Hyperthyroidism
(Overactive Thyroid Gland)
What is hyperthyroidism?
A normal thyroid gland produces a hormone called thyroxine. A
normal blood level of thyroxine is required to maintain good
health. Hyperthyroidism leads to an increase in blood level
of thyroxine leading to ill health.
How common is this condition?
About 2 in 100 women, and 2 in 1000 men, develop hyperthyroidism
at some stage in their life.
What leads to an overactive thyroid?
The commonest form of overactive thyroid is caused by an inflammation
of the gland (Graves’ disease), the precise reason for
which is not clearly understood. It can occur in several members
of the same family.
What are the common symptoms of hyperthyroidism?
-
Patients may have several of the following symptoms:
swelling in the front of the neck, weight loss, feeling warm,
excessive sweating, irritability, difficulty in sleeping,
diarrhoea and palpitation.
-
Eye symptoms
in the form of bulging eyes, watering, grittiness, double vision
and painful eye movements can occur.
-
Women may have disturbances
in menstrual cycle and difficulty in conceiving.
-
Some patients may have very few symptoms and the
condition may be detected during routine blood tests.
How is the diagnosis confirmed?
Diagnosis is made by a simple blood test which shows a rise in
the level of the thyroid hormone.
How is this condition managed?
Hyperthyroidism usually requires treatment. If left untreated,
in certain patients it can lead to irregular heart rhythm and
thinning of bones over a period of time. There are 3 ways of
managing this condition:
Medical treatment:
-
This involves taking tablets
of Carbimazole or Propylthiouracil. After the initial 6-8 weeks
of this treatment thyroxine tablets may be added.
-
Blood tests
are required during treatment to adjust the dose of medications.
-
Medical treatment is usually withdrawn after 6-8
months although this period may vary. After stopping the tablets,
blood tests are required 2-3 times during the first year and
thereafter annually or during recurrence of symptoms.
-
In some patients who develop recurrence of the condition
on stopping the treatment, long term use of these tablets may
be necessary if radioiodine or surgery are not appropriate.
What are the side effects of the tablets?
Both agents are safe and are well tolerated. Minor side effects
include joint pains, nausea and skin rashes although the latter
can be more severe and may require withdrawal of treatment.
A major side effect of these drugs is a reduction in the number
of white cells of the blood. Although rare (1 patient in 5000),
this can be serious if not detected early and the instructions
below need to be followed.
If you develop a severe sore throat, fever or mouth ulcers while
being on either Carbimazole or Propylthiouracil, you should immediately
discontinue the medication and go to your General Practitioner
for a blood test. If the blood test is abnormal you should not
restart Carbimazole or Propylthiouracil and follow your General
Practitioner’s advice. If the blood test is normal you
should promptly restart the medication without waiting for the
above symptoms to clear up.
Surgery:
Thyroid surgery involves the removal of the whole or part of
the thyroid gland. It is recommended for patients who have recurrence(s)
of hyperthyroidism and are not suitable for long-term tablets
or radioiodine therapy. The operation is performed by specialist
surgeons and complications are uncommon which would be discussed
by your surgeon in greater detail.
Patients who undergo removal of the whole of the thyroid gland
require lifelong thyroxine tablets.
Which of the three forms of treatment would be best suited to
me?
The choice of treatment depends on a variety of medical factors
and on your choice. Medical therapy is the preferred option for
a majority of patients who experience this condition for the
first time. For those patients who relapse after withdrawal of
medical therapy (half of all patients) radioiodine or thyroid
surgery is usually recommended although long-term medical treatment
can also be considered.
What are the implications of this condition for pregnancy?
Both the condition itself and its treatment may have an impact
on pregnancy. Once having been diagnosed to have this condition
it is considered safe to be pregnant only when:
-
the condition is cured and treatment is withdrawn, or
the condition is controlled on small doses of medication
(less than 20mg Carbimazole).
-
more than 6 months have passed since successful radioiodine
therapy (and the resulting underactive thyroid condition has
been controlled).
-
Surgical treatment has cured the condition (and the resulting
underactive thyroid condition has been controlled).
What is the likely outcome (prognosis) of this condition?
With appropriate treatment the prognosis is good. Treatment may
lead to an underactive thyroid which is easy to treat with
lifelong thyroxine tablets.
What follow up care is required?
Once the condition is cured, 6-12 monthly blood tests should
be undertaken to assess the thyroxine balance. If you are in
the child bearing period and are on thyroxine tablets you should
increase the dose by 50mcg as soon as you are aware that you
are pregnant. Please get in touch with your General Practitioner
as well.
If you have any concerns or questions once you have read this
leaflet you can speak to your doctor at your next hospital appointment.
For more information you can visit:
www.british-thyroid-association.org
Our contact details:
Diabetes Centre
New Cross Hospital
Wolverhampton
WV10 0QP
Telephone no: 01902 695310 |
