfunction.

Swelling of the soft tissue around the eyes, redness of the whites of the eyes (conjunctival injection) or protrusion, lid asymmetry or muscle tethering all indicate Graves' ophthalmopathy.

Examine the open and closed eyes from the side and above. Protrusion of one or both eyes is known as proptosis or exophthalmos.

Ask the patient to close their eyes and ensure there is no cornea visible indicating full lid closure.

Test external ocular movements. Diplopia in any direction, and any loss of movement or frank ophthalmoplegia are usually due to muscle tethering.  

Acuity should also be tested. Drop in acuity in Graves' disease may indicate increased orbital pressure on the optic nerve which requires urgent assessment for decompression.

Skin and hair

Pallor may also occur with anaemia and glucocorticoid deficiency of any cause, for example pernicious anaemia, coeliac disease or pituitary dysfunction.

Deeply tanned skin with pigmentation of scars may indicate Addison’s disease.

Loss of secondary sexual hair may occur in gonadotropin deficiency.

Patches of symmetrical depigmentation of both hair and skin may occur with vitiligo.

Patches of complete hair loss indicate associated alopecia areata.

Pretibial myxoedema - pinkish discolouration over thinned and yellow tinged skin with or without oedema - may occur with auto-immune thyroid disease.

Hands and tremor

Examine the palms - hot, red and sweaty hands occur in hyperthyroidism.

Ask the patient to hold out their hands in front of them. A resting tremor is usually obvious in hyperthyroidism, but may be highlighted by placing a sheet of paper over the hands to demonstrate it shaking.

Reflexes

Brisk reflexes are seen in hyperthyroidism, as is a general increase in resting movement.

Look for 'jumpiness' in the patient during examination.

Musculature

Proximal myopathy may occur with alterations in thyroid function. Ask the patient to slowly rise from a squatting position with a straight back and without using their arms or levering their upper body to help.

Muscle wasting may also occur in glucocorticoid deficiency.

Thyroid gland, neck and nodes

Thyrotoxicosis is most commonly due to Grave's disease, multinodular goitre or a thyroid nodule.

First inspect the neck from the front and ask the patient to swallow. Diffuse thyroid swelling, nodules, cysts and multinodular goitres may all be obvious as anterior neck masses that move on swallowing.

Examine the neck thoroughly. This is usually performed from behind the seated patient and in a systematic fashion. The texture of the gland, tenderness, and the presence or absence nodularity or of distinct lumps or lymph nodes must be noted.

A Graves' gland will typically be diffusely and modestly enlarged. It may also be warm, minimally tender and with an audible bruit in very active disease.

Nodules are easily palpable, should be noted as single, multiple or dominant. Ask the patient to swallow while palpating any nodules, and ensure to check for associated lymphadenopathy.