thyroid

Guest Speaker
Dr. Abhishek Agarwal M.D.
Family Medicine

• Butterfly shaped
gland in front of the
neck
• Uses iodine in the diet
to make thyroid
hormones T3 & T4
• Thyroid hormones
regulate body
metabolism

GRAVES DISEASE :
• Generalized overactivity of the thyroid gland
• Thyroid gland has lost the ability to to respond
to the normal control by pituitary gland via
TSH
• Autoimmune disease with antibodies directed
against the thyroid gland that make it produce
excess thyroid hormone

GRAVES DISEASE
• Triggers for graves disease :
1. Stress
2. Smoking
3. Radiation to neck
4. Viral infections
• Diagnosed by thyroid scan (diffuse uptake)
• Blood test show high TSI (thyroid stimulating
immunoglobulin) antibody level

GRAVES DISEASE
• May be associated
with eye disease
(ophthalmopathy).
Eyes protrude out and
double vision can
occur. Stroids needed
for treatment

FUNCTIONING ADENOMA & TOXIC
MULTINODULAR GOITER
• The gland gets lumps that do not produce any
excess hormone and require no treatment
• Occasionally one nodule gets “autonomus”
and starts producing thyroid hormone. If there
are many such nodules its called toxic MNG
• These are easily detected on thyroid scan

THYROIDITIS (inflammation of the gland)
• Fever, sore throat, pain with swallowing. The
gland is tender to touch
• Affects 8% of women after delivery. Self
limiting
• Initially patient gets hyperthyroid as the
inflamed gland releases too much hormone.
Later it gets hypothyroid

EXCESSIVE INTAKE OF IODINE
• Seen more in patients who already have an
underlying abnormal thyroid gland.
• Certain meds like amiodarone(Cordarone)
have high iodine content and can lead to this

EXCESSIVE INTAKE OF THYROID HORMONE
• Due to lack of f/u of patients taking thyroid
medicine
ABNORMAL SECRETION OF TSH
• Tumor in the pituitary – very rare

HASHIMOTO’S THYROIDITIS
• Most common cause of hypothyroidism in the
country
• The thyroid gland is enlarged and has a
decreased ability to produce thyroid hormone
• Autoimmune disease where the body has
antibodies that attack its own thyroid tissue!
• Has a genetic basis. Can run in families
• Blood tested for antibodies to enzyme TPO

HASHIMOTO’S THYROIDITIS
• 10 times more common in women
• Patient may have other autoimmune diseases
like diabetes type 1 or pernicious anemia (Vit.
B12 deficiency)
• Diagnosed by detecting anti-TPO antibodies in
blood and by thyroid scan

LYMPHOCYTIC THYROIDITIS FOLLOWING
HYPERTHYROIDISM
• When inflammation is due to lymphocyte
which is a particular type of white blood cell
• Common after pregnancy
• Hyperthyroid stage at start followed by a
hypothyroid phase that lasts about 6 months
after pregnancy and then gets better on its own

THYROID DESTRUCTION SECONDARY TO
RADIOACTIVE IODINE OR SURGERY
• Patients who have received radioactive iodine
therapy or surgery for treatment of
hyperthyroidism may be left with no
functioning thyroid tissue
• If there is no significant activity 6 months after
iodine treatment, it is assumed there will no
longer be adequate functioning thyroid. The
result is hyperthyroidism

PITUITARY OR HYPOTHALAMIC DISEASE
• If for some reason the pituitary or
hypothalamus cannot signal the thyroid to
produce the hormones hypothyroidism will
result. Its is called secondary and tertiary
hypothyroidism

MEDICATIONS
• Methimazole and PTU are meds for
hyperthyroidism and can actually cause
hypothyroidism
• Lithium used as a psychiatric medicine can
cause this as a side effect

• TSH (SCREENING
TOOL)
• T3
• T4
• ANTIBODIES :
1. Antithyroglobulin
Antibodies
2. Anti TPO Antibodies
3. TSH receptor
stimulating antibodies

ULTRASOUND :
1. If there is concern
about structure of the
gland
2. To quantify size
3. If there is suspicion of
cancer
4. Good to detect
calcification and cysts
5. Cannot tell benign
from cancerous gland

RADIOIODINE
SCANNING AND
UPTAKE
1. Radioactively labeled
form of iodine used
2. Thyroid is the only
tissue in the body that
takes up iodine
3. Very specific for
finding thyroid tissue

RADIOIODINE
SCANNING AND
UPTAKE
1. If thyroid is not picking
up iodine normally
“spots” show up
2. Cold spots are where
the tissue is not picking
up iodine (can be
cancerous)
3. Hot spots are where the
tissue is picking up too
much iodine (toxic
nodule)

Cold nodules
notorious for being
cancerous!

