Thyroid Disease

Overview

The thyroid gland produces, stores, and secretes thyroxine (T4) and triiodothyronine (T3) through a negative feedback process involving the hypothalamus and pituitary gland. Thyroid dysfunction can result when any part of this process is affected. Accurate interpretation of thyroid function test is essential looking mainly at high or low TSH and free thyroid hormone levels

Graves Disease
Hypothyroidism
Goitre and Nodules
Thyroiditis
Thyroid Tumours

Investigations

Thyroid Function Test (TSH, T3, T4)
Antibody Screen

Antibodies in Autoimmune thyroid disease
Conditions	Anti-TPO	Antithyroglobulin	TSH receptor antibody
Grave’s Disease	70-80%	30-50%	70-100%
Hashimoto’s Disease	95%	60%	10-20%

Scintiscanning
Ultrasound
Fine needle aspiration
CT

Side Note Scintiscanning enables localization of sites of accumulation of radioiodine or sodium pertechnetate [99mTc], which gives information about the activity of the iodine trap. This can help assess hypo or hyperthyroid function. It can be useful to differentiate among causes of thyrotoxicosis. It may also provide information about the size and shape of the thyroid gland.