Clinical Topic 6: Pituitary, Adrenal, Thyroid Disease

Question 1

What hormones are released by the anterior pituitary gland?

Answer 1

• FSH
• LH
• Growth hormone
• Prolactin
• ACTH
• TSH

Question 2

What hormones are released by the posterior pituitary gland?

Answer 2

• Oxytocin

- ADH

Question 3

What hormones are released at each level of the HPA axis?

Answer 3

Hypothalamus: Corticotropic releasing hormone (CRH)
Pituitary gland: Adrenocorticotropic releasing hormone (ACTH)
Adrenal: Glucocorticoids

Question 4

What hormones are released at each level of the HPT axis?

Answer 4

Hypothalamus: Thyroid releasing hormone (TRH)
Pituitary gland: Thyroid stimulating hormone (TSH)
Thyroid gland: T3 and T4

Question 5

What hormones are released by the Thyroid gland?

Answer 5

T3, T4

Calcitonin

Question 6

What cells release T3, T4 and Calcitonin in the Thyroid?

Answer 6

T3 and T4 Follicular cells

Calcitonin: Parafollicular cells (C cells)

Question 7

What is the most common and second most common form of Hyperthyroidism?

Answer 7

Graves disease (most common)

Toxic multinodular goitre (2nd commonest)

Question 8

How does Graves disease cause hyperthyroidism?

Answer 8

TSH antibodies stimulate thyroid follicular cells to secrete T3 and T4

Question 9

How does a Toxic multi-nodular / single nodular goitre cause hyperthyroidism?

Answer 9

The nodules themselves secrete T3 and T4

Question 10

How does Thyroiditis cause hyperthyroidism?

Answer 10

Inflammation of the thyroid gland causes release of preformed hormones from follicular cells

Question 11

Give examples of drugs which can cause Hyperthyroidism / Hypothyroidism (TAIL)

Answer 11

Thyroxine
Amiodarone
Iodine
Lithium

Question 12

How does pregnancy cause hyperthyroidism?

Answer 12

Gestional hyperthyroidism is caused by beta-hCG stimulation of follicular cells to release T3/T4

Question 13

How does a pituitary adenoma cause hyperthyroidism?

Answer 13

Excess TSH release causing T3/T4 release

Question 14

In secondary hyperthyroidism, what are the TSH, T3, T4 levels?

Answer 14

TSH - High (due to impaired feedback)

T3/T4 - High

Question 15

In subclinical hyperthyroidism, what are the TSH, T3, T4 levels?

Answer 15

TSH - Low (due to feedback)

T3/T4 - Normal

Question 16

What are the uptake patterns in a radionuclide scan in a:

• Graves disease patient
• Toxic single nodule patient
• Toxic multinodular patient
• Thyroiditis patient

Answer 16

• Graves disease patient - diffuse uptake
• Toxic single nodule patient - single area of uptake
• Toxic multinodular patient - patchy uptake
• Thyroiditis patient - reduced / absent uptake

Question 17

What is the best advice to give a Grave’s disease patient to limit their chance of developing Thyroid eye disease?

Answer 17

Stop smoking

Question 18

What non-specific treatment can be offered to all Hyperthyroidism patients, regardless of the cause?

Answer 18

Beta blockers

Question 19

What are the treatment options for Graves disease?

Answer 19

Beta blockers +

Anti-thyroid drugs, thyroidectomy or radio-iodine

Question 20

What are the treatment options for a toxic nodular goitre?

Answer 20

Beta blockers +

Due to relapse from anti-thyroid drugs, radio-iodine is preferred or thyroidectomy

Question 21

What are the treatment options for thyroiditis?

Answer 21

Beta blockers +

Resolve on their own

Question 22

Give three examples of anti-thyroid drugs. What is their MoA?

Answer 22

Carbimazole, Methimazole
Propylthiouracil

They inhibit thyroid peroxidase

Question 23

Out of Carbimazole, Methimazole and Propylthiouracil. Which are preferred?

Answer 23

Carbimazole and Methimazole > Propylthiouracil*

However, Prophythiouracil is preferred during pregnancy

Question 24

What are the adverse side-effects associated with Anti-thyroid drugs? Are there any specific side-effects

Answer 24

Skin rash, itchiness, joint pain, agranulocytosis

In Carbi / Methamizole -> Cholestatic liver disease
In Prophylthiouracil -> Fulminant hepatic failure

Question 25

What are the two dosing regimens for Anti-thyroid drugs?