• Best technique to rule out cancer
• Performed in the doctor’s office and takes about 20
minutes
• Complications are rare, but include bleeding,
bruising and infection.
WHEN IS IT DONE?
1. To make a diagnosis of thyroid nodule
2. To help select therapy for thyroid nodule
3. To treat a thyroid cyst by draining its contents via
aspiration
4. To inject a medicine to shrink a recurrent cyst

HYPOTHYROIDISM :
• Usually requires
lifelong thyroid
hormone therapy
• Synthetic T4 is used in
the form of a pill to be
taken once daily in
morning 30 minutes
before food
• Avoid iron containing
meds and antacids with
it

HYPOTHYROIDISM :
• Started at a lower dose in patients with heart
disease and gradually dose is increased at 6
week intervals
• Therapy is monitored at 6 weeks intervals until
stable thyroid hormone levels are achieved.
During these visits a blood test for TSH level is
done (normal TSH 0.5-5.0 IU/ml)
• Once stable TSH can be checked annually

TREATING THE SYMPTOMS :
• Beta blockers immediately treat symptoms like
palpitations and increased heart rate.
• These meds do not affect the level of the
thyroid hormone in the blood and are simply
for symptomatic relief

ANTITHYROID DRUGS
• Methimazole and PTU : accumulate in thyroid
tissue and block hormone production
• As a serious side effect they can suppress the
production of white blood cells that fight
infection
• Impossible to know if and when this would
occur so regular testing of white blood cells is
not useful. If patient gets any signs of infection
the doctor needs to know immediately

ANTITHYROID DRUGS
• The patient is seen monthly by the doctor till
the thyroid level are stable and then every 3-6
months
• Long term antithyroid meds are used only for
patients with graves disease as it may go into
remission with these meds thereby avoiding
the radioactive iodine or surgery as treatment
• Data shows remission rates of 40-70%
• In remission the gland would not need
antithyroid meds

RADIOACTIVE IODINE THERAPY
• Radioactive iodine isotope-123 used orally as a
one time dose. Iodine being specific for thyroid
tissue ablates it.
• The radioactive iodine is picked up by the
active cells in the thyroid and destroys them
• Radioactive iodine ablation has been safely
used for over 50 years, and the only major
reasons for not using it are pregnancy and
breast feeding

RADIOACTIVE IODINE THERAPY
• Treatment of choice for recurring Graves'
disease, patients with severe cardiac
involvement, those with multinodular goiter or
toxic adenomas, and patients who cannot
tolerate antithyroid drugs
• If a woman chooses to become pregnant after
ablation, it is recommended she wait 8-12
months after treatment before conceiving

RADIOACTIVE IODINE THERAPY
• In general, more than 80% of patients are cured
with a single dose of radioactive iodine. It takes
between 8 to 12 weeks for the thyroid to become
normal after therapy
• Permanent hypothyroidism is the major
complication of this form of treatment. While a
temporary hypothyroid state may be seen up to six
months after treatment with radioactive iodine, if
it persists longer than six months, thyroid
replacement therapy (with T4 or T3) usually is
begun

SURGERY
• Surgery to partially remove the thyroid gland
(partial THYROIDECTOMY) was once a
common form of treatment for
hyperthyroidism
• If too much tissue is removed, hypothyroidism
may result. In this case, thyroid replacement
therapy is begun

SURGERY
• The major complication of surgery is disruption of
the surrounding tissue, including the nerves
supplying the vocal cords and the four tiny glands
in the neck that regulate calcium levels in the body
(the parathyroid glands). Accidental removal of
these glands may result in low calcium levels and
require calcium replacement therapy
• With the introduction of radioactive iodine
therapy and antithyroid drugs, surgery for
hyperthyroidism is not as common as it used to be