Methimazole associated eosinophilic pleural effusion: a case report

Abstract

BackgroundAdverse reactions associated to anti-thyroid drugs include fever, rash, arthralgia, agranulocytosis and hepatitis that are thought to be hypersensitivity reactions. Five cases of pleural effusion associated to thionamides have also been reported, two with propylthiouracil and three with carbimazole.Case presentationWe report here a case of a 75-year-old man admitted because of unilateral pleural effusion. The patient had a recent diagnosis of hyperthyroidism and 6 days after starting methimazole complained of pleuritic chest pain. He had elevated C-reactive protein and erythrocyte sedimentation rate and normal white blood cell count and liver enzymes. Chest radiography showed a moderate right pleural effusion and the ultrasound revealed a loculated effusion that was shown to be an eosinophilic exudate.ConclusionsThe temporal relationship between methimazole intake and the development of pleural effusion combined with the extensive exclusion of alternative causes, namely infectious, neoplastic and primary auto-immune diseases, led to the diagnosis of hypersensitivity reaction to methimazole. The thionamide was stopped and corticosteroid was started with complete resolution of the pleural effusion in 3 months.Awareness of this rare adverse reaction of anti-thyroid drugs is important and methimazole can be added to the list of possible etiologies of drug-induced eosinophilic pleural effusion.

Carbimazole-induced eosinophilic pleural effusion

“…There is one case report in the literature describing a pleural effusion as a result of methimazole 7. In this case, pleural aspiration did demonstrate an eosinophilic exudate; however, unlike our case, there was no peripheral eosinophilia.…”

“…There have been cases of vasculitis secondary to thionamides reported, with most caused by PTU. More rarely carbimazole and methimazole have been implicated 7. Drug-induced lupus has also been described 7–10.…”

Methimazole-Induced Pleural Effusion in the Setting of Graves’ Disease

“…This may be explained in the context that the methimazole led to ANCA associated vasculitis leading to pleural effusion. This differs from the Gaspar-da-Costa et al's (BMC) case, which had eosinophilic exudative effusion with likely hypersensitivity immune drug reaction, and ANCA negative work-up [3]. The Sen et al's case showed a neutrophilic predominant effusion, but there is no mention of ANCA being tested.…”

“…This is the third published case of methimazole related pleural effusion [2, 3]. In our case, the unilateral pleural effusion was initially managed in the setting of atrial fibrillation with rapid ventricular rhythm.…”

“…There are reported cases of methimazole-induced pulmonary hemorrhage; however, other complications such as pleural effusion are very rare with methimazole [2–4]. There have been two reported cases of methimazole associated pleural effusions [2, 3]. We report a case of methimazole-induced recurrent pleural effusion in a woman with Graves' Disease.…”