Agency for Toxic Substances and Disease Registry
Radiation Exposure from Iodine 131
Treatment and Management

Initial and Follow-Up Visits for Patients Identified as Exposed to I-131

The major clinical concerns after significant I-131 exposure, especially in infants and children who are more susceptible than adults, include developing hypothyroidism and thyroid cancer. Currently, children who are born in the United States are screened at birth for thyroid function; therefore, no thyroid tests are necessary for children growing normally without other medical problems, unless they are exposed to significant doses of I-131.

Table 1. Summary of Initial and Follow-Up Visits for Patients Identified as Exposed to I-131 in Previous Years

If a nodule is benign, the patient could be treated with T4 in a dose sufficient to suppress serum TSH, which will limit glandular growth. If the nodule decreases in size, the patient should be maintained on T4 indefinitely and the nodule monitored with palpation and ultrasound. If the nodule persists while the patient is on T4 therapy, a repeat FNAB is necessary. If the nodule grows during T4 therapy, surgical resection is indicated.

Distant metastasis is uncommon, but lung and bone are the most common sites. In the case of thyroid cancer that has metastasized to other organs, it is helpful to have additional pathology analysis to determine whether the cancer is a thyroid cancer or whether it originated from another organ. This is particularly important in the case of former nuclear workers who might be eligible for compensation only for cancer originating from certain organs, or for nonworkers who are seeking compensation through the legal system for exposure health outcomes.

Approach to the Patient and Family

• Most people affected by I-131 exposure are psychologically healthy, functioning adults who are experiencing high levels of stress.
• Accurate information on the possible health effects of I-131 is needed after exposures due to nuclear releases.

To work effectively with patients, physicians need to understand that people who have been exposed to radiation are having normal, typical emotional responses that are to be expected under the circumstances. After any exposure, it is important that the psychologic support for the patient be combined with a risk communication plan to provide accurate information about the acute and delayed health effects of I-131. This will give exposed persons some of the information they need to understand the event. To ensure that information is accurately and completely understood, it may need to be repeated over a period of days or weeks. Distribution of clearly written information, with references to the scientific literature, might also be useful. Provision of timely and correct information is one key to preventing stress and relieving psychosocial effects after notification of the potential health risks of I-131 exposure.

Persons exposed to I-131, as well as family members of those exposed, need an opportunity to ask questions of health experts about the potential risk for present or future effects. Psychologic support should be continued after the immediate event because fear of possible future health effects can persist and might contribute to psychologic illness.

Distress versus Disease

Most people will suffer normal emotional distress; only a few will develop psychologic illnesses depending on the circumstances of their exposure. Specific psychotherapeutic or psychopharmacologic treatments might also be useful to treat posttraumatic stress disorders, anxiety disorders, or depression that might occur in some patients in the aftermath of exposure. However, if depression occurs in a patient exposed to I-131, it is important to differentiate organically based mood changes possibly related to hypothyroidism from psychologically based depression related to stress about the exposure. Depression is a disorder, but can be a symptom. Symptoms similar to depression, such as a sad mood, lethargy, and lack of appetite, can be caused by an underlying hypothyroid condition, which must be diagnosed and treated correctly and not mistaken for depression. Consultations between endocrinologists and psychiatrists are recommended for these complex situations.

Challenge Question

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