methimazole and Anemia--Sideroblastic

The authors describe a 62 year-old white male who was diagnosed as autoimmune hyperthyroidism and treated with methimazole and atenolol. Ten days later he showed itching, jaundice and choluria. All drugs were discontinued. The patient was given radioactive iodine. Two months later direct serum bilirubin levels reached 35 mg%. Endoscopic retrograde cholangiogram evidenced normal extrahepatic biliary ducts. The percutaneous liver biopsy showed marked cholestasis specially in the centrolobular zone with a slight infiltrate of mononuclear cells in the portal areas. Together with the liver disease the patient presented an anemic syndrome. Bone marrow aspiration showed rich cellularity, Perls staining showed 70% sideroblasts, with 10% ringed sideroblasts and increased extracorpuscular iron. The patient's evolution was satisfactory. Twenty months after the beginning of the disease clinical and biochemical tests were normal. A new bone marrow aspiration rendered normal. Hepatic cholestasis suffered by our patient was probably due to an adverse reaction of methimazole. Physiopathology of reversible sideroblastic anemia is discussed.

Topics: Anemia, Sideroblastic; Atenolol; Cholestasis, Intrahepatic; Humans; Hyperthyroidism; Liver Function Tests; Male; Methimazole; Middle Aged; Thyroid Function Tests