|ACTH ||Adrenocorticotropic hormone |
|ADH ||Antidiuretic hormone (vasopressin) |
|APACHE ||Acute physiology and chronic health evaluation |
|CT ||Computed tomography |
|DDAVP ||1-deamino-8-D arginine vasopressin |
|DKA ||Diabetic ketoacidosis |
|FT4 ||Free thyroxine |
|GFR ||Glomerular filtration rate |
|IL ||Interleukin |
|L-T4 ||Levothyroxine |
|MRI ||Magnetic resonance imaging |
|PTH ||Parathyroid hormone |
|PTHrP ||Parathyroid hormone–related protein |
|SIADH ||Syndrome of inappropriate antidiuretic hormone secretion |
|T3 ||Triiodothyronine |
|TPP ||Thyrotoxic periodic paralysis |
|TSH ||Thyroid-stimulating hormone |
Acute or chronic failure of an endocrine gland can occasionally result in catastrophic illness and even death. Thus, it is important to recognize and appropriately manage these endocrine emergencies. This chapter will discuss crises involving the thyroid, anterior pituitary, or adrenal glands; diabetes mellitus; and abnormalities in calcium, sodium, and water balance. Except where indicated, management recommendations are provided for adult patients. Studies in the general area of endocrine emergencies have been limited in size and number. In many instances, recommendations offered in this chapter are based on published expert opinion rather than scientific evidence.
Myxedema coma is the end stage of untreated or inadequately treated hypothyroidism. It has an estimated incidence of 0.22 per million per year. The clinical picture is often that of an elderly obese female, presenting in midwinter with increased lethargy, somnolence, and confusion. The presentation is one of severe hypothyroidism, with or without coma (the term myxedema coma may, therefore, be a misnomer). The history from the patient may be inadequate, but the family may report that the patient has had thyroid surgery or radioiodine treatment in the past or that the patient has previously been receiving thyroid hormone therapy. Myxedema coma is most frequently associated with discontinuation of thyroid hormone therapy. It presents less frequently as the first manifestation of hypothyroidism. It may be precipitated by an illness such as a cerebrovascular accident, myocardial infarction, or an infection such as a urinary tract infection or pneumonia. Other precipitating factors include gastrointestinal hemorrhage; acute trauma; excessive hydration; or administration of a sedative, narcotic, or potent diuretic drug.
The physical findings are not specific. The patient may be semicomatose or comatose with dry, coarse skin, hoarse voice, thin scalp and eyebrow hair, possibly a scar on the neck, and slow reflex relaxation time. There is marked hypothermia, with body temperature sometimes falling to as low as 24°C (75°F), particularly in the winter months. It is important to be alert to the presence of complicating factors such as pneumonia, urinary tract infection, ileus, anemia, hypoglycemia, or seizures. Fever may be masked by coexistent hypothermia. Often there are pericardial, pleural, or peritoneal effusions. The key laboratory tests are a low free thyroxine (FT4) and elevated thyroid-stimulating hormone (TSH). The TSH elevation may be less than predicted due to the presence of euthyroid sick syndrome ...