3. INTRODUCTION
What is thyrotoxicosis?
• Thyrotoxicosis is the name given to
the clinical effects experienced due
to an excess of thyroid hormones in
the bloodstream. Hormones
produced by the thyroid gland
control how fast or slow the body
works (metabolic rate). Too much
thyroid hormone (thyroxine and
triiodothyronine) speeds up the
metabolism and results in the signs
and symptoms of thyrotoxicosis
What causes thyrotoxicosis?
The main cause of thyrotoxicosis is
hyperthyroidism, which is an
overactivity of the thyroid gland
resulting in it producing excess
levels of thyroid hormones. If the
hyperthyroidism is due to an
autoimmune cause, it is called
Graves' disease.
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4. INTRODUCTION
• Other rarer causes of thyrotoxicosis include excessive intake of
thyroid hormone in patients treated for hypothyroidism (an
underactive thyroid gland) and sometimes, inflammation of the
thyroid gland (thyroiditis), which causes release of large quantities of
thyroid hormone into the bloodstream. Other conditions that may
cause excessive thyroid hormone production include toxic
multinodular goitre and toxic thyroid adenoma (the term ‘toxic’ refers
to over-production of thyroid hormones). Certain medications, for
example, amiodarone and lithium, can also cause excessive thyroid
hormone production.
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5. Is thyrotoxicosis the same as
hyperthyroidism?
• Hyperthyroidism is a type of thyrotoxicosis. Hyperthyroidism happens
specifically when your thyroid gland both produces and releases
excess thyroid hormone. Hyperthyroidism is often called overactive
thyroid. Thyrotoxicosis happens when you have too much thyroid
hormone in your body in general.
• You could have too much thyroid hormone from taking too much
thyroid medication, for example. This would be thyrotoxicosis, not
hyperthyroidism
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6. EPIDIMOLOGY
• Thyroid disease tends to be commoner in women than men (up to 10
times more). Thyrotoxicosis can occur at any age and there is a 1 in 100
chance of a woman developing it in her lifetime and a 1 in 1,000 risk for
men. The number of new cases diagnosed each year is 3 per 1,000
women.
• Thyrotoxicosis is a common disorder, especially in women.
• Thyrotoxicosis is relatively rare. It happens to approximately 2% of
females and 0.2% of males.
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7. RISK FACTOR & ETIOLOGY
• The most frequent cause is Graves' disease (autoimmune
hyperthyroidism).
• Hyperthyroidism: Hyperthyroidism, which happens when your thyroid
makes and releases too much thyroid hormone, is the most common
cause of thyrotoxicosis. Graves’ disease, an autoimmune disease, is
the most common cause of hyperthyroidism. It represents 80% of
hyperthyroidism cases. Having one or more nodules on your thyroid
can also cause hyperthyroidism and thyrotoxicosis.
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8. CONTD..
• Thyroid inflammation (thyroiditis): Thyroid inflammation (swelling) can be
caused by certain bacterial and fungal infections, immune system issues and
certain drugs such as lithium and interferon. The inflammation causes your
thyroid to leak stored, or preformed, thyroid hormone, resulting in higher
levels of hormones than your body needs. Thyroiditis can also happen after
having a baby (postpartum thyroiditis).
• Excess thyroid medication: Consuming excess thyroid medication can cause
thyrotoxicosis. This can happen if you have hypothyroidism (underactive
thyroid) and take too much of your thyroid medication, whether accidentally
or intentionally. If you have thyroid cancer, your healthcare providers may
intentionally give you excess thyroid medication to try to suppress the amount
of thyroid-stimulating hormone (TSH) in your body to try to prevent or
decrease the growth of your thyroid tumor.
• Consuming too much thyroid hormone: You can also have too much thyroid
hormone in your body by consuming beef that’s contaminated with thyroid
tissue from the cow’s neck. This is often called “hamburger thyroiditis,” and
it’s a very rare cause of thyrotoxicosis.
