INVESTIGATIONS OF HYPERTHYROIDISM - A SYSTEMATIC REVIEW (MALAYSIA 2019 MANAGEMENT OF THYROID DISORDERS CLINICAL PRACTICE GUIDELINE)

Abstract

INTRODUCTION
Hyperthyroidism is a spectrum of disorder with a rather common clinical presentation with different aetiologies. The aetiological diagnosis is important as the management differs. The aim of this review is to outline the algorithm of diagnostic testing for aetiology of hyperthyroidism.

METHODOLOGY
We examined relevant literature using a systematic PubMed search supplemented with additional hand searched articles. Of the 1151 search results, 1080 studies were removed after reviewing titles/abstracts. Finally, after reviewing 62 full texts, 22 articles were relevant to our search topic.

RESULTS
In patients with suspected hyperthyroidism, serum thyroid stimulating hormone (TSH) and free thyroxine (fT4) should be obtained at the initial evaluation. fT3 should be measured if TSH is suppressed and fT4 is within normal range. Thyroid ultrasonography with color flow doppler has reasonable sensitivity and specificity to distinguish between Graves’ disease and thyroiditis; and is recommended in situation where scintigraphy is not available or feasible (e.g. pregnancy or lactation). Meanwhile, patients with hyperthyroidism without clinical stigmata of Graves’ disease, TSH Receptor Antibody (TRAb) is useful to distinguish between Graves’ disease and other causes of hyperthyroidism. Thyroid scintigraphy should be obtained if the clinical presentation suggests a toxic adenoma or toxic multinodular goiter or whenever the diagnosis is in doubt.

CONCLUSION
The aetiology of hyperthyroidism should be determined at diagnosis. If the aetiology is not apparent based on the clinical examination, diagnostic testing should be done which includes TSH receptor antibody, thyroid scintigraphy and thyroid ultrasound with color flow doppler. However, the choice of diagnostic testing depends on the cost, availability, and local expertise.