Answer 25

- Titration regimen -> Dose of drug based on TFTs to partially block T4 secretion - Block-and-replace regimen -> High dose of Anti-thyroid drug + Levothyroxine

Question 26

State two side-effects of Radio-iodine therapy for hyperthyroidism

Answer 26

- Hypothyroidism - Worsening thyroid eye disease

Question 27

What is the most common hypothyroidism disorder in the developed world? In the developing world?

Answer 27

Developed world: Auto-immune thyroiditis (Hashimoto's) Developing world: Iodine deficiency

Question 28

What are some complications of thyroidectomy surgery?

Answer 28

Vocal cord paralysis Hypoparathyroidism (hypocalcaemia)

Question 29

How are periods affected in Hyperthyroidism and Hypothyroidism?

Answer 29

Hyperthyroidism: Oligomenorrhoea, amenorrhoea Hypothyroidism: Menorrhagia

Question 30

Myxoeodema coma is associated with Hyperthyroidism or Hypothyroidism?

Answer 30

Hypothyroidism

Question 31

What two findings on blood tests are common in patients with untreated Hypothyroidism?

Answer 31

Hyponatraemia | Hypercholesterolaemia

Question 32

Failure to comply with Thyroxine treatment in Hypothyroidism patients results in what affect on TSH and free T4?

Answer 32

High TSH | Low free T4

Question 33

Primary hypothyroidism is denoted by what levels of T4 and TSH?

Answer 33

Low free T4 | High TSH

Question 34

Secondary hypothyroidism is denoted by what levels of T4 and TSH?

Answer 34

Low free T4 | Low or normal TSH

Question 35

Subclinical hypothyroidism is denoted by what levels of T4 and TSH?

Answer 35

Normal T4 | High TSH

Question 36

What is the main treatment for Hypothyroidism?

Answer 36

Lifelong Levothyroxine

Question 37

What antibodies can be tested to diagnose Hashimoto's?

Answer 37

Thyroid peroxidase antibodies

Question 38

What is the characteristic finding on palpating Subacute (de Quervain's) thyroiditis? In the history for Subacute Thyroiditis, what may be found?

Answer 38

Tender thyroid gland A previous viral infection

Question 39

What is Pemberton's sign?

Answer 39

When a patient presents with facial flushing on raising their arms. Caused by compression of vascular structures in thoracic inlet Due to a goitre

Question 40

When might a euthyroid goitre be excised?

Answer 40

- Due to malignancy - If patient has symptoms of tracheal obstruction - When goitre is rapidly growing / cosmetic problem

Question 41

What are the investigations of choice for a goitre?

Answer 41

TFTs TSH and TPO antibodies Ultrasound

Question 42

What is the treatment for Myxoedemic coma?

Answer 42

Levothyroxine + Hydrocortisone

Question 43

In Sick Euthyroid syndrome, what are the expected T3, T4 and TSH levels?

Answer 43

T3 - Low T4 - Low TSH - Low / Normal

Question 44

What is Waterhouse-Friederich syndrome?

Answer 44

Bleeding of adrenal gland due to meningitis

Question 45

What is Nelson's syndrome?

Answer 45

ACTH producing adenoma that occurs after the removal of both adrenal glands (bilateral adrenalectomy) which is an operation used for Cushing's syndrome

Question 46

THYROID STORM 1. What is it? 2. What may it be caused by? 3. What are the features? 4. What is the management?

Answer 46

1. A life-threatening complication of thyrotoxicosis 2. May be caused by thyroid surgery, non-thyroid surgery, trauma, infection 3. Fever, hypertension, tachycardia, nausea, vomiting, confusion, agitation 4. Treat the underlying cause Analgesia Beta-blockers i.e. Propranolol Anti-thyroid drugs i.e. Methimazole, Propylthiouracil Hydrocortisone Lugol's Iodine

Question 47

MYXOEDEMA COMA 1. What is it? 2. What are the two main features? 3. What is the management?

Answer 47

1. A severe form of hypothyroidism 2. Hypothermia and confusion 3. IV fluids, IV thyroid replacement, IV steroids, rewarming