Graves' disease is an autoimmune disorder that
can affect the thyroid, the eyes and the skin.
It is the most common cause of
hyperthyroidism in the United States.
Stimulation of autonomous production of T4 and
T3 is through antibodies against TSH receptors.
These receptors can be checked
in the serum as a TSI
or thyroid stimulating immunoglobulin
or thyroid releasing antibody.
A positive family history is
always a frequent accompaniment.
A new diagnosis of Graves' disease, one would start
by checking thyroid stimulating immunoglobulins
which are there to stimulate TSH
receptors present on the thyroid gland
which in turn increase the activity of the gland with
consequent increased production of thyroid hormones,
usually T4 and occassionally T3.
Thyroid function test reveal the classic
features of low TSH, high T4 and/or T3.
Let's go through some of the clinical
signs of Graves' disease.
Patients may have an elevated
blood pressure on physical exam
and may also have a widening
of their pulse pressure.
A widening of the pulse pressure manifests
when the systolic blood pressure
is much higher than the diastolic blood pressure.
This is the hallmark of thyroid hormone effect
on the heart where increased cardiac output
and increased pumping of the myocardium
occurs, thus widening the pulse pressure.
Patients also manifest clinically with tachycardias.
These tachycardias may
be regular or irregular.
If they're irregular, they're
called atrial fibrillation.
There's also a diffusely enlarged thyroid
and occassionally, a thyroid bruit
which is the abnormal sound that the
blood vessels of the thyroid make
as blood flows through them rapidly.
Patients may also manifest pretibial myxedema
which we'll describe in subsequent slides
And they have the characteristic eye signs.
These eye signs can include
lid retraction or lid lag,
proptosis which look like bulging
of the eye in the orbit,
scleral injection where the
sclera of the eye appears red
and finally, periorbital edema with
the entire orbit seems to be swollen
In the right image, you see many of the
features of classic dysthyroid eye disease.
The diagnosis of Graves' disease
is made clinically in most cases.
The first lab to check off the TSH and free T4
would be the thryoid stimulating antibodies
Radio active iodine uptake and scan will show increased
uptake with diffuse activity on the scan image.
The treatment of Graves' disease is a stepwise
approach, usually starting with thioanamide drugs,
followed by beta blockers to control heart rate.
If the thyrotoxicosis recurs or if there are
any compressive symptoms of the thyroid gland,
surgery is considered.
In the absence of a response to medications, one can
also consider radioactive iodine ablation therapy.
Thionamide drugs can be used
consecutively for up to two years.
Methimazole, one of the first line agents
has a higher intrathyroid retention rate
and therefore is more effective.
Typically, once-daily dosing also
makes this drug quite convenient
and it has a reduced side effect profile.
One important thing to be aware
of is a first trimester teratogen
causing a condition called
aplasia cutis in the fetus.
This should be taken into account
especially when prescribing methimazole
to women of reproductive age.
Another drug is called propylthiouracil or PTU
which has limitations based on its side effects.
It can increase aminotransferase
levels and affect the liver
and in very rare cases lead
to fatal hepatotoxicity.
Second line treatment for Graves' disease
includes radioactive iodine ablation
which will, in most cases, render
the patient completely hypothyroid.
As a consequence, they then would
require lifelong thyroid replacement.
Finally, surgery is considered in patients in
whom control cannot be achieved with drugs
and who are not comfortable
with radioiodine therapy.
Other lab pattern of thyroid
disease worth mentioning.
When you see an elevated TSH with
an elevated T4 and/or T3,
consider the rare condition
of secondary hyperthyroidism
that is caused by TSH-secreting
Where the TSH is low plus a normal
free T4 but an elevated T3,
this is the condition we described
earlier known as T3 toxicosis.
And then finally if the TSH is
low with a normal T4 and T3,
consider the condition of
Typical causes of which include pregnancy
and other non-thyroidal illness.