Diseases of the Endocrine System Flashcards

1
Q

What is the role of the endocrine glands?

What is paracrine and autocrine secretion?

A

endocrine glands secrete hormones directly into the blood stream and act systemically

paracrine system secretes hormones that act locally

autocrine secretion affects the cell secreting the protein

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2
Q

Where is the pituitary gland situated?

What does it weigh?

A

situated in the sella turcica beneath the hypothalamus

it weighs between 500 - 1000 mg

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3
Q

What are the 2 parts of the pituitary gland?

A

anterior:

  • 75% of the gland is formed by the anterior lobe
  • this is formed by an outpouching of the oral cavity (Rathke’s pouch)

posterior:

  • 25% of the pituitary gland is the posterior lobe
  • this is formed by downgrowth of the hypothalamus
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4
Q

What is adenohypophysis?

A

it is another term for the anterior part of the pituitary gland

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5
Q

What is meant by neurohypophysis?

A

another term for the posterior lobe of the pituitary gland

it stores and releases oxytocin and vasopressin produced in the hypothalamus

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6
Q

What are the different causes of anterior pituitary hypofunction?

A
  1. tumours - non-secretory adenoma, metastatic carcinoma
  2. trauma
  3. infarction
  4. inflammation - granulomatous, autoimmune, other infections
  5. iatrogenic
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7
Q

What are the majority of primary pituitary tumours?

What causes the effects of the tumour?

A

the vast majority of adenomas are benign

they may be derived from any hormone producing cell

if functional, the clinical effect is secondary to the hormone being produced

local effects are due to pressure on the optic chiasma or adjacent pituitary

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8
Q

What are the 3 different types of anterior pituitary adenoma?

A

prolactinoma:

  • this is common
  • causes galactorrhoea and menstrual disturbance

growth hormone secreting:

  • causes gigantism in children and acromegaly in adults

ACTH secreting:

  • Cushing’s syndrome
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9
Q

What is the anatomy of the thyroid gland like?

How much does it weigh?

A

bilobed organ joined by an isthmus encased in a thin fibrous capsule

it is located at the level of the 5th, 6th and 7th vertebrae in the anterior neck and in close proximity to the trachea

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10
Q

What is the weight of the thyroid gland?

A

average weight is 18g in adult males and 15g in adult females

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11
Q

What are the anatomical relationships of the thyroid gland?

A

abuts the thyroid cartilage of the larynx

the recurrent laryngeal nerve is located in the tracheo-oesophageal groove close to the posterior aspect of the lateral lobes

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12
Q

Label the diagram

A
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13
Q

Label the diagram

A
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14
Q

What is the origin of the thyroid gland like?

A

it has 2 parts

the main part migrates from the foregut to the anterior neck

the ultimobranchial body forms in branchial arches and fuses with the main bit laterally

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15
Q

What does the remnant of the thyroid gland in the foregut form?

A

foramen caecum

this is at the junction between the anterior 2/3 and posterior 1/3 of the tongue

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16
Q

What is Hashimoto’s?

(chronic lymphocytic thyroiditis)

Who is more commonly affected?

A

an autoimmune chronic inflammatory disorder associated with diffuse enlargement and thyroid autoantibodies

it is more common in females

peak age is 59 years

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17
Q

What happens in Hashimoto’s disease?

A

there is a diffusely enlarged non-tender gland

lymphocytic infiltration of thyroid parenchyma, often with germinal centre formation

many patients become hypothyroid

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18
Q

What clinical feature is raised in Hashimoto’s?

What are the increased risks associated with this condition?

A

serum thyroid antibodies are elevated

there is an 80 fold increased risk of thyroid lymphoma

there is an increased risk of papillary carcinoma of the thyroid

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19
Q

What is diffuse hyperplasia (Graves’ disease)?

Who tends to be more affected?

A

an autoimmune process results in clinical hyperthyroidism and diffuse hyperplasia of the follicular epithelium

it is more common in females

peak in third and fourth decades

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20
Q

What are the physical findings in Graves’ disease?

A
  1. pretibial myxoedema
  2. hair loss
  3. wide-eyed stare or proptosis
  4. tachycardia
  5. hyperactive reflexes
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21
Q

What are the signs of Graves’ disease?

What clinical marker will be elevated?

A

the thyroid is diffusely enlarged

T3 and T4 will be elevated

TSH will be suppressed

There will be thyroid autoantibodies, especially thyroid stimulating immunoglobulin

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22
Q

What is meant by multinodular goitre?

A

enlargement of the thyroid with varying degrees of nodularity

1 or more thyroid nodules discovered by a patient or health care provider

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23
Q

What are the signs of multinodular goitre?

