Case 9- Thyroid disorders Flashcards Preview

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Flashcards in Case 9- Thyroid disorders Deck (39)
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1
Q

What can synthetic thyroid hormones treat

A

Hypothyroidism (myxoedema), diffuse non-toxic goitre, Hashimoto’s thyroiditis (lymphadenoid goitre) and thyroid carcinoma

2
Q

Aim of treatment for thyroid disorders

A

Replacing hormones not augmentation of thyroxine synthesis

3
Q

Levothyroxine sodium (T4, thyroxine sodium)

A

First line treatment for hypothyroidism, maintenance therapy. The dose is adjusted according to response in the patient and is taken orally 30 min before meals/caffeine.

4
Q

Liothyronine sodium (synthetic T3)

A

Used in severe hypothyroid states such as myxoedema coma, where a rapid response is needed. Patients may also need IV fluid and steroids as additional therapy in severe hypothyroidism conditions

5
Q

What can thyroid disorders be mistaken for

A

An overdose may mimic hyperthyroidism and thyrotoxicosis and may cause cardiac arrhythmias, angina pectoris or cardiac failure. Hypothyroidism can be confused with ischaemia.

6
Q

Causes of Hyperthyroidism

A

1) Thyrotoxicosis
2) Diffuse toxic goitre (Grave’s disease)
3) Toxic nodular goitre

7
Q

Thyrotoxicosis

A

Overproduction of thyroid hormones. Presents with high metabolic rate, increase in skin temperature and sweating (heat tolerance), nervousness, tremor, increased appetite, weight loss and tachycardia. This can be caused by diffuse toxic goitre (Grave’s Disease) or due to toxic nodular goitre.

8
Q

Diffuse toxic goitre (Grave’s disease)

A

An autoimmune disease targeting and activating TSH receptors leading to an increase in thyroxine secretion

9
Q

Toxic nodular goitre

A

Caused by a benign tumour or adenoma which secretes thyroxine

10
Q

Radioactive sodium iodide (131I)

A

Administered orally and is used for treatment of thyrotoxicosis at all ages. It is useful if drugs are not tolerated by the patient or when there are problems with compliance. Can be used when there is evidence of cardiac disease or following a relapse after thyroidectomy.

11
Q

Mechanism of action of radioactive sodium iodide

A

It works by emitting beta and gamma radiation causing destruction of thyroid tissue. Loss of tissue makes it likely that the patient will require subsequent T4 replacement therapy.

12
Q

Contradiction of radioactive sodium iodide

A

Children and during pregnancy

13
Q

Diagnostic role of radioactive sodium iodide

A

It can be given at a tracer dose to assess thyroid function

14
Q

Thioureylenes

A

Antithyroid dugs that are used to prepare patients for thyroidectomy or for long term management. Used to treat Hyperthyroidism

15
Q

Carbimazole

A

Most commonly used antithyroid drug, decreases output of thyroid hormones. Used to treat Hyperthyroidism. Gradual reduction in signs and symptoms, after 4 weeks metabolic and pulse rate are back to normal. It inhibits the iodination of thyroglobulin

16
Q

Carbimazole contraindications

A

Avoid during pregnancy

17
Q

How long does carbimazole take to have its full effect

A

A long time as T4 has a long half life and may be stored

18
Q

What other drugs can Carbimazole be combined with

A

Can be combined with levothyroxine sodium daily to form a blocking-replacement regimen which is given for an 18 month duration. You stop thyroid hormone production and then replace it with a more suitable amount.

19
Q

Side effects of Carbimazole

A

Neutropenia (low white blood cells) and agranulocytes (lack of granulocytes). If evidence of bone marrow suppression or neutropenia then stop treatment. Avoid using in sever hepatic impairment. Over treatment can cause hypothyroidism, may cause foetal goitre.

20
Q

Propylthiouracil

A

Used to treat hyperthyroidism. It is similar to carbiamazole but blocks T4 to T3 conversion in peripheral tissues. Its use is reserved for patients not responding to carbiamazole

21
Q

Iodine/Iodide

A

Treatment for hyperthyroidism. Iodine is converted in-vivo to iodide. High doses of iodine inhibit secretion of thyroid hormones over 10-14 days. The underpinning mechanism is uncertain but may be due to reduced blood supply to the thyroid. High dose Iodine/Iodide may be used in preparation of patients for surgical resection.

22
Q

Propanolol hydrochloride

A

Used in treating symptoms of hyperthyroidism such as tachycardia, arrhythmias and tremores. It is used alongside radioactive iodine treatment. Does’nt treat underlying cause.

23
Q

Treatment for thyrotoxic crisis (thyroid storm)

A

IV fluid, propranolol hydrochloride, Hydrocortisone, oral iodine solution and Carbimazole or propylthiouracil.

24
Q

Non-toxic goitre

A

Swelling of the neck, no change in thyroid hormone levels but a decrease in Iodide levels, can be treated with radioactive iodine. Causes hyperthyroidism

25
Q

Hyperthyroidism

A

Excessive production and secretion of thyroid hormones leading to thyrotoxicosis (an excess of circulating thyroid hormone)

26
Q

Signs and symptoms of hyperthyroidism

A

Goitre, hyperactivity, disturbed sleep, fatigue, palpitations, anxiety, heat intolerance, increased appetite with unintentional weight loss, and diarrhoea.

27
Q

Overt hyperthyroidism

A

When TSH levels are below the reference range and T3 or T4 levels are above the reference range

28
Q

Signs of Thyrotoxicosis

A

An acute presentation with pyrexia, tachycardia and delirium. You will admit the patient for monitoring, give them fluid resuscitation and anti-arrhythmic drugs

29
Q

Exophthalmos

A

Bulging of the eyeball due to Grave’s disease, as a result of inflammation and swelling.

30
Q

How to treat severe cases of hyperthyroidism

A

You can have surgery to remove the whole gland or just nodules. This stops production of the thyroid hormone. They will require Levothyroxine for life to replace TSH

31
Q

Hypothyroidism

A

The underproduction and secretion of thyroid hormones

32
Q

Signs and symptoms of hypothyroidism

A

Fatigue, weight gain, constipation, menstrual irregularities, depression, dry skin and thinning hair.

33
Q

Complications of hypothyroidism

A

Coronary heart disease, impaired fertility, impaired concentration and pregnancy complications

34
Q

Primary hypothyroidism

A

When the condition arises from the thyroid gland and may be caused by iodine deficiency, autoimmune disease (such as Hashimoto’s thyroiditis), radiotherapy, surgery or drugs, rather than due to a pituitary or hypothalamic disorder (secondary hypothyroidism).

35
Q

Overt hypothyroidism

A

Decreased TSH and an increased T4 level

36
Q

Thyroid function test

A

Identifies levels of TSH, T3 and T4

37
Q

TPO antibodies

A

Raised in Grave’s

38
Q

Thyroid disease- X-ray/ ultrasound/ biopsy

A

To assess the thyroid for cancer

39
Q

How to manage overt hyperthyroidism

A

Overt hyperthyroidism is managed with beta blockers and carbimazole. Carbimazole may cause development of a rash but this can be treated with antihistamines.