Hyperthyroidism is 10 times more common in women. Insufficiency of TH is referred to as hypothyroidism,

 

Hyperthyroidism is 10 times more common in women.

Insufficiency of TH is referred to as hypothyroidism,

and 95% of the time it is caused by dysfunction of the

thyroid gland. One of the more common causes of hypothyroidism is Hashimoto thyroiditis, an autoimmune

condition in which the body produces antibodies to the

TSH receptor, which block signaling, and does not allow

production of TH. Other causes include iodine deficiency,

infiltrative diseases affecting the thyroid gland, or administration of drugs ( eg, arniodarone). At its extreme, hypothyroidism can manifest as myxedema coma, a severe and

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THYROID EMERGENCIES

life-threatening state that occurs more frequently in the

elderly.

CLINICAL PRESENTATION

� History

Depending on the degree of abnormality, patients will

present with varied severity of symptoms. Patients with

earlier stages of thyrotoxicosis will report excessive sweating, weight loss, palpitations, anxiety, and heat intolerance.

Patients in thyroid storm will present with symptoms of

thyrotoxicosis in addition to fever, tachycardia, altered

mental status, and often congestive heart failure. In elderly

patients, there is a rare form of thyrotoxicosis referred to as

apathetic hyperthyroidism, presenting with lethargy,

altered mental status, blepharoptosis (drooping of the

upper eye lid), weight loss, and atrial fibrillation leading to

congestive heart failure.

On the opposite side of the spectrum, patients with hypothyroidism complain of fatigue, depression, weight gain, cold

intolerance, and dry skin. In its severe state, myxedema coma,

patients present with altered mental status, bradycardia,

hypothermia, hypoventilation, and hypotension.

Both thyroid storm and myxedema coma usually occur

in patients with previously diagnosed thyroid disorders

and are usually precipitated by other factors, such as

infection, trauma, diabetic ketoacidosis, stroke, surgery, or

medication noncompliance.

� Physical Examination

Clinical findings in both hyper- and hypothyroidism are

summarized in Table 68-1. Not all the signs and symptoms

will be present in every patient. Frequent findings in

patients with hyperthyroidism owing to Graves disease

include goiter, exopthalmos, palmar erythema, and tachycardia (Figure 68-1). In thyroid storm, in addition to those

findings, patients will have altered mental status, fever,

hypertension, and frequently atrial fibrillation.

Hypothyroid patients will present with fatigue, periorbital

edema, hair loss, and dry skin. Myxedema coma patients

will have altered mental status, hypothermia, hypotension,

and myxedema (non-pitting peripherial edema owing to

the accumulation of mucopolysaccharides in the skin).

DIAGNOSTIC STUDIES

� Laboratory

It is important to note that both thyroid storm and myxedema coma are clinical diagnoses and are not defined by

absolute levels of hormones. The main test used for

assessment of thyroid function is ISH level, and its use as

a single test is appropriate for an initial evaluation of thyroid function. In patients with an intact hypothalamicpituitary-thyroid axis, small changes in the level of TH

will lead to significant changes in ISH levels. In a majority

of cases, normal ISH effectively excludes dysfunction of

Table 68-1. Comparison of clinical presentation

of patients with hyper- and hypothyroidism.

System Hyperthyroid Hypothyroid

Vital signs Tachycardia Bradycardia

Hypertension Hypotension

Fever Hypothermia

General Weight loss Weight gain

Hyperkinesis Fatigue/lethargy

Anxiety Depressed

HEENT Goiter Periorbital edema

Exophthalmos Loss of outer third of

Lid lag* the eyebrows

Hoarse voice

Hair loss

Cardiovascular Arrhythmias (atrial Bradycardia

fibril lation)

Widened pulse pressure

Lungs Dyspnea ± pleural effusion

Abdomen Diarrhea Constipation

Skin Warm Cool

Moist Dry

Palmar erythema Rough skin

Nonpitting edema

Neuro Altered mental status Altered mental status

Hyperreflexia Memory impairment

Delayed deep tendon

reflexes**

Note: The degree of symptoms depends on severity of disease.