Hyperthyroid (thyrotoxicosis)

Question 1

What is the physiology of thyroid hormone production>

Answer 1

1) hypothalamus secretes thyroid releasing hormone (TRH).
2) TRH stimulates pituitary gland to secrete Thyroid stimulating hormone (TSH).
3) . TSH binds to TSH receptors on the thyroid gland causing the release of thyroid hormones T3 and T4.
* T4 is activated into T3
4) A negative feedback loop from the increased T4/T3 levels causes the hypothalamus to stop producing TRH.

Question 2

What are the causes of hyperthyroidism?

Answer 2

1) AUTOIMMUNE : Grave’s disease (most common)
2) Toxic multi-nodular goitre (nodules sectrete T3/T4)
3) Toxic adenoma
4) pituitary adenoma
5) Drugs (excess thyroid hormone)
6) Iodine (amiodarone)

Question 3

What is the pathophysiology of graves disease?

Answer 3

1) TSH receptor autoantibodies activate the thyroid and cause secretion of T3/T4.

Question 4

What are the symptoms of hyperthyroidism?

Answer 4

1) Weight loss
2) Increased appetite
3) Heat intolerance and sweating
4) Fatigue and weakness
5) hyperactivity, Irritability
7) Tremor
8) palpitations
9) Insomnia
10) Thirst
11) Oligomenorrhoea

Question 5

what are the signs of hyperthyroidism?

Answer 5

Hands:

1) warm, sweaty palms
2) Palmar erythema
3) Onycholysis
4) clubbing
5) fin tremor

Eyes:

6) Exophthalmos
7) lid retraction
8) lid lag

Neck:

9) goitre
10) bruit

Heart:

11) tachycardia
12) atrial fibrillation
13) palpitations

Legs:
14) Pretibial myxoedema

15) HYPEReflexia

General inspection:

16) anxiety
17) restless
18) irritable
19) hair loss
20) weight loss

Question 6

what are the complications of hyperthyroidism?

Answer 6

1) congestive heart failure
2) angina
3) atrial fibrillation
4) decreased bone density ( osteoporosis)
5) grave’s ophthalmology (blurred vision)
6) grave’s dermapothy (elephantitis dermopathy)
7) gynaecomastia

Question 7

What are the investigations done for hyperthyroidism?

Answer 7

1) Thyroid function test:
- TSH hormone low
- T3/T4 high

2) Ultrasound (for toxic adenoma or toxic multinodular goitre)
3) Thyroid scan (scintiscanning) - labelled iodine injected into thyroid. In grave’s disease there will be greater uptake due to the increased activity of gland. Iodine used to make T3/T4.
4) increased TSH receptor autoantibodies indicates grave’s disease.

Question 8

What are the treatments for hyperthyroidism?

Answer 8

1) Pharmacological :
- Antithyroid drugs such as THIOMIDE inhibits the enzyme that helps to synthesise T3/T4.

• Beta Blockers decreases sympathetic activity by binding to beta receptors.
  2) RADIOIODINE Therapy. - radioactive iodine is injected into the gland. It destroys the tissue so less T3/T4.
  3) Surgery -partial or total ectomy. (risk of recurrent laryngeal being cut)