Pituitary and thyroid diseases

Question 1

describe the endocrine system

Answer 1

a complex network of glands that produce and release hormones that control and co-ordinate many important processes in the body

Question 2

what hormones do the adrenal glands produce?

Answer 2

• cortisol
• aldosterone
• adrenaline
• noradrenaline

Question 3

what is the role of the hypothalamus? where is it located? what hormones does it produce?

Answer 3

part of the lower brain which tells the pituitary gland when to release hormones
* produces releasing hormones - TRH (thyrotropin releasing hormone), GnRH (gonadotropin releasing hormone), CRH (corticotropin releasing hormone)

Question 4

what hormoes do the islet cells of the pancreas produce?

Answer 4

• insulin (beta cells)
• glucagon (alpha cells)

Question 5

what do the paratyroid glands do?

Answer 5

controls bood calcium levels

Question 6

what does the pituitary gland do?

Answer 6

controls other glands to produce hormones

Question 7

what does the thyroid gland do?

Answer 7

produces hormones that control metabolism, growth and development

Question 8

why can disorders of the endocrine system occur?

3

Answer 8

• hormone levels are too high
• hormone levels are too low
• body does not respond to hormones in the expected way

Question 9

what can endocrine diseases cause?

Answer 9

• too much or too little hormone production
• development of tumours

Question 10

where is the pituitary gland located?

Answer 10

at the base of the brain, below the hypothalamus

Question 11

what hormoes does the anterior pituitary gland produce?

Answer 11

• TSH - thyroid stimulating hormone
• ACTH - adrenocorticotropic hormone
• GH - growth hormone
• LH, FSH, prolactin

Question 12

what hormones does the posterior pituitary gland produce?

Answer 12

• ADH - anti-diuretic hormone
• oxytocin

Question 13

what is the difference between a functional and non-functional adenoma?

Answer 13

• functional adenomas actively produce and release excess hormones
• non-functional adenomas do not secrete significant amounts of hormone and can cause symptoms by growing and compressing glands

Question 14

what affect can pituitary tumours have on the optic nerve? how can this be treated?

Answer 14

• pituitary adenomas can grow to compress the optic nerve and cause vision problems
• if the tumour affects the optic chiasm, it can affect vision in both eyes
• treated with trans-sphenoidal surgery

Question 15

describe the negative feedback loop of growth hormone

Answer 15

• hypothalamus releases GHRH (growth hormone releasing hormone)
• GHRH acts on the **anterior pituitary **gland to release GH (growth hormone)
• GH is converted to IGF-1 (insulin growth factor) in the liver and decreases secretion of GH by stimulating stomatostatin
• excess GH also inhibits release of GHRH

Question 16

what happens when a person has insufficient growth hormone?

Answer 16

• growth failure in children
• metabolic changes in adults - increased fat, reduced vitality

Question 17

what happens when a person has excess growth hormone?

Answer 17

• gigantism in children
• acromegaly in adults

Question 18

what causes acromegaly?

Answer 18

• insidious onset
• benign pituitary tumour

Question 19

what are the physical features of acromegaly?

Answer 19

• coarse features
• enlarges supra-orbital ridges
• broad nose
• thickened lips and soft tissues

Question 20

what conditions are associated with acromegaly? why?

Answer 20

• carpel tunnel syndrome - enlarged hands
• type 2 DM - GH causes raised blood glucose levels so insulin resistance
• cardiovascular disease (ischaemic HD, acromegalic cardiomyopathy) - thickening of heart muscle

Question 21

§

what are the dental aspects of a person with acromegaly?

Answer 21

• enlarged tongue
• interdental spacing
• ‘shrunk’ dentures (mouth grows too large)
• reverse overbite / class 3 occlusion

Question 22

what are the tyroid hormones and what do they do?

Answer 22

T3 and T4 - regulate metabolism

Question 23

what is hyperthyroidism? what does it cause?

Answer 23

an excess of T3 and T4 produced, causing increased metabolism

Question 24

what are the signs of hypertyhroidism?

