7. Thyrotoxicosis / Hyperthyroidism Flashcards
What is the difference between thyrotoxicosis and hyperthyroidism?
Thyrotoxicosis - This is when there is an excess of thyroid hormone in the blood (regardless of cause)
Hyperthyroidism - This is when there is an overproduction of thyroid hormone from the thyroid gland.
What is the difference between primary and secondary hyperthyroidism?
Primary is due to abnormal thyroid physiology
Secondary is due to abnormal hypothalamus / pituitary physiology
What is exophthalmos? What causes it? What does it indicate?
It is anterior bulging of the eyes out of the socket in Graves Disease. This is due to inflammation, swelling and hypertrophy of the tissue behind the eyeball
What is pretibial myxoedema? What condition is it indicative of?
Pretibial Myxoedema is a dermatological condition where there are deposits of mucin under the skin on the anterior aspect of the leg (the pretibial area). This gives a discoloured, waxy, oedematous appearance to the skin over this area. It is specific to Grave’s disease and is a reaction to the TSH receptor antibodies.
How do the lab test results for primary and secondary hyperthyroidism differ?
Primary - High Th4, High Th3 and Low TSH
Secondary - High Th4, High Th3 and Normal or High TSH
What are the causes of hyperthyroidism?
1) Graves Disease
2) Multinodular Goitre
3) Solitary Toxic Nodule
4) Thyroiditis
What is Graves Disease?
It is where the body produces antibodies that mimic TSH and stimulate the TSH receptors on the thyroid, causing hyperthyroidism.
How does Graves Disease lead to eye problems?
The antibodies that mimic TSH may also attack the ocular muscles , leading to both vision problems and exophthalmos
If someone says there eyes feel grainy, what condition are you thinking of?
Graves Disease
What is the risk with Graves Disease and pregnancy?
Even if you’ve had graves disease, and the treatment has brought you back down to normal levels of thyroid hormone, there is a risk that you still have graves antibodies in your blood, which can cause problems for the Fetus during or after pregnancy
What is the issue with graves disease and men specifically?
It can cause a marked reduction in sperm count, resulting in reduced fertility. The sperm count usually returns to normal once the thyroid condition has been treated.
What is multi nodular goitre?
This is a condition where the patient produces multiple thyroid nodules, which contain abnormal thyroid tissue so that the thyroid gland ends up producing more thyroid hormone than normal. They are independent of TSH regulation, so produce thyroid hormones at their own will. They are usually non-cancerous
What is Plummers Disease?
This is another name for multinodular goitre
How long does it take for a multinodular goitre to go away by itself?
It never does.
What are the causes of thyroiditis?
- De Quervain’s Thyroiditis
- Hashimoto’s Thyroiditis
- Postpartum thyroiditis
- Silent (painless) thyroiditis
- Drug-induced thyroiditis
- Radiation-induced thyroiditis
- Acute or infectious thyroiditis
What is De Quervain’s Thyroiditis?
This is caused by a viral infection, causing fever, neck pain, pysphagia and features of hyperthyroidism. There is a hyperthyroid phase followed by hypothyroid phase as the TSH level falls due to negative feedback.
How is De Quervains Thyroiditis treated?
It is a self-limiting condition and supportive treatment with NSAIDs for pain and inflammation and beta blockers for symptomatic relief of hyperthyroidism is usually all that is necessary.
Who commonly gets De Quervains Thyroiditis?
It’s most commonly seen in women aged 20 to 50.
What is Hashimoto’s Thyroiditis?
Hashimoto’s thyroiditis is caused by the immune system attacking the thyroid gland, which damages it and makes it swell.
Does Hashimoto’s thyroiditis cause hyperthyroidism or hypothyroidism?
Initially it can cause a sudden release of thyroid hormones, resulting in hyperthyroidism, however overtime, as the thyroid gland becomes more and more damaged, it struggles to produce the hormones, so it causes hypothyroidism
When do people normally present with Hashimoto’s thyroiditis? Why the wait?
It may take months or even years for the condition to be detected because it progresses very slowly. Symptoms usually first start between the ages of 30 to 50 and the condition sometimes runs in families.
What is post-partum thyroiditis? After how long do they get it?
Postpartum thyroiditis is an uncommon condition that can affect women who have recently given birth. In postpartum thyroiditis, the immune system attacks the thyroid within around 6 months of giving birth.
Does post-partum thyroiditis thyroiditis cause hyperthyroidism or hypothyroidism?
Initially there is a temporary rise in thyroid hormone levels (thyrotoxicosis) and symptoms of an overactive thyroid gland. Then, after a few weeks, the gland becomes depleted of thyroid hormone. This leads to low thyroid hormone levels and symptoms of an underactive thyroid gland. However, not every woman with postpartum thyroiditis will go through both these phases.
How is post-partum thyroiditis treated?
Treatment depends on the phase of thyroiditis and degree of symptoms that a patient has.
Women presenting with thyrotoxicosis may be treated with beta blockers to decrease symptoms such as palpitations and tremors. As symptoms improve, the medication can be reduced and stopped since the thyrotoxic phase is transient.
The hypothyroid phase may be treated with thyroid hormone replacement. If the hypothyroidism is mild, and the patient has few, if any, symptoms, no therapy may be necessary. If thyroid hormone therapy is started, treatment should be continued for approximately 6-12 months and then reduced to see if thyroid hormone is required permanently.
What is silent thyroiditis?
Silent thyroiditis is very similar to postpartum thyroiditis, but it can affect men and women, and is not related to giving birth.
What is the course of thyroid levels / symptoms like in silent thyroiditis?
Like postpartum thyroiditis, there may be a phase of high thyroid hormone levels (thyrotoxicosis) causing symptoms of an overactive thyroid gland. This may be followed by symptoms of an under-active thyroid gland, before the symptoms go away in 12 to 18 months.
How is silent thyroiditis treated?
The same as for other types of thyroidits. If symptomatic in hyperthyoid phase, give beta blockers for symptoms.
When in hypothyroid stage, if it’s only mild / have no symptoms, then give nothing. If it’s more serious, then give levothyroxine. Make sure to check thyroid levels over the first 12-18 months to constantly reassess levels.
What is drug-induced thyroiditis?
Certain drugs can damage the thyroid and cause symptoms of hyperthyroidism (but can also cause symptoms of hypothyroidism in others)