Does an eosinophil/monocyte ratio help to differentiate between types of thyrotoxicosis?

Poster presentation at Society of Endocrinology annual conference 2003 Background: It has been proposed that in the acute, untreated phase of thyrotoxicosis analysis of the peripheral eosinophil to monocyte ratio is a useful parameter to help differentiate thyroiditis from other forms of thyrotoxicosis without the need for radioiodine uptake scanning. (1). Methodology: We performed a retrospective search of our thyroid database for patients who had had a full blood count and radioiodine uptake scan prior to the commencement of antithyroid medication. Results: Fifty-nine cases fulfilled the criteria; the diagnoses by radioiodine uptake scanning were 25 Graves' disease, 19 nodular thyroid disease, 5 thyroiditis, 4 amiodarone associated thyrotoxicosis and 6 were normal. The peripheral eosinophil and monocyte percentages did not show any significant differences between the thyroiditis and Graves' group (eosinophil p =0.82,monocytes p= 0.33). The amiodarone group (n=4) had a significant increase in monocytes (p=0.04) in comparison to those with normal radioiodine uptake scans (n=6), eosinophil levels in the same groups tended to be lower in the amiodarone group but this did not reach statistical significance.(p=0.07). The eosinophil/monocyte ratio of the thyroiditis group did not show any significant difference to the ratios attained by the Graves', nodular thyroid, amiodarone related or normal groups. (p= 0.9,0.69,0.19 and 0.33 respectively). Only five of our patients had an eosinophil/monocyte ratio of greater than 1.0, three had Graves' disease (sensitivity 12%, specificity 60%), one had nodular thyroid disease and one had a normal radioiodine uptake scan. Seventeen patients had an eosinophil/monocyte ratio less than 0.2, 9 were secondary to Graves' disease (53%), 2 thyroiditis (12%), 4 nodular thyroid disease (24%) and 2 amiodarone associated thyrotoxicosis (12%). Conclusion: In this group calculation of the eosinophil/monocyte ratio in untreated thyrotoxicosis is not helpful in differentiating between thyroiditis and Graves' thyrotoxicosis. 1.Izumi Y et al,(2002) Clinical Endocrinology 57 51-59 -------------------------------------------------------------------------------- Endocrine Abstracts (2003) 5 P276