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
Exam |
Tests |
Results |
Actions |
Initial
patient visit |
Medical
history |
History
of exposure only with normal examination and screening
tests |
Educate
patient on early warning signs of thyroid and parathyroid
diseases. |
|
|
|
|
Physical
exam with thyroid gland palpation |
Thyroid
nodule
found (1 cm or larger) |
Begin
screening workup. Schedule next visit. |
|
Serum
thyroid stimulating hormone (TSH) level |
TSH
or serum free thyroxine (FT4) abnormalities |
Obtain
levels of serum calcium, parathyroid hormone (PTH), FT4,
and antithyroid peroxidase antibodies. |
|
|
|
Refer
patient to an endocrinologist, as appropriate. |
|
|
Abnormal
serum calcium level |
Redraw
blood; if abnormal, test for PTH and refer to endocrinologist
as appropriate. |
|
|
Abnormal
antithyroid peroxidase antibody level |
Schedule
repeat exam in 1 year with palpation and thyroid function
tests. Refer patient to an endocrinologist, as appropriate. |
|
|
Normal
antithyroid peroxidase antibody level |
|
|
|
|
|
|
|
|
|
Follow-up
visit for a patient with a palpable thyroid nodule |
Follow
medical protocol for ultrasound and FNAB |
Normal
or benign |
Schedule
next visit. See Figure 2. |
|
|
Abnormal
or nondiagnostic |
Schedule
for evaluation by surgeon. |
|
During
future physical examinations |
Medical
history update |
|
|
|
Serum
TSH and calcium levels |
Normal
examination and tests |
Educate
patient on early warning signs of thyroid and parathyroid
diseases. |
|
|
Abnormal
examination or tests |
Schedule
for evaluation by surgeon. |
|
Physical
Exam with thyroid palpation |
Thyroid
nodule found (1 cm or larger) |
Begin
screening workup. Schedule next visit. |
The
frequency of examinations will depend on the presence
of any thyroid abnormalities. For patients who have no
abnormalities identified initially, no periodic visits
are necessary but TSH should be tested when a physical
is performed. For patients with abnormalities, the provider
should schedule examinations at yearly intervals. |
|
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
11. How can you find
out if potassium iodide (KI) is available to your community in
case of an emergency?
For a printer-friendly
version of the Radiation Exposure From Iodine 131 case study,
download the PDF version.
You need to have
Adobe Acrobat Reader to download a PDF version. Click here to
go to the Adobe Web site,
and follow the instructions to install this free software on your
computer.
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