Endocrine Abstracts

Background: Subclinical hyperthyroidism provides a challenging condition in clinical endocrinology. The debate about who and when to treat has long been discussed. Despite guidelines describing assessment of such patients, there is surprising little data on imaging in this condition and the role of nuclear medicine or ultrasound scans.

Aim: To review all patients with subclinical hyperthyroidism referred for imaging studies at a district general hospital to ascertain any trends or abnormalities in clinical practice.

Method: All patients attending Royal Wolverhampton Hospital between 2007 and 2013 who had a nuclear medicine thyroid uptake scan or ultrasound of the thyroid and with a diagnosis of subclinical hyperthyroidism were retrospectively analysed. Patient’s blood tests were reviewed prior to the scan ensuring biochemically they remained subclinical.

Results: Forty patients were identified, mean age 67.3 years (range 30–91 years). 27 patients had nuclear medicine scans of which 63% (17 patients) had evidence of increased uptake in a focal area. 23 patients had an ultrasound of the thyroid with 15 showing multinodular goitre and five showing a solitary nodule. ten patients (25%) had both scans with six patients having correlation and indicating functionality. 29 (72.5%) patients had TPO antibodies assessed of which only three were elevated. ten patients (25%) had an undetectable TSH, mean T₄ levels were 15.9 pmol/l (10.6–21), mean T₃ levels were 4.6 pmol/l (3.2–5.9).

Conclusion: The findings provide an understanding of the characteristics of patients referred for imaging. Nuclear medicine scans provided more clinically beneficial results than ultrasound imaging, though paired imaging was best at guiding treatment. Nuclear medicine scans are important in deciding whether to treat patients with biochemical evidence of subclinical hyperthyroidism and should be part of routine assessment.