In the setting of characteristic features of thyrotoxicosis, the timely diagnosis and aggressive management of thyroid storm should result in a successful outcome. However, severe storm may lead to irreversible cardiovascular collapse, especially in the older patient who may have atypical features of thyrotoxicosis. The fundamental approach is prompt and optimal treatment in the emergency department once the presenting clinical features suggest its presence. Delay in the introduction of therapy while awaiting laboratory confirmation may result in further decompensation and death. The prevention of myxedema coma entails paying special attention to certain high-risk patient groups. These groups include older women with a history of Hashimoto's thyroiditis, or previous irradiation or thyroid surgery for hyperthyroidism. Inform such patients of the symptoms and signs of hypothyroidism, and perform annual thyroid function tests, such as a serum TSH, in order to provide early, adequate treatment once the test becomes positive.