ANSWER 85
Although anxiety might produce some of these symptoms and signs, they fit much better
with a diagnosis of hyperthyroidism. The neck should be examined carefully and in this case
there was a smooth goitre with no bruit over it. Blood tests showed a very low thyroxine-
stimulating hormone (TSH) level and a high free thyroxine (T 4 ), confirming the diagnosis of
hyperthyroidism due to a diffuse toxic goitre (Graves’ disease). Hyperthyroidism may mimic
an anxiety neurosis with marked restlessness, irritability and distraction. The most helpful
discriminatory symptoms are weight loss despite a normal appetite and preference for cold
weather. The most helpful signs are goitre, especially with a bruit audible over it, resting sinus
tachycardia or atrial fibrillation, tremor and eye signs. Eye signs which may be present
include lid retraction (sclera visible below the upper lid), lid lag, proptosis, oedema of the eye-
lids, congestion of the conjunctiva and ophthalmoplegia. Atypical presentations of thyrotox-
icosis include atrial fibrillation in younger patients, unexplained weight loss, proximal
myopathy or a toxic confusional state. The weakness here is suggestive of a proximal myopa-
thy. The very low TSH level indicates a primary thyroid disease rather than overproduction of
TSH by the anterior pituitary.
- Diffuse toxic goitre (Graves’ disease)
- Toxic nodular goitre
multinodular goitre (Plummer’s disease)
solitary toxic adenoma - Over-replacement with thyroxine
! Common causes of hyperthyroidism
Blood should be sent for thyroid-stimulating immunoglobulin which will be detected in
patients with Graves’ disease. Medical treatment for thyrotoxicosis involves the use of the
antithyroid drugs carbimazole or propylthiouracil. These are given for 12–18 months but
there is a 50 per cent chance of disease recurrence on stopping the drugs. If this happens
radioiodine or surgery is indicated. Beta-blockers can be used to rapidly improve the symp-
toms of sympathetic overactivity (tachycardia, tremor) while waiting for the antithyroid
drugs to act. Radio-iodine is effective but there is a high incidence of late hypothyroidism.
Surgery is indicated if medical treatment fails, or if the gland is large and compressing sur-
rounding structures. In severe exophthalmos there is a risk of corneal damage and ophthal-
mological advice should be sought. High-dose steroids, lateral tarsorrhaphy or orbital
decompression may be needed.
- Thyrotoxicosis may be difficult to differentiate from an anxiety state.
- The commonest causes of hyperthyroidism are Graves’ disease or a toxic nodular goitre.