Carbimazole induced pleural effusion: a case report

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

Methimazole is a thionamide drug that inhibits the synthesis of thyroid hormones by blocking the oxidation of iodine in the thyroid gland. We report a case of methimazole-induced recurrent pleural effusion. A 67-year-old female with recently diagnosed Graves' disease on methimazole 20mg daily was admitted with dyspnea and new onset atrial fibrillation with rapid ventricular rate. Chest X-ray revealed a unilateral right pleural effusion, which was consistent with a transudate on thoracocentesis. She was managed as a case of congestive heart failure and methimazole dose was increased to 30 mg daily. She was readmitted twice with recurrent right pleural effusion. The fluid revealed an exudative process on repeat thoracocentesis. CT scan of the chest with contrast showed mediastinal lymphadenopathy and a diffuse ground glass process involving the right lower lobe suggestive of pneumonitis. Bronchoalveolar lavage showed neutrophil predominant fluid, and cytology and adenosine deaminase were negative. Patient also had an endobronchial ultrasound guided biopsy of the lymph nodes (EBUS). She was treated empirically with steroids 40 mg for 10 days and the methimazole was also discontinued. The antinuclear antibodies (ANA) came back positive with a speckled pattern; antineutrophil cytoplasmic antibody (c-ANCA) and antimyeloperoxidase were also positive. The effusion resolved but recurred on rechallenge with methimazole. She was referred for urgent thyroidectomy. The patient's repeat chest X-ray showed complete resolution of the pleural effusion after stopping the methimazole. Few weeks later, repeat ANCA and antimyeloperoxidase antibody were both negative. Our case report highlights the importance of the recognition of a rare side effect of methimazole. Timely diagnosis would ensure that appropriate treatment is given.

Carbimazole-induced eosinophilic pleural effusion

We report the case of a 41-year-old woman who presented with a unilateral exudative effusion with prominent eosinophils on pleural cytology. Carbimazole had been started 4 weeks prior to presentation. No immediate cause was identified on imaging or laboratory testing. The effusion persisted at 2-month follow-up. Further investigation at this time, including autoimmune serology was negative. At 2-month follow-up, the effusion was loculated on ultrasound imaging and had a low fluid pH on diagnostic aspiration, in keeping with an empyema. The patient received treatment for pleural empyema, including antibiotics, intercostal drain insertion and video-assisted thoracoscopic pleural biopsy. Carbimazole was stopped, and following treatment for the empyema, the effusion did not reaccumulate.This case illustrates the diagnostic difficulties that pleural effusions may present. It demonstrates that drug reactions should be considered in the differential diagnosis following thorough investigation for other potential causes and also describes the complications that may occur.

Methimazole associated eosinophilic pleural effusion: a case report

Background

Adverse 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 presentation

We 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.

Conclusions

The 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 exudative pleural effusions

Carbimazole, an antithyroid drug, is associated with a significant number of side effects, but pleuropulmonary complications are rare. We report the case of a 42-year-old Caucasian man who developed dyspnoea secondary to bilateral exudative pleural effusions while on carbimazole therapy. Extensive investigations, including a vasculitic screen, ruled out other potential causes for this patient's clinical presentation. This patient's pleural effusions gradually resolved within a few months of stopping carbimazole therapy, suggesting a role for the latter in the aetiopathogenesis of his presentation. Clinicians should consider discontinuing treatment with carbimazole and introducing alternative antithyroid therapy in this setting, once other potential causes of a pleural effusion have been systematically ruled out.