What may it be mistaken for?

A

most patients are euthyroid

the dominant nodule may be mistaken clinically for thyroid carcinoma

large nodules may cause tracheal compression or dysphagia

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24
Q

What does euthyroid mean?

A

having a normally functioning thyroid gland

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25
Q

What is follicular adenoma?

Who does it usually affect?

A

benign encapsulated tumour with evidence of follicular cell differentiation

it affects more females

there is a wide age range, usually from fifth to sixth decade

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26
Q

What are the symptoms of follicular adenoma?

How is it usually detected?

A

painless neck mass, often present for years

there is a solitary nodule involving only one lobe

it is usually cold nodule on radioactive iodine imaging

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27
Q

What are the different types of malignant tumours of the thyroid?

A
  • differentiated thyroid carcinoma
  • medullary carcinoma
  • anaplastic carcinoma
  • malignant lymphoma
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28
Q

What is the most commonest type of thyroid carcinoma?

What people are most commonly affected?

A

papillary carcinoma

female predominance is 2.5:1

it has a wide age range mean of 43 years

29
Q

What is papillary carcinoma?

What conditions is it associated with?

A

familial, autosomal dominant non-medullary thyroid carcinoma

seen in FAP and Cowden’s syndrome

treated by therapeutic irradiation

30
Q

What genetically causes papillary carcinoma?

A

activation of RET or NTRK1

this is caused by a variety of chromosomal translocations or inversions

fusion of RET tyrosine kinase regions with constitutively expressed thyroid proteins

BRAF V600E mutation

RAS mutations

31
Q

What is the macroscopic appearance of papillary carcinoma like?

A
  • ill defined, infiltrative
  • some encapsulated
  • may be cystic
  • granular
32
Q
A
33
Q

What are the 5 different types of follicular neoplasms?

A
  • follicular adenoma
  • minimally invasive follicular carcinoma
  • widely invasive follicular carcinoma
  • hurthle cell neoplasms
  • Ras mutations
34
Q

WHat % of thyroid cancers are follicular carcinomas?

How do patients present?

A

10-20% of all thyroid cancers

90% present with a solitary nodule in the thyroid

10% present with distant metastasis

35
Q

What is the difference between a minimally invasive and widely invasive follicular carcinoma?

A

minimally invasive < 5% metastasis

widely invasive is > 60% metastasis

36
Q

What is Hurthle cell carcinoma?

Who does it usually affect?

A

accounts for 3% of all differentiated thyroid carcinomas

the median age is 53 (range of 24 - 85 years)

sex ratio of F:M is 7 : 3

37
Q

What is the clinical behaviour of Hurthle cell carcinoma?

What are the most common haematogenous sites?

A

unlike follicular carcinoma there is a significant incidence of cervical lymph node metastases

common haematogenous sites are bone, liver and lung

38
Q

What is primary hyperparathyroidism?

A

excessive secretion of parathyroid hormone from one or more glands

39
Q

What is meant by secondary hyperparathyroidism?

A

hyperplasia of glands with elevated PTH in response to hypocalcaemia

this is from renal insufficiency, malabsorption or vitamin D deficiency

40
Q

What is meant by tertiary hyperparathyroidism?

A

this occurs in association with longstanding secondary hyperparathyroidism

41
Q

What is the incidence of primary hyperparathyroidism?

A

25-28 cases per 100,000 population

Caucasian women over 60 - 190/100,000

42
Q

What is the pathogenesis of primary hyperparathyroidism?

A
  1. aging, tumorigenesis in general
  2. association with ionising irradiation
  3. MEN 2a
43
Q

What is primary hyperparathyroidism associated with?

A
  1. asymptomatic
  2. arterial hypertension
  3. psychiatric problems
  4. hypercalcaemia
  5. decreased renal function
  6. osteoporosis
  7. hyperparathyroid bone disease
  8. hypercalcaemia symptoms
  9. urolithiasis
44
Q

What malignancies is primary hyperparathyroidism associated with?

A
  1. single adenoma - 85-90%
  2. diffuse chief or clear cell hyperplasia - 10-15%
  3. carcinoma - 1%
45
Q

What is parathyroid adenoma?

How many people does it affect and how does it present?

A

an encapsulated benign neoplasm of parathyroid cells

it affects 1 per 1000 people

it presents with symptoms of hypercalcaemia

46
Q

What is parathyroid adenoma associated with?

A

associated with MEN1 and MEN2 syndrome , hyperparathyroidism and jaw tumour syndrome

it involves a single enlarged parathyroid gland

all the other remaining glands are suppressed and small

47
Q

What is secondary and tertiary hyperparathyroidism?

