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Medicine 3 > 8 adrenal disease > Flashcards

8 adrenal disease Flashcards

1
Q

define stress

A

a state of threatened homeostasis or dysharmony;

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2
Q

how does the body respond to stress to re establish homeostasis?

A
  • arousal, alertness, vigilance
  • Redirection of energy:
    • Increased CV tone, ventilation
    • Increase glucose availability
    • Decrease energy consuming activities (digestion and reproduction)
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3
Q

what is a stressor?

A

stimulus that induces state of stress

  • psychological / emotional – anxiety, fear
  • physiological - pain, fever, hypoglycaemia, injury, fluid deprivation, heavy exercise, etc.
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4
Q

stress response system of SNS

A

intergrated response

  • ↑ cardiac output and ventilation
  • Diversion of blood flow to muscles and heart
  • Mobilisation of glycogen and fat stores

“fight or flight”

synergistic with CRH-ACTH-cortisol

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5
Q

stress response system of CRH-ACTH-cortisol

A
  • Shift from protein & fat stores in favour of expanded glycogen stores and plasma glucose availability
  • Amino acids available for tissue repair if physical damage

cortisol has permissive action on adrenaline and noradrenaline

synergistic with SNS & adrenaline

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6
Q

stress response system of RAS, ADH, GH

A

decreased thyroid hormones

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7
Q

how does cortisol have a protective function in stress activated immune responses

A

cortisol has an anti inflammatory effect to prevent over activation of immune defence mechanisms

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8
Q
A
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9
Q

effects of chronic stress with prolonged elevated cortisol levels (4)

A
  • muscle wasting
  • hyperglycaemia
  • GI ulcers (increased susceptibility) : decreased production of prostaglandins in gut, responsible for mucus secretion that protect from gastric acid secretions - less protection
  • impaired immune response
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10
Q

what is cushing’s syndrome?

A

excess glucocorticoid activity

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11
Q

what is cushing’s disease?

A

ACTH- secreting anterior pituitary tumour

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12
Q

cushing’s syndrome

A
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13
Q

why are both ACTH and cortisol levels high in an ectopic tumour of ACTH- producing cells

A

ectopic tumour cells lack feedback mechanism

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14
Q

why do ACTH levels stay high in cushing’s syndrome?

A

tumour cells have impaired responsiveness to negative feedback from high cortisol levels

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15
Q

what are the levels of CRH in cushing’s syndrome and why?

A

decreased due to negative feedback from increased ACTH levels

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16
Q

what are signs and symptoms of cushing’s syndrome?

A
  • altered fat distribution- truncal obesity, buffalo hump, red round face
  • excess adrenal androgens - acne, female frontal balding and hirtuism, menstrual irregularities, testicular atrophy
  • breakdown of protein, muscle wasting, loss of collagen- thin arms and legs, muscle weakness, thin skin, purple striae
  • immunosuppressant- poor wound healing, easy bruising, infections
  • mental changes- cognitive difficulties, emotional instability, depression, sleep disturbances
  • altered bone metabolism- osteoporosis
  • hypertension (excess mineralocorticoid actiivty- sodium retention hypokalemia)
  • diabetes
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17
Q

what is cushing syndrome’s effect on parathyroid hormone?

A

increased secretion due to decreased bone formation, intestinal calcium formation and increased urinary calcium excretion

18
Q

what does excess glucocorticoids in childhood cause?

A

growth retardation

19
Q

what is the diagnosis of cushing’s syndrome?

A

elevated plasma cortisol levels confirm diagnosis

loss of diurnal cortisol rhythm

  • 24h urine free cortisol
  • ACTH measurements
  • dynamic tests- dexamethasone and CRH tests
20
Q

explain the diagnosis of CS using DEX tests

A
  1. Low dose: confirms cushing’s syndrome (cortisol remains high or in normal range suggests CS as low dose should cause suppression)
  2. 2nd test High dose test to confirm the cause of cushing’s syndrome
    1. Cushing’ disease low cortisol (supression of ACTH)
    2. Adrenal gland tumour low ACTH and high/ normal cortisol
    3. Ectopic ACTH tumour- high ACTH and high/ normal cortisol
21
Q

what are the cortisol levels of serum cortisol 9am, midnight and 24h urine cortisol tests in CS?

