Treatment of Graves' Disease Associated With Severe Neutropenia

Severe neutropenia in newly diagnosed hyperthyroidism is a diagnostic and therapeutic dilemma since antithyroid drugs (ATDs) cannot be started if the absolute neutrophil count (ANC) is <1 x 10⁹/L. We report the case of a patient followed for hyperthyroidism associated with severe neutropenia treated with dexamethasone and ATD. The patient was 51 years old and was hospitalized for hyperthyroidism with a thyroid stimulating hormone (TSH) level <0.005 (0.4-4) mUI/L, T4 at 415 (9.3-17.1) ng/L and T3 at 148 (2-4.4) pg/mL on Graves' disease (GD) confirmed by the TSH receptor antibodies at 38 IU/mL and scintigraphy, associated with neutropenia, with ANC at 0.4 x 10⁹/L. He was put on prednisolone 60 mg/day and propranolol 60 mg/day for three weeks without improvement. Faced with the association of hyperthyroidism and severe neutropenia, we could not start the ATD for fear of agranulocytosis; we put the patient on propranolol 60 mg and dexamethasone 6 mg with progressive degression resulting in a spectacular increase of ANC from 0.4 x 10⁹/L to 7.1 x 10⁹/L, which allowed us to start the ATD (carbimazole) at a dose of 30 mg, and then 50 mg, with monitoring of ANC and transaminases every 48 hours. Euthyroidism was achieved after 15 days. A curative treatment with radioactive iodine ablation was administered. Our patient did not respond to prednisolone but responded dramatically to dexamethasone; this leads us to consider using dexamethasone for the rapid preparation for radical treatment of patients with GD.