Improving the accuracy of clinical diagnosis in hyperthyroid disorders using ultrasound assessment
Jessica Triay & Parag Singhal
Background: Thyroid ultrasound (US) is not routinely used in the evaluation of hyperthyroidism, although studies show that clinical exam may miss lesions up to 2 cm in diameter. We reviewed our departments practice of thyroid US to consider (1) accuracy of our clinical diagnosis and (2) whether this could improve management. Our hospital has no facility for isotope scanning.
Methods: Seventy-three cases (13 male, 60 female) identified from thyroid US requests. Clinical notes, thyroid autoantibodies and fine needle aspiration (FNA) reviewed, excluding those with thyroid imaging prior to consultation and Amiodarone related disease.
Results: Clinical diagnoses 24 Graves disease, 21 Multinodular disease (MND), 2 postpartum thyroiditis, 2 transient thyroiditis, 20 no clear diagnosis.
i) Graves. Of 24 clinical cases only 7 had consistent US and antibody findings.
ii) MND. Of 21 clinical cases 18 had ultimate diagnosis of MND
iii) Overlap. 9 had US features of MND and positive antibodies
iv) Dissociation. 6 had US features of Graves but negative antibodies
v) Missed solitary/dominant nodule in 3 cases of clinical Graves (all antibody negative). 1 solitary nodule missed in no clear diagnosis group.
Conclusions: Palpation can miss important thyroid abnormalities. Accurately diagnosing Graves disease is challenging, but, as up to 80% of this patient group may be treated with antithyroid drugs alone, this is current first line practice in Europe. Multinodular and autoimmune thyroid changes can coexist, making it unclear which disease process predominates and what the natural course may be. Knowledge of multinodular changes may prompt earlier recommendation of definitive therapy to avoid relapse (radioactive iodine or surgery). Ultrasound is simple, widely available and inexpensive. Knowledge of the underlying problem can be used to facilitate treatment discussions with patients for improved informed decision making, which may reduce follow up time.