Thyroid emergencies
Thyroid storm or crisis is a life-threatening condition characterized by an exaggeration of the manifestations of thyrotoxicosis. When thyroid storm was first described, the acute mortality rate was nearly 100%. Today, the prognosis is significantly improved if appropriate therapy is initiated early; however, the mortality rate continues to be approximately 20%.
2. How do patients develop thyroid storm?
Thyroid storm usually occurs in patients who have unrecognized or inadequately treated thyrotoxicosis and a superimposed precipitating event, such as thyroid surgery, nonthyroid surgery, infection, or trauma.
3. What are the clinical manifestations of thyroid storm?
Fever (> 102° F) is the cardinal manifestation. Tachycardia is usually present, and tachypnea is common, but the blood pressure is variable. Cardiac arrhythmias, congestive heart failure, and ischemic heart symptoms may develop. Nausea, vomiting, diarrhea, and abdominal pain are frequent features (Fig. 38-1). Central nervous system manifestations include hyperkinesis, psychosis, and coma. A goiter is a helpful finding but is not always present.
Figure 38-1. Symptoms of thyroid storm.
4. What laboratory abnormalities are seen in thyroid storm?
Serum thyroxine (total T4 and free T4) and triiodothyronine (total T3 and free T3) are usually significantly elevated, and serum thyroid-stimulating hormone (TSH) is undetectable. These hormone levels, however, cannot reliably distinguish patients with thyroid storm from those who have uncomplicated thyrotoxicosis. Other common findings include anemia, leukocytosis, hyperglycemia, azotemia, hypercalcemia, and elevated liver enzymes.
5. How is the diagnosis of thyroid storm made?
The diagnosis must be made on the basis of suspicious but nonspecific clinical findings. If the diagnosis is strongly suspected, waiting for the results of tests may cause a critical delay in the initiation of effective lifesaving therapy. Clinical features are therefore the key. Table 38-1 provides a useful scoring system to aid in diagnosis.
6. What other conditions may mimic thyroid storm?
7. How should patients with thyroid storm be treated?
The immediate goals are to decrease thyroid hormone synthesis, to inhibit thyroid hormone release, to reduce the heart rate, to support the circulation, and to treat the precipitating condition. Because beta1-adrenergic receptors are significantly increased in patients with this condition, beta1-selective blockers are the preferred agents for heart rate control.
8. What drugs are used to decrease thyroid hormone synthesis?
Propylthiouracil, 600 to 1200 mg daily (oral, rectal, or nasogastric [NG] tube)
Methimazole, 60 to 120 mg daily (oral, rectal, NG tube, or intravenous [IV])
9. List drugs used to inhibit thyroid hormone release
Sodium iodide (NaI), 1 g over 24 hours (IV)
10. What drugs are used to reduce the heart rate?
