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Endocrine > HPA axis > Flashcards

HPA axis Flashcards

1
Q

What are the 3 layers of the adrenal gland?

A

Capsule
Cortex
Medulla

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2
Q

What are the layers of the adrenal cortex?

A

Zona glomerulosa
Zona fasciculata
Zona reticularis

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3
Q

What is produed in the zona glomerulosa?

A

Mineralocorticoids- aldosterone/ progesterone

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4
Q

What is produced in the zona fasciculata?

A

Corticosteroids - cortisold
small amounts of androgens

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5
Q

What is produced in the zona reticularis?

A

Androgens eg DHEA and small amount of corticosteroids

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6
Q

What is the venous and arterial supply of the adrenal glands?

A

Venous:
R: inf. vena cava
L: l renal vein

Arterial:
Sup, mid, inf adrenal artery

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7
Q

What is produced in the adrenal medulla?

A

Chromaffin cells produce catecholamines, epinephrine, norepinephrine

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8
Q

Describe the HPA axis

A

Hypothalamus -> CRH (corticotropin releasing hormone)
Ant. pit -> ACTH (adrenocorticotropin hormone)
Cortex of adrenal gland -> glucocorticoids (androgens and cortisol)

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9
Q

What are the normal physiological actions of cortisol?

A

Gluconeogenesis
Lipolysis in adipose tissue
Protein and fat metabolism
Anti-inflam
Immunosupression

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10
Q

What are the actions of glucocorticoids?

A

affect carc, fat, protein metabolism `

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11
Q

What are the actions of mineralocorticoids?

A

control sodium and potassium balance (aldosterone)

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12
Q

What is the action of CRF?

A

Corticotropin releasing factor acts on ant pit -> ACTH to act on adrenal cortex to release androens and cortisol

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13
Q

What type of hormones does the adrenal cortex produce

A

steroid hormones

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14
Q

What is Cushing’s syndrome?

A

Abnormal persistent elevated glucocorticoid levels with loss of circadian cortisol secretion and loss of normal negative feedback

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15
Q

What is Cushing’s disease?

A

Pituitary adenoma causing excessive ACTH secretion causing bilateral adrenal hyperplasia causing excessive cortisol production

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16
Q

What are the ACTH dependent causes of cushings syndrome?

A
  1. Cushing’s disease - pit adenoma
  2. Ectopic ACTH production eg small cell lung cancer and carcinoids
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17
Q

What are the ACTH independent causes of Cushing’s syndrome?

A

Adrenal carcinoma
Iatrogenic - steroid use

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18
Q

What are the signs for Cushing’s syndrome?

A

Round moon face
Central obesity
Back buffalo hump
Purple abdo striae
Hyperglycaemia/ hypertension/ osteoporosis
Thin skin

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19
Q

What are the symptoms for Cushing’s syndrome?

A

Weight gain
Acne
Peripheral weakness
Mood change- irritable/ depression/ psychosis
Gonadal dysfunction- erectile dysfunction/ irregular periods

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20
Q

What is the men to women prevalence of cushing disease?

A

equal

21
Q

What age do people usually present with Cushing’s?

A

30-50 yrs

22
Q

What is the main investigation for Cushing syndrome?

A

dexamethasone suppression test

23
Q

How is dexamethasone used to diagnose Cushings

A

Acts as glucocorticoid steroid to suppress ACTH production
Sees if cortisol production is reduced

24
Q

What are the results for the first line dexamethasone test for Cushings?

A

Suppressed ACTH and high cortisol with low dose (1mg) of dexa.
Given at night, measured in the morning

25
Q

What are the results for the second dexamethasone test for cushing’s?

A

Cushing’s disease = suppressed ACTH and cortisol
Ectopic ACTH = high ACTH and cortisol
Adrenal adenoma = suppressed ACTH and high cortisol

26
Q

What is the treatment for iatrogenic Cushing’s syndrome ?

A

stop medication

27
Q

What is the treatment for Cushing’s disease

A

Pituitary adenoma removal

28
Q

What is the treatment for Cushing’s syndrome caused by ectopic ACTH?

A

Surgery

29
Q

What is the treatment for Cushing’s syndrome caused by adrenal adenoma?

A

Adrenalectomy (nelsons syndrome as a complication)

30
Q

What are the conditions for the dexamethasone suppression test?

A

Overnight 12am given then 8am measurement

31
Q

What is primary adrenal insufficiency?

A

Destruction of the adrenal cortex resulting in deficiency in mineralocorticoids, glucocorticoids and androgens

32
Q

What is Addison’s disease?

A

Primary adrenal insufficiency caused by autoimmune destruction of the adrenal cortex resulting in deficiency of mineralocorticoids, glucocorticoids and androgens

33
Q

Describe the pathophysiology of Addison’s disease

A

Autoimmune destruction of adrenal cortex by 21-hydroxylase adrenal autoantibodies

34
Q

What are the ACTH levels in Addisons and why and what symptom does this cause?

A

High due to low cortisol levels which results in negative feedback to pit gland
causes hyperpigmentation

35
Q

Describe the epidemiology of Addison’s

A

Rare- 0.8/100,000
More common in women

36
Q

What is the main cause of primary adrenal insufficiency in the UK

A

Addisons disease

37
Q

What is the main cause of primary adrenal insufficiency worldwide?

A

TB

38
Q

Describe the clinical presentation of Addison’s disease

A

Fatigue
Tanned
Hyperpigmentation- palmar, sun-exposed areas, waist
GI: wt loss, abdo pain, nausea, vomiting, loss appetite
CVS: postural hypotension, hypoglycaemia
MSK: joint pain, muscle cramps
Depressed/ anxious/ psychosis

Tanned, Tearful, Tired, Toned,

39
Q

What are the investigations and results for Addison’s disease?

A

ACTH stimulation test: low cortisol
U&E: High K+ and low Na+ (lack aldosterone)
Serum ACTH: High ACTH and low cortisol= primary
Low ACTH and cortisol = secondary
21-hydroxylase adrenal autoantibodies positive

40
Q

What is the ACTH stimulation test and what is it used for?

A

Used to diagnose Addison’s disease
Measure baseline cortisol
Give ACTH and measure cortisol 30 min after
Addisons= low cortisol (adrenal destruction)

41
Q

What is the managment of Addison’s?

A

Oral hydrocortisone to replace steroids
Fludrocorticosone to replace aldosterone

42
Q

What are the Na and K ion levels for Addison’s disease and why?

A

Low Na+ and high K+ due to lack of aldosterone

43
Q

What are the complications of Addison’s disease?

A

Adrenal crisis
- life threatening

44
Q

What are the symptoms of an adrenal crisis?

A

Reduced conciousness
Hypoglycaemia, hypotension

45
Q

What is the management for an adrenal crisis?

A

Immediate treatment
IV fluids
Steroids
Glucose
Intensive monitoring

46
Q

What is secondary adrenal insufficiency?

A

Lack of ACTH production from the pit gland causing deficiency in cortisol

47
Q

What is the common cause in secondary adrenal insufficiency?

A

Iatrogenic- long term steroid use disturbs the pit. adrenal axis

48
Q

How is primary adrenal insufficiency different to hypothalamic-pituitary disease?

A

Deficiency in mineralocorticoids which aren’t controlled by the pituitary

Endocrine (7 decks)

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