Hyperthyroidism Signs Symptoms Causes Treatment Medication
Posted By HealthcareOnTime Team
Posted on 2021-07-13
What is Hyperthyroidism?
Thyroid normally has a self-control mechanism, which is also known as "feed
back mechanism". However, sometimes this control mechanism fails and the
production of the hormones is more than the requirement. This clinical
condition is called hyperthyroidism. The excess of thyroid hormones result in
certain signs and symptoms of increased metabolic activity. In such patients, the
levels of FT3 and FT4 are above normal values and the TSH levels drop (exactly
opposite to hypothyroidism).
Causes of Hyperthyroidism
All patients with Hypothyroidism may not have the same cause, but majority
have an unnatural stimulus by a TSH like substance, which is an antibody against
TSH receptor on the thyroid. Such stimulation may be in the entire thyroid gland
or in part of it. The increased output of the hormones from the thyroid produces
some or all of the symptoms associated with hyperthyroidism. Grave's disease
What causes sudden hyperthyroidism?
An autoimmune disorder is the most common cause of
hyperthyroidism. Instead of TSH, antibodies against the
TSH receptors, bind to and stimulate the thyroid gland, leading to
continuous and uncontrolled production of thyroid
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Signs and symptoms of Hyperthyroidism
Increased bowel movement
Scanty menstrual periods or
Increased heart rate
Warm and moist skin
Hyperthyroidism and Thyrotoxicosis: Are they same?
No. When blood thyroid hormone
levels are in excess, either due to a
drug (e.g. excess of Thyroxine
supplements) or disease (Thyroiditis)
or hyperthyroidism, such condition is
called as thyrotoxicosis. Thus, thyro-
toxicosis is a term which defines
higher levels of thyroid hormones be
whatever the cause; whereas hyperthyroidism refers to over functioning
of the thyroid gland. This knowledge
is essential because a patient with
thyrotoxicosis but without hyperthyroidism should not be treated
for the latter.
Hyperthyroidism and Thyroiditis: Are they related?
Thyroiditis is an inflammation of the
thyroid gland due to autoimmunity,
which partially or completely des-
troys the functioning of the gland.
During the phase of active inflammation, thyroid cells are destroyed and
hence release the stored thyroid
hormones (triiodothyronine (T3) and T4). The T3 and T4 (thyroxine)
levels may remain raised for days or
months. This elevation in the
hormone levels can be confused and
misdiagnosed as hyperthyroidism. It
is essential to rule out thyroiditis in all
patients with thyrotoxicosis with the
help of laboratory tests before starting
any specific therapy.
Since thyroiditis is an autoimmune
disorder, the patient will have
circulating antibodies, mainly against
the thyroid specific protein, thyroglobulin (anti-thyroglobulin antibodies
or ATG) and microsomal antigen
(anti-microsomal antibodies or AMA).
AMA are also known as anti-thyroid peroxidase antibodies. Though it is
not confirmatory, the presence of both
these antibodies in the patient's blood
can alert the physician to be cautious
before instituting therapy for hyperthyroidism.
Thyroid uptake test using radioiodine
or another suitable radioisotope has to
be done. High levels of uptake by the
gland indicate hyperthyroidism and
treatment for this condition should
Treatment modalities for hyperthyroidism
1. Drug therapy
2. Radioiodine therapy
Either one or a combination of the above three
modalities are given, as treatment for patients with
hyperthyroidism. Each of these has its own
advantage and limitation, with individual
physicians preferring one to the other, due to
reasons of simplicity, cost and availability and also
considering severity of hyperthyroidism, existing
illness and the patient's age. The symptoms of
hyperthyroidism may be rapidly relieved by betablockers. These medications counteract the
increased metabolic effect of thyroid hormones,
without altering their levels.
Anti-Thyroid Drugs (ATDs)
Anti-Thyroid Drugs block the production of thyroid hormones
and are used to bring back thyronormalcy. These
drugs include thioamides like Propylthiouracil
(PTU) or Neomercazole or Methimazole which are
believed to be immunomodulatory also. PTU is
preferred in pregnant hyperthyroid patients. For
majority of Thyroidologists, ATDs are the first
choice of therapy due to their availability and one
can stop medication at any time desired. The dose
and duration of Anti-Thyroid Drugs is based on the age and
severity of hyperactivity and the cause of hyperthyroidism.
What is Radioiodine therapy
Not all cases of hyperthyroidism are easily controlled by ATDs and
here radioiodine therapy becomes a better choice. Iodine-131 is a
radioactive isotope of iodine. Because of its isotopic nature, it is
unstable as an atom and releases gamma and beta rays. These when
come in contact with cells, cause reactions within and destroy it. The
degree of destruction depends on the amount of radioisotope given.
Small amounts destroy lesser amount of cells. The body can recover
the loss of cells to a certain extent. Large quantities of radioisotope
are required for the treatment of thyroid cancer as they are useful to
destroy cancer cells .
In radiolodine therapy, depending upon the extent of thyroid gland
destruction, the amount of the same is administered. For
hyperthyroidism where one is interested in partial destruction of the
gland, smaller doses such as 5-10mCi is given. It is like doing a
surgery and removing a part of the gland without cutting open the
patient and avoiding anesthesia.
In case of thyroid cancer, where the whole thyroid has to be
destroyed, radioiodine in larger doses of more than 50mCi are given
along with surgery. This helps in complete removal of cancerous
cells which may have been left behind after surgery.
Radioiodine therapy is simple and also cheap. However, since only
nuclear medicine professionals do the handling, non-nuclear
medicine thyroidologists give less importance to radioiodine
treatment. There is a misconception in the minds of the patients and
many physicians that radioiodine treatment is very harmful.
Radioiodine is contraindicated in pregnancy and during
Where radioiodine treatment is not available and the patient does
not respond to ATDs, a partial thyroidectomy may be an option.
However, thyroid surgery is done under general anesthesia and the
surgery is costly. If along with hyperthyroidism, the patient has a
solitary or multinodular goiter, surgery is preferred. This mode of
treatment requires 5 to 7 days of hospitalisation.
Every patient will need proper evaluation before selecting treatment.
No treatment mode can be said to be the best for every patient of
hyperthyroidism. Since physicians have their individual
preferences, all the three are widely used. Many thyroidologists are
of the opinion that, if available, radioiodine is the best.
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Management & monitoring of hyperthyroidism in patients
Every patient may not respond well to ATDs and a decision
has to be made for alternate treatment, keeping in mind what
is ideal for the patient, its cost and availability. And hence the
management of hyperthyroidism is crucial. The conventional
laboratory tests T3, T4 and TSH often yield results that are
difficult to comprehend. In these patients, since the intact
hypothalamus pituitary thyroid axis is disturbed, it requires
expertise to fine tune the dosage to avoid either unwanted
therapy or under treatment. Many thyroidologists use TSH,
FT3 and FT4 combinations to get a correct picture of the
The conditions can be analysed by evaluating the levels of
thyroid hormones. Once diagnosed, these abnormal
conditions can be brought to perfect normalcy with the help
of proper medication within few weeks or months.