Postinfectious Guillain-Barre syndrome in a patient with methimazole-induced agranulocytosis
A 57-year-old female presented with fever, abdominal pain, and diarrhea for 3 days. She had been diagnosed with Graves disease 25 years prior and was taking methimazole, the dose of which had been increased from 5 to 20 mg twice a day, as of 10 weeks prior. When the patient visited a primary care hospital, her laboratory findings revealed leukopenia and anemia with a white blood cell (WBC) count of 570/mL, absolute neutrophil count of 10/mL, hemoglobin of 9.4 g/dL, and platelet count of 161,000/mL. The physician diagnosed her with methimazole-induced agranulocytosis and stopped methimazole.\nDuring the neutropenic period, the patient developed fever and cough. The pathogen of infection was not confirmed, and she took empirical antibiotics for pneumonia. Clinical features were not improved, and the physician considered fungal pneumonia based on the findings of chest computed tomography. Ten days after onset of respiratory symptoms, she suddenly presented with symmetric weakness of the lower extremities, which progressed to the upper extremities. A nerve conduction study (NCS) showed axonal-type motor polyneuropathy. Intravenous immunoglobulin (IVIg) was started for probable GBS, and she was referred to our hospital for further management.\nWhen the patient first came to our emergency room, a neurologic examination showed quadriplegia, flaccid dysarthria, and aflexia, all of which were worse than 5 days before. The findings of spinal tap were 218.9 mg/dL protein and 10/mL WBC in the cerebral spinal fluid, known as albuminocytologic dissociation, which supported GBS. She was treated with IVIg (0.4 g/kg/day) for 5 days. The patient showed maximum weakness during the first 2 weeks after admission to the intensive care unit, but artificial ventilation was not needed. Neurologic examination and follow-up NCS improved a month after the onset of weakness ().\nAs methimazole treatment was discontinued, thyrotoxicosis was aggravated. The patient faced an impending thyrotoxic crisis with free thyroxine of 6.59 ng/dL (reference range, 0.89 to 1.8), thyroid-stimulating hormone (TSH) of 0.01 mIU/mL (reference range, 0.35 to 5.5), and TSH receptor antibody of 107 IU/L (reference range, 0.1 to 1.0). Lugol's solution and lithium were prescribed to reduce thyroid hormone production and secretion. A total thyroidectomy was performed three weeks later ().\nThe patient had been admitted for 40 days and received physical rehabilitation. With gradual neurologic improvement, she could ambulate using a wheelchair when discharged. After discharge, she maintained rehabilitation therapy for 6 months. The patient could walk without orthotics; however, she felt fatigue after a long distance walk.