Although thyroid-related medical conditions are relatively common in the general population, the acute life-threatening thyroid emergency rarely presents. Both hyper- and hypothyroidism can contribute to the etiology of a number of critical ED presentations, ranging from acute psychosis to frank coma. With reported mortality rates ranging from 20% to 80% for the life-threatening, decompensated forms of hypo- and hyperthyroidism, myxedema and thyroid storm, respectively, it remains crucial that the emergency clinician be versed in their diagnosis and treatment.1,2
This issue of Emergency Medicine Practice reviews the fundamental principles of the management of thyroid emergencies using a focused, evidence-based approach to the literature. Although thyroid disorders constitute a wide-ranging clinical spectrum, this review will focus on the common final pathway of acutely decompensated hyper- and hypothyroidism, myxedema, and thyroid storm. Accurate diagnosis and the application of proven emergent treatments are critical in reducing the profound mortality rates related to both conditions.
Case #1: A 65-year-old woman is brought to the emergency department (ED) with altered level of consciousness and hypotension. Her neighbor found her on the kitchen floor. He checked on her because he hadn't seen her for 3 days. The patient is unable to provide any verbal history. Her vital signs are respiratory rate of 10 respirations per min, blood pressure of 90/60 mm Hg, temperature 35°C (95°F), and heart rate 50 beats per min. On physical examination, you see an obtunded woman in no apparent distress. You note a well-healed surgical scar on her anterior neck and that her left leg is shortened and externally rotated. The differential diagnosis of the presentation is long and complex, and you keep wondering if that scar on the neck has a bearing on her management.
Case #2: A 50-year-old man presents with complaints of a fever and "feeling anxious." The patient has had a productive cough, subjective fever, and myalgias for 7 days. Yesterday, he began to "feel anxious" and like his "heart was racing." His pas medical history is significant for a goiter that is still being evaluated. His vital signs are respiratory rate of 18 respirations per min, blood pressure of 160/80 mm Hg, temperature 38°C (100.4°F), and heart rate 140 beats per min. On physical examination, you note that the patient appears nontoxic. He has a tender goiter, a fine tremor of his hands, and an irregular heart rhythm. On his lung examination, there are left midfield rales. You suspect community-acquired pneumonia, but the tender goiter introduces management concerns.
We performed a literature review through Ovid MEDLINE and PubMed using the terms hyperthyroidism, thyrotoxicosis, thyroid storm, hypothyroidism, and myxedema. We then performed a manual search of the resulting articles to find further relevant articles. The Endocrine Society has published an excellent clinical management guideline for hyperthyroidism and hypothyroidism as well as for the pregnant and postpartum population, but this does not address emergent intervention.3 Recent meta-analyses and randomized control trials tend to focus on the ideal pharmacological, radiotherapeutic, or surgical regimens for long-term therapy of hyperthyroidism, all of which are of limited importance to the emergency clinician. A number of case reports and case reviews exist as well for the more esoteric presentations associated with thyroid disorders.
Aside from the relatively recent development of intravenous thyroxine, the management of myxedema and thyroid storm has changed little since the mid twentieth century. Perhaps the most relevant papers to the practicing emergency clinician are the focused clinical reviews available on subtopics within the thyroid disease literature, including neonates, children, the elderly, antithyroid drugs, and mechanical ventilation principles.
Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.
To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study, will be included in bold type following the reference, where available. In addition, the most informative references cited in this paper, as determined by the authors, will be noted by an asterisk (*) next to the number of the reference.