OBJECTIVETo analyze the causes of misdiagnosis of primary hypothyroidism (PH), with an attempt to reduce the misdiagnosis or mistreatment.

METHODSTotally 70 PH children with a history of misdiagnosis but whose conditions were confirmed in Peking Union Medical College Hospital and the First Hospital of Jilin University from July 2000 to May 2009 were enrolled in this study. The clinical data were collected and the causes of misdiagnoses were analyzed.

RESULTSOf these 70 patients, 19 were misdiagnosed as anaemia and dystrophy, 18 as pituitary tumors, 10 as adiposities, 6 as myocarditis or pericardial effusion, 4 as Downs syndrome, 3 as hepatitis, 3 as amyasthenia, 3 as cerebral palsy, 2 as cystis thyrolingualis, and 2 as congenital megacolon. The duration of misdiagnoses ranged from 6 to 72 months. The clinical manifestations of these patients were complicated, involving multiple organs and systems.

CONCLUSIONSPH has complicated clinical manifestations and individual variations, and therefore can be easily misdiagnosed. Good knowledge, sufficient history-taking, and cautious physical examinations can help avoid misdiagnosis. Neonatal screening is helpful for diagnosis and treatment of congenital hypothyroidism.