Endocrine Abstracts

Introduction: Methimazole is the thionamide compound most used in the treatment of hyperthyroidism due to its efficacy, commodity and security. Severe side effects are rare, although potentially fatal: agranulocytosis in 0.1–0.5% and toxic hepatitis in 0.1%

Aims: To characterize the patients admitted in the endocrinology ward for the last 10 years for severe complications of methimazole therapy.

Material and Methods: Retrospective analysis of clinical, laboratorial, radiological data, type of therapy and outcome of all the patients admitted in our department between January/2003 and July/2012, using SPSS 21.0^®.

Results: Were studied five patients, mean age 68.6±14.9 years. Hyperthyroidism was caused by Graves’ disease in three cases, toxic adenoma in one patient and mixed-type amiodarone-induced hyperthyroidism in other patient. Clinical presentation, laboratory, ultrasonography and ^99mTc thyroid scintigraphy compatible with thyrotoxicosis. Patients were treated with 21±6.5 g/day of methimazole for 45.4±22.7 days. Admitted for: leukopenia with relative neutrophilia in one patient(leukocytes=240/μl, neutrophils=64%), agranulocytosis in three patients(mean neutrophil counting=156.6±37.9/μl) and toxic hepatitis in other(AST=353 U/l(30–65), ALT=509 U/l(30–65), ALP=166 U/L(35–104), GGT=269 U/L(5–36)). Clinically: fever without focus in two patients, oropharyngeal and esophageal candidiasis in two cases, septic shock in other patient. Treatment consisted of: methimazole suspension in every patient (n=5), i.v. broad spectrum antibiotics(n=5), i.v. antifungal therapy(n=2), i.v. corticosteroids(n=2), granulocyte macrophage colony-stimulating factor(GM-CSF 30 MUI/day, 5 days)(n=2). Mean duration of ward admition was 20.2±4.1 days; favourable clinical and laboratorial outcome in every case. For hyperthyroidism therapy, three patients received ¹³¹I(11.3±4.1 mCI), one patient had spontaneous remission, other patient suspended amiodarone and was started on dexamethasone 48 mg/day with progressive dose reduction. Follow-up after 11.1±4.3 months: four patients euthyroid and one with hypothyroidism after radioiodine therapy, under thyroxine 125 μg/day.

Conclusions: This cohort represents the rarity of methimazole’s serious toxicity (five patients in 10 years). However, we stress the severity of the side effects, occurring in an early stage of therapy (45.4±22.7 days). Timely diagnosis depends on close monitoring and high level of clinical suspicion.