HYPERTHYROIDISM . (thyroid over activity, thyrotoxicosis). It 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.
(thyroid over activity, thyrotoxicosis)
It is common, affecting perhaps 2-5% of all females at some time and with a sex ratio of 5 : 1.
Proptosis and lid lag.
Waxy infiltrative plaques and edema,consistent
with infiltrative dermopathy of Grave’s disease.
Toxic solitary adenoma/nodule (Plummer's disease):
It occures in some elderly patients ,the clinical presentation is more like hypothyroidism, with very few signs and so, high degree of clinical suspicion is essential.
Warm, moist skin,palmarerythema, onycholysis, and, less commonly, urticaria, and diffuse hyperpigmentation may be evident.
The usual daily maintenance doses of antithyroid drugs in the titration regimen are 2.5–10 mg of carbimazole or methimazole and 50–100 mg of propylthiouracil.
1. Review after 4-6 weeks and reduce dose of carbimazole depending on clinical state and T4/T3 levels. TSH levels may remain suppressed for several months and are unhelpful at this stage.
2. When clinically and biochemically euthyroid, stop beta-blockers.
3. Review after 2-3 months and, if controlled, reduce carbimazole.
4. Gradually reduce dose to 5 mg daily over 6-24 months if hyperthyroidism remains controlled.
5. When the patient is euthyroid on 5 mg daily carbimazole, discontinue.
About 50% of patients will relapse after a course of carbimazole or propylthiouracil, mostly within the following 2 years but occasionally much later.
Propylthiouracil has a prolonged radioprotective effect and should be stopped several weeks before radioiodine is given, or a larger dose of radioiodine will be necessary.
Exacerbation of ophthalmopathy can be avoided by the use of prednisone, 40 mg/d, at the time of radioiodine treatment, tapered over 2–3 months.
Hypothyroidism occurs in about 10% of patients within 1 year, and this percentage increases with time. It is likeliest if TPO antibodies are positive.
Indications for either surgery or radioiodine are:
Thyroid crisis or 'thyroid storm'
Fetal heart rate provides a direct biological assay of fetal thyroid status, and monitoring should be performed at least monthly. Rates above 160 per minute are strongly suggestive of fetal hyperthyroidism, and maternal treatment with carbimazole and/or propranolol may be used.
If necessary (high doses needed, poor patient compliance or drug side-effects), surgery can be performed, preferably in the second trimester.
Swelling and oedema of the extraocular muscles lead to limitation of movement and to proptosis which is usually bilateral but can sometimes be unilateral.
There is periorbitaloedema and conjunctivaloedema and inflammation.
Treatment of the eyes may be either local or systemic, and always requires close liaison between specialist endocrinologist and ophthalmologist:
Irradiation of the orbits (20 Gy in divided doses) is used in severe instances. This improves inflammation and occular motility but has little effect on proptosis.