Hypothyroidism - Complications

Highlights	Symptoms	Medications
Introduction	Complications	Resources
Causes	Diagnosis	References
Risk Factors	Treatment

Diagnosis

Doctors diagnose hypothyroidism after completing a medical history and physical exam of the patient and performing laboratory tests on the patient's blood. Because symptoms of hypothyroidism can mimic those of many other conditions, blood tests for measuring levels of thyroid stimulating hormone (TSH) and free thyroxine (T4) are the only definitive way to diagnose hypothyroidism. However, the results of these blood tests can be affected by illnesses that are not thyroid related.

Physical Examination

The doctor will check the heart, eyes, hair, skin, and reflexes for signs of hypothyroidism.

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Goiter. The presence of a goiter (an enlarged thyroid), especially a rubbery, painless one, may be an indication of Hashimoto's disease. If the thyroid is tender and enlarged but not necessarily symmetrical, the doctor may suspect subacute thyroiditis. A diffusely enlarged gland may occur in hereditary hypothyroidism, in postpartum patients, or from use of iodine or lithium. Goiters may also develop in people with iodine deficiency.

Thyroid Hormone and Antibody Tests

In diagnosing hypothyroidism, blood tests measuring thyroid hormone levels are needed to make a correct diagnosis. In some cases, antibody tests are also helpful.

Thyroxine (T4). Hypothyroidism is a condition marked by low thyroxine (T4) hormone levels, and a test can measure levels of this hormone in the blood. However, this test is usually inadequate for the following reasons:

T4 levels can be normal early in the disease process leading to hypothyroidism. If hypothyroidism is suspected, other tests are needed.
T4 levels can be low in patients who do not have hypothyroidism. For instance, thyroxine can be extremely variable in very elderly or seriously ill patients and during pregnancy.

Measurements of thyroxine may be accompanied by a process called a T3 resin uptake, which corrects for the presence of medications (such as birth control pills, aspirin, and others) that could distort the T4 results. Other tests are needed to confirm a diagnosis of hypothyroidism.