Hashimoto’s Thyroiditis
Symptoms
Cause
Diagnosis
Treatment
Hashimoto’s thyroiditis (also called autoimmune
or chronic lymphocytic thyroiditis) is the most common thyroid
disease in the United States. It is an inherited condition
that affects approximately 14 million Americans. It is about
7 times more common in women than in men.
Hashimoto’s thyroiditis is characterized by the production
of immune cells and autoantibodies by the body’s immune
system, which can damage thyroid cells and compromise their ability
to make thyroid hormone. Hypothyroidism occurs if the amount
of thyroid hormone which can be produced is not enough for the
body’s needs. The thyroid gland may also enlarge in some
patients, forming a goiter.
Symptoms
Many patients with Hashimoto’s thyroiditis may have
not symptoms for many years, and the diagnosis is made incidentally
when an enlarged thyroid gland or abnormal blood tests are
discovered as part of a routine examination. When symptoms
do develop, they are either related to local pressure effects
in the neck caused by the goiter itself, or to the low levels
of thyroid hormone. The first sign of this disease may be painless
swelling in the lower front of the neck. This enlargement may
eventually become easily visible and may be associated with
an uncomfortable pressure sensation in the lower neck. Left
untreated, a person may begin to have trouble swallowing or
even breathing.
Although many of the symptoms associated with thyroid hormone
deficiency occur commonly in patients without thyroid disease,
patients with Hashimoto’s thyroiditis who develop hypothyroidism
are more likely to experience the following:
- Fatigue
- Drowsiness
- Forgetfulness
- Difficulty with learning
- Dry, brittle hair and nails
- Dry, itchy skin
- Puffy face
- Constipation
- Sore muscles
- Weight gain
- Heavy menstrual flow
- Increased frequency of miscarriages
- Increased sensitivity to many medications
The thyroid enlargement and/or hypothyroidism caused by Hashimoto’s
thyroiditis tends to progress in many patients, causing a slow
worsening of symptoms. Therefore, patients with either of these
findings should be recognized and adequately treated with thyroid
hormone. Optimal treatment with thyroid hormone will eliminate
any symptoms due to thyroid hormone deficiency, usually prevent
further thyroid enlargement, and may sometimes cause shrinkage
of an enlarged thyroid gland.
What is the cause of Hashimoto’s thyroiditis?
Hashimoto’s thyroiditis results from a malfunction
in the immune system. When working properly, the immune system
is designed to protect the body against invaders, such as bacteria,
viruses, and other foreign substances. The immune system of
someone with Hashimoto’s thyroiditis mistakenly recognizes
normal thyroid cells as foreign tissue, and it produces antibodies
that may destroy these cells. Although various environmental
factors have been studied, none have been positively proven
to be the cause of Hashimoto’s thyroiditis.
Diagnosis
The physicians of Endocrine Associates of West Michigan and
Thyroid Specialists of Michigan are experienced in the diagnosis
and treatment of thyroid disease. They can detect a goiter
caused by Hashimoto’s thyroiditis by performing a physical
examination, and can recognize hypothyroidism by identifying
characteristic symptoms, finding typical physical signs, and
doing appropriate laboratory tests.
Antithyroid antibodies
Increased antithyroid antibodies
provide the most specific laboratory evidence of Hashimoto’s
thyroiditis, but they are not present in all cases.
TSH (thyroid-stimulating hormone or thyrotropin) test
Increased
TSH level in the blood is the most accurate indicator of hypothyroidism.
TSH is produced by another gland, the pituitary, which is located
in the center of the head behind the nose. The level of TSH rises
dramatically when the thyroid gland even slightly underproduces
thyroid hormone, so a normal level of TSH reliably excludes hypothyroidism
in patients with normal pituitary function.
Other tests
Free T4 (thyroxine) – the active
thyroid hormone in the blood. A low level of free T4 is consistent
with thyroid hormone deficiency. However, free T4 values in
the “normal
range” may actually represent thyroid hormone deficiency
in a particular patient, since a high level of TSH stimulation
may keep the free T4 levels “within normal limits” for
many years.
Fine-needle aspiration of the thyroid – usually not
necessary for most patients with Hashimoto’s thyroiditis,
but a good way to diagnose difficult cases and a necessary
procedure if a thyroid nodule is also present.
Treatment
For patients with thyroid enlargement (goiter) or
hypothyroidism, thyroid hormone therapy is clearly needed,
since proper dosage corrects any symptoms due to thyroid hormone
deficiency and may decrease the goiter’s size. Treatment
consists of taking a single daily tablet of levothyroxine.
Older patients who may have underlying heart disease are usually
started on a low dose and gradually increased, while younger
healthy patients can be started on full replacement doses at
once.
Thyroid hormone acts very slowly in the body, so it may take
several months after treatment is started to notice improvements
in symptoms or goiter shrinkage. Because of the generally permanent
and often progressive nature of Hashimoto’s thyroiditis,
it is usually necessary to treat it throughout one’s
lifetime and to realize that medicine dose requirements may
have to be adjusted from time to time.
Appropriate management of Hashimoto’s thyroiditis requires
continued care by a physician who is experienced in the treatment
of this disease. |