A

serum 9am: N or increased

serum midnight: increased

24h urine: increased

22
Q

what is CRH stimulation test used for?

A

determine pituitary- dependent Cushing’s and ectopic source of ACTH

in adrenal or ectopic ACTH syndrome- no response to CRH- cortisol and ACTH levels are flat

pituitary- dependent: N or increased cortisol

23
Q

how would you locate these tumours?

  1. ant pituitary
  2. adrenal
  3. bronchial
  4. ACTH secreting tumour
A
  1. MRI
  2. abdominal x ray
  3. chest x ray
  4. octrescan
24
Q

what are some treatments of cushing’s syndrome?

A

surgery or radiotherapy

drugs to inhibit steroidogenesis (pre-operative or pallative, not long term therapy)

25
Q

what is Conn’s syndrome?

what is the common cause?

A

primary hyperaldosteronism

tumour

26
Q

what are the clinical findings of conn’s syndrome?

A

hypokalemia and weakness

chronic hypokalemia- rena; dysfunction-> polyuria

hypertension is main clinical finding

27
Q

what is the treatment of Conn’s syndrome?

A

surgery, aldosterone receptor antagonist e.g. spironolactone

28
Q

what is addison’s disease?

what type of condition is this?

A

primary adrenal insufficiency

(apparent when 90% of adrenal cortex is destroyed)

rare and chronic condition- failure of adrenal glands

29
Q

What are some causes of destruction of adrenal tissue in Addison’s?

A

autoimmune, HIV or TB

30
Q

what are the levels of alosterone, cortisol, androgens and ACTH in Addison’s?

A

low except high ACTH due to minimal negative feedback loops

31
Q

what are some symptoms of Addison’s?

A
  • postural hypotension
  • muscle weakness, fatigue, lethargy
  • hyponatraemia, hyperkalaemia
  • increased pigmentation
    • ACTH production increased, and MSH melanocyte stimulating hormone: share same POMC precursor as ACTH
    • Increased melanin content in skin
    • Hyperpigmentation in skin creases, old scars, gums and inside of the cheek
  • weight loss, anorexia
  • nausea and vomitting
32
Q

what are some tests of addison’s/ adrenal failure?

A
  • cortisol (decreased) and ACTH levels (increased)
  • ACTH stimulation test
  • adrenal auto-antibodies (if suspect auto-immune disease)
33
Q

treatment of addison’s

A

life- long hormone replacement

Glucocorticoid hydrocortisone to mimic diurnal variation (two doses, AM and PM)

Mineralocorticoid fludrocortisone (daily)

Higher doses of glucocorticoids during times of illness or major stress (e.g. surgery)

34
Q

what is secondary adrenal insufficiency?

what are the clinical findings?

A

lack of ACTH production

low cortisol, normal aldosterone (RAAS intact)

35
Q

what are the causes of adrenal insufficiency?

A
  1. tumour, damage to pituitary
  2. secondary adrenal suppression-> exogenous glucocorticoid use
    - supression of ACTH levels-> supression atrophy of adrenal cortex
36
Q

when should you suspect excess glucocorticoid use?

A

cushingoid apperance

37
Q

what happens if there is a sudden withdrawal of glucocorticoid use?

A

symptoms of acute adrenal insufficiency - lack of cortisol activity (weight loss, fatigue, N&V)

38
Q

what is an adrenal crisis?

A

= Acute adrenal insufficiency expressed when patient is under stress (e.g. infection)

→ hypotension, circulatory failure, death

Urgent treatment (iv fluids, hydrocortisone, (iv then oral))

medical emergency

39
Q

what is congenital adrenal hyperplasia?

A

inherited defect in an enzyme involved in the production of cortisol and aldosterone

>90% of CAH due to deficiency of 21β-hydroxylase

40
Q

what happens in severe and less severe cases of CAH?

A

severe: females born with ambiguous genitalia- incorrect gender assignment

less severe: children- precocious puberty

females: virilisation (male characteristics)

41
Q

what are some clinical findings of CAH?

A

low cortisol and aldosterone

build up of androgens

decreased negative feedback inhibition-> excess ACTH

Prolonged ACTH hyperstimulation results in hyperplasia of the adrenals

42
Q

treatment of CAH

A

hormone replacement

plastic surgery (androgens)

Medicine 3 (31 decks)

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