Amiodarone-induced thyrotoxicosis due to destructive thyroiditis: therapeutic recommendations.
BACKGROUND
Amiodarone-induced thyrotoxicosis (AIT) type 1 occurs in subjects with an underlying thyroid disease, whereas type 2 AIT is a form of destructive thyroiditis. Our hypothesis was that the common practice of thyroid testing before prescription of amiodarone would reduce the incidence of pure type 1 AIT, though a stringent classification may be difficult (mixed type AIT).


METHODS
Thyroid testing before and after treatment of AIT (n = 12) and the response to combined antithyroid and glucocorticoid treatment (n = 11) were recorded in a consecutive series of patients seen at a university hospital.


RESULTS
Some criteria for type 1 AIT were fulfilled in 3 patients, but the diagnosis of a mixed form AIT was more likely in 2 of these. Type 2 AIT was diagnosed in the other 9 patients, while 6 patients had diffuse hypoechoic goitre. The median time to euthyroidism (defined as normal fT3 concentration) under thionamide and prednisolone (starting dose 20 to 75 mg/d) was 2 months (interquartile range 1 to 2.7 months). Thionamide treatment was stopped after a median duration of 5.7 months (interquartile range 4.2 to 8.7 months) and glucocorticoids were completely withdrawn after 6.7 months (5.5 to 8.7 months).


CONCLUSIONS
Nowadays, isolated type 1 AIT is rarely found and destructive thyroiditis (as type 2 AIT or mixed form) is the predominant cause of AIT. To accelerate recovery, we prescribed thionamide and glucocorticoids simultaneously as first-line therapy once contraindications for the use of steroids had been ruled out.
Dietlein
M
M
Department of Nuclear Medicine, University of Cologne, Cologne, Germany. markus.dietlein@uni-koeln.de
Schicha
H
H
D000328:Adult; D000368:Aged; D000638:Amiodarone / Q000008:administration & dosage / Q000009:adverse effects*; D013956:Antithyroid Agents / Q000627:therapeutic use*; D002231:Carbimazole / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008713:Methimazole / Q000627:therapeutic use; D008875:Middle Aged; D011239:Prednisolone / Q000627:therapeutic use; D011446:Prospective Studies; D013966:Thyroiditis / Q000150:complications* / Q000175:diagnosis* / Q000188:drug therapy; D013971:Thyrotoxicosis / Q000139:chemically induced* / Q000175:diagnosis* / Q000188:drug therapy / Q000517:prevention & control; D016896:Treatment Outcome
D013956:Antithyroid Agents; D005938:Glucocorticoids; D008713:Methimazole; D002231:Carbimazole; D011239:Prednisolone; D000638:Amiodarone