5

Answer 24

• warm, moist skin
• tachycardia, atria fibrillation
• increased blood pressure
• tremor and hyperreflexia
• eyelid retraction and lid lag

Question 25

what are the symptoms of hyperthyroidism | 6

Answer 25

* hot and excessive sweating * weight loss * diarrhoea * heart palpitations * muscle weakness * irritable, manic, anxious

Question 26

what are the causes of hyperthyroidism? | 6

Answer 26

* Grave's disease * toxic multi-nodular goitre * toxic adenomas * thryoiditis * exogenous thyroid hormone intake * pituitary tumour

Question 27

what is Grave's disease? what people is it more common in? what are the symptoms?

Answer 27

**auto-immune condition** which causes the tyroid gland to produce more hormones * common in **women over 30** * **diffuse goitre** * **opthalmopathy** - oedema and erythema of periorbital and conjunctivae, upper eyelid retraction

Question 28

how can pituitary tumours cause hyperthyroidism?

Answer 28

benign pituitary adenoma which produces TSH

Question 29

describe how thyroid levels are regulated

Answer 29

* **hypothalamus** produces **TRH** (thyrotropin releasing hormone) * TRH works on the **anterior pituitary gland** to release **TSH** (thyroid stimulating hormone) * TSH works on the **thyroid gland** to produce **T3** and **T4** * **T4** negatively regulates the production of **TRH** in the **hypothalamus** * **T3** negatively regulates the production of **TSH** in the **anterior pituitary**

Question 30

what is hypothyroidism and what does it cause?

Answer 30

a **lack/no** T3 or T4 hormone released which causes **reduced metabolism**

Question 31

what are the signs of hypothyroidism? | 6

Answer 31

* dry, coarse skin * bradycardia * hyperlipidaemia (high colesterol) * confusion * goitre (Hashimoto's) * delayed reflexes

Question 32

what are the symptoms of hypothyroidism? | 9

Answer 32

* tiredness * cold intolerance * weight gain * constipation * hoarse voice * puffed face and extremities * angina * slow/poor memory * hair loss

Question 33

what are the primary and secondary causes of hypothyroidism? | 6,1

Answer 33

primary * autoimmune thyroiditis (Hashimoto's) * idiopathic atrophy * radioiodine treatment / thyroidectomy surgery * iodine deficiency * drugs * congenital secondary * hypothalmic/pituitary disease

Question 34

what is Hashimoto's thyroiditis and what are the presenting features?

Answer 34

* **autioimmune disease** usually genetic which gradually **destroys** the thyroid gland * presents with **goitre** and other hypothyroidism features

Question 35

how can a pituitary tumour cause hypothyroidism?

Answer 35

* there is **limited space** for expansion of pituitary gland in Sella Tunica * pituitary tumour can **expand** and **compress** normal pituitary tissue * the compressed cells **produce abnormally low TSH**, leading to less T3 and T4 produced and therefore hypothyroidism

Question 36

what are the investigations for thyroid disease? | 3

Answer 36

* **blood tests** - T3, T4, TSH levels * **imaging** - ultrasound, radiopaque scan * **tissue samples** - fine needle aspiration/biopsy (FNA, FNB)

Question 37

what blood results would you find with primary hyperthyroidism?

Answer 37

* high T3 and T4 * low TSH

Question 38

what blood results would you find with secondary hyperthroidism?

Answer 38

* high T3 and T4 * high TSH

Question 39

what blood results would you find with primary hypothyroidism?

Answer 39

* low T4 * high TSH

Question 40

what blood results would you find with secondary hypothyroidism?

Answer 40

* low T4 * low TSH

Question 41

what are the treatments for hyperthyroidism?

Answer 41

* **medication** - carbimazole, beta blockers * **radioiodine 131i** * **surgery** - partial thyroidectomy

Question 42

what is the treatment for hypothyroidism?

Answer 42

* T4 (thyroxine) tablets

Question 43

how does thyroid cancer usually present?

Answer 43

* thyroid swelling * papillary or follicular in younger patients * undifferentiated in elderly * cold nodes on radioiosotope scan

Question 44

what are the dental aspects of thyroid disorders? how do hypo and hyperthyroid patients differ?

Answer 44

* **goitre** detectable at the dentist * hyperthyroidism - pain, anxiety and psychiatric problems, caution for treatment until controlled * hypothyroidism - avoid use of sedative if severe, can present as burning mouth