The symptoms of
hyperthyroidism are numerous.
They include heat intolerance, palpitations,
dyspnea or shortness of breath, tremulousness,
menstrual irregularities and increase
in the frequency of stool and diarrhea,
weight loss and increased appetite.
In the rest of the body there may
be proximal muscle weakness,
patients may manifest fatigue
and difficulty sleeping.
They may also have mood
disturbances and be very irritable.
In all the patients, the classic
symptoms tend to be absent.
However, cardiac manifestations
are much more prominent.
Patients may present with abnormal
heart rates or atrial fibrillation
and may eventually develop heart failure.
The patterns of abnormal thyroid
function tests are as follows:
The initial evaluation is always based
on the clinical signs and symptoms.
Check her TSH alone initially to gauge
whether the patient is hyper or hypothyroid.
In the setting of suppressed TSH, then
go on and check her T4 and T3 level.
The typical pattern of
hyperthyroidism seen in this case
is a low TSH and an elevated
T4 and/or elevated T3.
This is the hallmark of
A word on terminology.
Thyroid hormone excess from different sources.
First of all, endogenous thyroid
disorders will cause thyrotoxicosis
which is the clinical syndrome
of thyroid hormone excess
manifesting with the
symptoms described above.
Pituitary tumors can also cause an increase
secretion of thyroid releasing hormone,
which again, will lead
to a hyperthyroid state.
This, however, is very very rare.
You can also have thyrotoxicosis
from taking exogenous levothyroxine.
So patients with a low thyroid who are
over medicating themselves with thyroxine
may manifest symptoms of thyrotoxicosis.
Hyperthyroidism is the more specific term
to describe thyroid gland overactivity.
The most common causes though, are
Graves' disease and toxic adenomas.