In what patients is it common?

A

non-neoplastic increase in parathyroid parenchymal cell mass within all parathyroid tissue with a known stimulus

it is common in patients with renal failure and on dialysis

it has identical pathological features to primary hyperplasia and may be associated with massive gland enlargement

48
Q

What is parathyroid carcinoma?

What are the symptoms related to?

A

malignant tumour derived from parathyroid parenchymal cells

symptoms are referable to excess calcium

49
Q

How is parathyroid carcinoma treated?

What is the survival like?

A

it is indolent with recurrences common (about 50% of cases)

treated with surgery

50% of cases have 10-year survival

50
Q

Label the adrenal gland

A
51
Q

What is Cushing’s syndrome?

A

a collection of signs and symptoms due to prolonged exposure to cortisol

paraneoplastic Cushing’s is seen in small cell lung carcinoma

52
Q

What are the endogenous and exogenous causes of Cushing’s syndrome?

A

exogenous causes:

  • excessive glucocorticoid medication

endogenous causes:

  • adrenal cortical tumours
  • adrenal cortical hyperplasia
  • ACTH secreting pituitary adenoma
53
Q

What are the signs and symptoms of Cushing’s syndrome?

A
  • hypertension
  • moon face
  • central obesity
  • buffalo hump
  • weak muscles
  • osteoporosis
  • insomnia
  • excessive sweating
  • mood swings
  • headaches
  • chronic fatigue

Women may have increased hair growth (hirsuitism) and irregular menstruation

54
Q

What is Conn’s syndrome?

A

hyperaldosteronism - primary and secondary

more common in women and those 30-50 years old

excess production of the hormone aldosterone by the adrenal cortex leads to low renin levels

this is controlled by the renin-angiotensin system

55
Q

What are the symptoms and signs of Conn’s syndrome?

A
  • high blood pressure
  • headache
  • muscular weakness
  • muscle spasms
  • excessive urination
  • cardiac arrhythmias
56
Q

What is the aetiology of Conn’s syndrome?

A

aetiology includes adrenal cortical hyperplasia, adenoma and familial hyperaldosteronism

57
Q

What is addison’s disease?

A

primary adrenal cortical insufficiency caused by adrenal dysgenesis, adrenal destruction, autoimmune adrenalitis, tuberculosis

secondary is due to failure of ACTH secretion

58
Q

What are the symptoms of Addison’s disease?

A

the autoimmune form is the most common

triad of hyperpigmentation, postural hypotension and hyponatraemia

59
Q

What is the treatment for Addison’s disease?

A

treatment with long term steroid replacement

it has a high mortality is it is not diagnosed

60
Q

What is an adrenal cortical nodule?

Who is more commonly affected?

A

a benign non-functional nodule of the adrenal cortex

it affects between 1.5 and 3% of the population

it is higher in elderly, hypotensive and diabetic patietns

61
Q

What are the symptoms of adrenal cortical nodule?

What is the treatment?

A

there are no clinical symptoms and it is an incidental discovery on radiographic studies

no treatment is required

62
Q

What is adrenal cortical adenoma?

What is the incidence like?

A

benign neoplastic proliferation of adrenal cortical tissue

symptoms are related to endocrine hyperfunction

incidence between 1-5% of the population

63
Q

What are the symptoms of adrenal cortical adenoma?

A

aldosterone prodicing tumours cause Conn’s syndrome

cortisol-producing tumours cause Cushing’s syndrome

rare tumours cause virilisation

64
Q

What is adrenal cortical carcinoma?

A

a malignant counterpart of the adrenal cortical adenoma

it accounts for 3% of endocrine neoplasms

65
Q

What are the symptoms of adrenal cortical carcinoma?

What is the prognosis like?

A

symptoms are related to hormone excess

abdominal mass is present

prognosis is age and state dependent

5-year survival rate is about 70%

66
Q

WHat is phaeochromocytoma?

What are the different types and causes?

A

catecholamine-secreting tumour arising from the adrenal medulla

10% are bilateral, 10% are extra-adrenal, 10% are malignant, 10% are familial and 10% are seen in children

most cases are sporadic but familial syndromes MEN2a and 2b, von Recklinghausen’s disease and vin Hippel-Lindau disease

67
Q

What are the symptoms of phaeochromocytoma?

What is prognosis like?

A

symptoms of hypertension, palpitation, headaches and anxiety

elevated urine catecholamines, adrenaline and noradrenaline

excellent prognosis when benign and properly managed surgically

malignant tumour may pursue an aggressive course

68
Q
A