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9. contd...
• Thyrotoxicosis can have many causes; determining the cause is
essential to formulate a treatment plan
• A radioactive iodine uptake and scan should be performed when the
cause of a patient's thyrotoxicosis cannot be definitively determined
by history and physical examination
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10. DIAGNOSIS
• Symptoms of thyrotoxicosis are generally the same in mild and
moderate cases, but they're usually more intense the more severe the
thyrotoxicosis is.
• If pathognomonic signs are present (diffuse goiter with orbitopathy,
dermopathy, or acropachy), no further testing is required to establish
the diagnosis.
• In the absence of these signs, measurement of TSH receptor
antibodies (TRAbs) (97% sensitivity and 98%-99% specificity for GD)24
can be helpful, especially in the setting of a nodular goiter.25 Normal
or increased radioactive iodine (RAI) uptake (RAIU) with diffuse
distribution on the scan can also confirm the diagnosis and
distinguishes GD from other causes of thyrotoxicosis
• . More recently, color flow Doppler sonography (CFDS) with thyroid
ultrasound has been employed with good accuracy for GD diagnosis
as well (sensitivity of 87% and specificity of 100%)
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11. Signs and symptoms of mild and moderate
thyrotoxicosis include:
Experiencing unexplained weight loss.
• Having an irregular heartbeat (arrhythmia).
• Having a rapid heartbeat (tachycardia) — usually a heart rate higher than
100 beats per minute.
• Experiencing muscle weakness.
• Feeling shaky.
• Feeling nervous, anxious and/or irritable.
• Experiencing increased sensitivity to heat.
• Experiencing changes in your menstruation (period).
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12. severe case of thyrotoxicosis
• A severe case of thyrotoxicosis is called thyroid storm, or thyroid crisis.
This condition is rare and requires immediate medical attention, as it
can be life-threatening.
• Symptoms of thyroid storm (severe thyrotoxicosis) include:
• Having a very rapid heartbeat.
• Having a high fever.
• Feeling very agitated and confused.
• Having diarrhea and feeling sick.
• Experiencing a loss of consciousness
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13. What tests will be done to diagnose this
condition?
• A physical exam.
• Blood tests.
• Imaging tests.
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14. TESTS
• Physical exam
• If you’re experiencing symptoms of thyrotoxicosis, during a physical exam in your
healthcare provider’s office they may physically check the following:
• Your thyroid: Your provider may gently feel your thyroid through the outside of
your neck to check if it’s enlarged, bumpy or tender.
• Your eyes: Your provider may check your eyes for swelling, redness, bulging and
other signs of thyrotoxicosis.
• Your heart: Your provider may use a stethoscope to listen to your heart for a rapid
heartbeat and irregular heartbeats.
• Your hands: Your provider may have you outstretch your hands to see if you have a
tremor.
• Your skin: Your provider may feel your skin to see if it’s warm and moist.
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15. Blood tests
• Your healthcare provider may take a blood sample to look for high
levels of thyroid hormones. This is called thyroid function testing.
When you have thyrotoxicosis, your levels of the thyroid hormones
triiodothyronine (T3) and thyroxine (T4) are higher than usual and
thyroid-stimulating hormone (TSH), a hormone your pituitary gland
makes, is lower than it should be. The level of TSH in your blood is
important because it signals your thyroid gland to produce thyroxine.
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16. Imaging tests
• Taking a closer look at your thyroid can help your provider diagnose
thyrotoxicosis and the possible cause of it. Imaging tests your
provider could use to examine your thyroid include:
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17. Treatment options for thyrotoxicosis include:
• Anti-thyroid drugs: Anti-thyroid drugs such as methimazole (Tapazole) and
propylthiouracil (PTU) block your thyroid from making hormones. People who
have hyperthyroidism may take this medication.
