Problems of childhood. Consultation, diagnosis, and management.

Hypothyroidism There is general agreement that all patients with symptomatic hypothyroidism should receive replacement treatment. MANAGEMENT Thyroxine should be used in the routine management of hypothyroidism. The initial dose should not exceed 0-05 mg daily in patients over 40; an initial dose of 0-1 mg daily may be used in younger patients. The dose should be increased by increments until the patient is clinically and biochemically euthyroid. The optimum dose varies between 0 1 and 0-2 mg daily and higher doses are very rarely required. There is no need for triiodothyronine or tablets combining thyroxine and tri-iodothyronine in routine management, since these confer no additional symptomatic benefit, side effects are more common, and serum triiodothyronine levels are normal on thyroxine as there is a substantial extrathyroidal conversion of thyroxine to triiodothyronine. A raised serum thyroxine concentration is not, therefore, an essential prerequisite for adequate replacement treatment as has been claimed. There is only one particular indication for the long-term maintenance of a patient on tri-iodothyronine in preference to thyroxine: in patients who have had total thyroid ablation for thyroid carcinoma treatment should be stopped at regular intervals so that scanning procedures can be carried out. The replacement treatment can be discontinued for a considerably shorter time if triiodothyronine is used. It is important to ensure that adequate hormone is given to suppress thyroid-stimulating hormone secretion in these patients since this is a major part of their management. Replacement treatment with thyroxine must be introduced cautiously in patients with ischaemic heart disease, in whom it may not be possible to give full replacement doses. The addition of a beta-adrenergic blocker such as propranolol, which can be increased incrementally with the thyroxine, may allow patients with angina pectoris to tolerate a larger dose of thyroxine than would otherwise be possible. There is no general agreement on the best treatment for hypo-thyroid (myxoedema) coma. It is common practice to give thyroxine in doses of 0 05 mg daily by mouth combined with triiodothyronine 20-40 Htg daily by intramuscular injection together with hydrocortisone hemisuccinate 100 mg twice daily. Supportive treatment with fluids, assisted respiration, and treatment for cardiac failure or arrhythmias should be provided. The body temperature should be slowly raised to normal. It must be remembered that over-enthusiastic therapeutic activity can be as dangerous as inactivity in patients with coma. The monthly MIMS index of proprietary preparations available in Britain includes the following …