Patient Education - Endocrine Encyclopedia
Endocrine Surgery Encyclopedia
Definition:
A thyroid nodule is a growth (lump) in the thyroid gland. The thyroid gland is located
at the base of the neck.
Alternative Names: Thyroid adenoma; thyroid carcinoma; thyroid incidentaloma
Causes, incidence, and risk factors:
Thyroid nodules are growths of cells in the thyroid glands. These growths can be
benign (non-cancerous) or malignant (cancerous). Some nodules are fluid-filled (cysts),
while others are completely made of thyroid gland cells. Sometimes, what feels like
one nodule will actually be a collection of small nodules close together.
Thyroid nodules that are big enough to feel during a physical exam occur in 5
- 7% of the population. Smaller nodules occur in as many as 50% of people aged 60
or older. Thyroid nodules are more common in women than in men. A person's chance
of a thyroid nodule increases with age.
Only 4 - 5% of thyroid nodules are cancerous. (See: Thyroid Cancer)
The following characteristics increase the risk for a cancerous nodule:
- Family history of medullary thyroid carcinoma
- Family history of multiple endocrine neoplasia Type II
- A hard nodule
- A nodule that is stuck to nearby structures
- Vocal cord paralysis
- Other risk factors for a cancerous nodule include:
- Male gender
- Age -- younger than 20 years or older than 70
- History of radiation exposure to the head or neck
Causes of thyroid nodules are not always found, but can include:
- Iodine deficiency
- Suppression of thyroid hormone
- Hashimoto's disease
Symptoms:
Most thyroid nodules produce no symptoms.
Large nodules can press against other structures in the neck. Symptoms may include:
- Difficulty breathing
- Difficulty swallowing
- Hoarseness or changing voice
- Pain in the neck
- Goiter
Nodules that produce thyroid hormones will cause symptoms of hyperthyroidism, including:
- Weight loss
- Increased appetite
- Nervousness
- Restlessness
- Clammy skin
- Skin blushing or flushing
- Bounding pulse
Thyroid nodules resulting from Hashimoto's disease may cause symptoms of hypothyroidism,
including:
- Intolerance to cold
- Fatigue
- Dry skin
- Hair loss
- Unintentional weight gain
- Facial swelling
Signs and tests:
Very often, doctors will find thyroid nodules only during a routine physical exam,
because the nodules produce no symptoms. When a doctor finds a nodule, or when there
are symptoms that suggest a nodule, your doctor may order the following tests:
- TSH level
- Fine needle aspiration biopsy
- Thyroid ultrasound
- Thyroid Scan -- a nodule that works apart from the thyroid gland is said to
be "warm" or "hot," and
will appear darker on the scan. Only 1% of working nodules are cancerous. Approximately
20% of cold (non-working) nodules are cancerous.
- T3 and T4 levels
Treatment:
Some thyroid nodules disappear without treatment. Surgery is recommended for nodules
that:
- Are cancerous
- Cause symptoms
- Cannot be diagnosed as cancer or non-cancer
Patients with working nodules sometimes receive treatment with radioactive iodine,
which reduces the size of the nodule. However, the treatment can cause hypothyroidism
and radiation-induced thyroiditis (inflammation of the thyroid gland). Pregnant women
should not be given this treatment. Women being treated with radioactive iodine should
not get pregnant.
Levothyroxine (Synthroid, Levoxyl, Levothroid, Unithroid) is a drug that suppress
the production of the thyroid hormone T4. A doctor may prescribe levothyroxine to
treat benign nodules only in special cases, including:
- A growing nodule
- A nodule causing pressure on other structures in the neck
- When many nodules are growing in the thyroid gland
Levothyroxine does not seem to benefit most people with thyroid nodules, and can
cause serious complications. Complications include heart problems and loss of bone
density.
Careful follow-up is the only recommended treatment for benign nodules that do
not cause symptoms and are not growing. A thyroid biopsy may need to be repeated
6-12 months after diagnosis. An ultrasound may be repeated as well.
Newer treatments include ethanol (alcohol) injection into the nodule and laser
therapy.
Expectations (prognosis):
Non-cancerous thyroid nodules are not life threatening. Many do not require treatment,
only follow-up. Non-cancerous nodules that do require treatment have an excellent
outlook.
The outlook for cancerous nodules depends on the type of cancer. See Thyroid Cancer
for more information. Complications:
Hyperthyroidism is a common complication of non-cancerous thyroid nodules. Complications
of treatment can include:
- Nodule regrowth
- Scarring from surgery
- Hoarseness or voice changes as a result of vocal cord damage during surgery
-- this happens especially if the nodule is close to the voice box
- Heart-related problems as a result of side effects from medication
- Weak bones resulting from medication treatment
- Hypothyroidism
Calling your health care provider:
Call your health care provider if you feel
or see a lump in your neck, or if you experience any symptoms of a thyroid nodule.
Prevention:
The reason for most thyroid nodules is unknown. A diet with enough
iodine will help prevent some nodules.
References:
Sriram U, Patacsil LM. Thyroid Nodule. Dis Mon 2004; 50(9):486-526.
Hegedus L. The Thyroid Nodule. N Eng J Med 2004;351:1764-71.
Goldman L, Ausiello D. Cecil Textbook of Medicine, 22nd ed. Philadelphia, Pa:
WB Saunders; 2004.
Rakel RE. Textbook of Family Practice. 6th ed. Philadelphia, Pa: WB Saunders;
2005.
Review Date: 5/11/2006
Reviewed By: Rita Nanda, M.D., Department of Medicine, Section of Hematology/Oncology,
University of Chicago Medical Center, Chicago, IL. Review provided by VeriMed Healthcare
Network.
 A.D.A.M.,
Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission
(www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M.
follows rigorous standards of quality and accountability. A.D.A.M. is among the first to
achieve this important distinction for online health information and services. Learn more
about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also
a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net
Foundation (www.hon.ch).
The information provided herein should not be used during any medical emergency or for
the diagnosis or treatment of any medical condition. A licensed medical professional should
be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for
all medical emergencies. Links to other sites are provided for information only -- they do
not constitute endorsements of those other sites. © 1997- 2007 A.D.A.M., Inc. Any duplication
or distribution of the information contained herein is strictly prohibited.
|