• Radioactive iodine: If you have hyperthyroidism you may take radioactive
iodine by mouth. Your overactive thyroid cells absorb the radioactive iodine,
which damages the cells. This causes your thyroid to shrink and your thyroid
hormone levels to go down. This usually leads to permanent destruction of your
thyroid, which then causes hypothyroidism. Because of this, most people who
receive this treatment have to take thyroid hormone drugs for the rest of their
lives to maintain appropriate hormone levels.
• Surgery: Your healthcare provider may recommend removing your thyroid
gland through surgery (thyroidectomy). This will correct your hyperthyroidism,
but it will usually cause hypothyroidism. People who have a thyroidectomy have
to take thyroid hormone drugs for the rest of their lives to maintain appropriate
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18. contd...
• Beta blockers: These drugs block the action of thyroid hormones on
your body. They don’t change the level of hormones in your blood,
but they can help control symptoms, such as rapid heartbeat and
shakiness, that are caused by thyrotoxicosis. If you have thyroiditis,
your healthcare provider may recommend beta blockers until your
thyroiditis goes away. If you have a chronic condition that causes
hyperthyroidism, your provider may prescribe beta blockers in
addition to another treatment to treat your hyperthyroidism over the
long term.
• Glucocorticoids: Glucocorticoids are a type of corticosteroid. If you
have thyroiditis that’s causing you pain, your provider may prescribe
you glucocorticoids.
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19. Medication
• carbimazole or another called propylthiouracil is used. These act
on enzymes in the thyroid gland to prevent production of thyroid
hormones.
• Patients can be treated using
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20. DESIRED OUTCOME
• The management of GD is 2-fold:
• symptom control and
• treatment of the underlying hyperthyroi dism.
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21. • Most of the symptoms are due to overstimulation of β-adrenergic
receptors. β-Blockade, therefore, is the mainstay of symptom control.
Nonselective propranolol offers the additional benefit of decreasing
the peripheral conversion of T4 to T3.
• In a thyroid storm, glucocorticoids are also used for this purpose.
• Radioactive iodine ablation, antithyroid drugs (ATDs), and
thyroidectomy are the mainstay treatment options for the underlying
hyperthyroidism (Table 2). Radioactive iodine has been the preferred
first-line approach in the United States (unlike Europe, where ATDs
are favored)34; however, its use has been decreasing.35, 36
Interestingly, quality of life after treatment is no different regardless
of treatment modality.
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22. • Radioactive iodine – this involves the patient taking either a capsule
of radioactive iodine. This is carried out as an outpatient. Iodine is
taken up by the thyroid gland so that the radioiodine is concentrated
in the gland and causes a gradual destruction of the overactive gland.
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23. 1. Antithyriod drugs:
DRUG Dose:
Propylthiouracil: 100 to 150 mg every 8 hours,
Methimazole: 15 to 60 mg divided every 12
hours depending on severity
of illness.
• Inhibit the oxidation of
iodine and coupling of
iodotyrosines, thus
decrease the synthesis of
thyroid hormone. PTU in
addition decreases the
conversion of T4 to T3 in
peripheral tissues
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24. • Although blockade of hormones synthesis is rapid,
clinical improvement occurs after few weeks or
months, because a large pool of stored hormone
continues to be released from thyroid.
• The patient becomes euthyroid 2 to 3 months after
beginning therapy.
Propylthiouracil may achieve results faster because it
prevents the peripheral conversion
of T4 to active T3.
• After clinical improvement, the dose of the
medication is tapered to the lowest dose to
maintain euthyroid state and the drug is continued for 1
- 1 ½ yrs.
• A free T4 level should be checked after 1 month of
therapy and then every 2 to 3 months.
• Side effects /drug toxicity
• Skin rash or joint pain
• Agranulocytosis
• Advantages of Atithyroid drugs:
• Hospitalization , surgery and anesthesia
are avoided
• The occurrence of post treatment
hypothyroidism is less likely
• Disadvantages:
• • Permanent remission occurs in fewer
than 50 % of patients
• • Treatment success depends on patient
compliance to treatment
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