Goiter

Make the Diagnosis: Goiter

Prior Probability

The prior probability of a goiter is affected by many variables, including the patient's body surface area, sex, and regional variations associated with the endemic iodine deficiency. Two recent European studies of thyroid volume among community samples of healthy adults give us insight into the prevalence of goiter in the non–iodine-deficient area: 4% of patients in Spain (95% confidence interval [CI], 3%-6%)⁸ and 10% of patients in France (95% CI, 9%-11%)⁹ had palpable goiters. Unfortunately, the thyroid volume was not confirmed for patients with palpable goiters. Nonetheless, we can make some inferences that give us good starting points. The WHO defines an iodine-deficient area by the prevalence of goiter in school-aged children. According to normative population values, children who live in a non–iodine-deficient area should have a goiter prevalence of less than 5%.¹ Adults might have palpable thyroid glands for reasons other than iodine deficiency, so prevalence values slightly higher make sense. A starting point of 5% to 10% for healthy adults makes sense for the prior probability of a palpable thyroid.

Population for Whom a Goiter Disease Should Be Considered

• Symptoms of hyperthyroidism or hypothyroidism

• Children, especially those in endemic iodine deficiency locales

• Pregnant and lactating women

• Elderly patients

• Patients with excessive radiation exposure

• Patients with Down syndrome

Detecting the Likelihood of a Goiter

Because examining children is different from examining pregnant women for thyroid disease, we cannot combine the data (see Table 21-10). The techniques for examination, however, are similar. We have no data for the results of thyroid palpation in non-pregnant adults because epidemiologic studies of normal adults’ thyroid volume exclude those with palpable enlargement.

Palpating thyroid tissue in both lobes of a volume greater than the volume of the patient's distal thumb phalanx increases the likelihood of a goiter, but there will be false-positive results.

Reference Standard Tests

Ultrasonography.

In epidemiologic research, urinary iodine studies are evaluated along with thyroid palpation.

Original Article: Does This Patient Have a Goiter?

Clinical Scenarios

How Large Are These Thyroid Glands?

For each of the following patients, assessment of thyroid size is an important part of the clinical examination. In case 1, a 32-year-old ...