Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Phase 2 3. Endocrinology > Disorders of the human adrenal gland > Flashcards

Disorders of the human adrenal gland Flashcards

1
Q

What is adrenal insufficiency?

A

Inadequate adrenocortical function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What causes primary adrenal insufficiency?

A

o Addison’s disease
o Adrenal TB/malignancy
o Congenital Adrenal Hyperplasia (CAH) = neonatal form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What can cause secondary adrenal insufficiency?

A

Due to lack of ACTH stimulation of the adrenal glands

  • Iatrogenic (excess administration of exogenous steroid)
  • Pituitary/hypothalamic disorders
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What causes congenital adrenal hyperplasia?

A

genetic disease:
- autosomal recessive

= lack of 21-hydroxylase activity

= deficiency of cortisol and aldosterone

= increased adrenal androgens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the significance of lack of 21-hydroxylase activity?

A

most important enzyme in aldosterone and cortisol production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do boys present with CAH?

A

adrenal insufficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do girls present with CAH?

A

masculinisation of female genitalia due to

excess exposure to androgens in utero

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Addison’s disease?

A

Autoimmune destruction of adrenal cortex

o >90% destroyed before symptomatic
o Autoantibodies positive in 70%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the clinical features of Addison’s disease?

A 
Non-specific symptoms
o Anorexia, weight loss
o Fatigue/lethargy
o Dizziness and low BP
o Abdominal pain, vomiting, diarrhoea
o Skin pigmentation (should not be missed!) on palmar creases and buccal mucosa

Symptoms are often precipitated by an intercurrent illness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What tests are used to diagnose adrenal insufficiency?

A
  • electrolyte derrangement
  • Short synacthen test
  • High ACTH levels
  • high renin
  • low aldosterone
  • adrenal autoantibodies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe biochemistry results in adrenal insufficiency

A

marked electrolyte derangement

  • Low Na
  • High K
  • hypoglycaemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the short synacthen test

A

SYNACTHEN = synthetic ACTH

  • Stimulate cortisol
  • Measure plasma cortisol before and 30 minutes
    after IV ACTH injection

Normal: baseline >250nmol/L, post ACTH >;480

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the ACTH levels in adrenal insufficiency

A

Increased

  • Pituitary attempts to stimulate cortisol production
  • This is what causes skin pigmentation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the renin levels in adrenal insufficiency

A

Raised renin because of stimulation by RAAS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the aldosterone levels in adrenal insufficiency

A

low

- causes hyperkalaemia and hyponatraemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is adrenal insufficency treated?

A
  • Hydrocortisone as cortisol replacement

- Fludrocortisone as aldosterone replacement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Why is hydrocortisone used in adrenal insufficency?

A

Metabolised to cortisol. Most physiological way of replacing cortisol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe treatment pattern of hydrocortisone in adrenal insufficiency

A

If unwell, give intravenously first

o Then 15-30mg oral tablets daily in divided doses (for long-term maintenance)
o Try to mimic diurnal rhythm

 Highest levels in the morning, therefore give higher dose in the morning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the significance of adrenal insufficiency

A
  • untreated = fatal
    (Do not delay treatment to confirm diagnosis)

‘sick day rules’ – double oral hydrocortisone for 3 days when unwell

o Cannot stop suddenly, as this will cause adrenal crisis
o Need to wear identification

20
Q

What are the main causes of secondary adrenal insufficiency?

A

(LACK OF CRH/ACTH)

  • pituitary/hypothalamic disease (tumour, surgery, radiotherapy)
  • exogenous steroid use
21
Q

How does exogenous steroid use cause secondary adrenal insufficiency?

A

Commonest cause
o Risk for patients on exogenous steroids for
> 6 weeks (possibly even >3 weeks)
o Negative feedback of endogenous steroids
on CRH/ACTH

22
Q

What are the clinical features of secondary adrenal insufficiency?

A

similar to Addison’s EXCEPT:
o Skin pale (no  ACTH, therefore no pigmentation)
o No electrolyte abnormalities as aldosterone production is intact (regulated by RAAS)

23
Q

How is secondary adrenal insufficiency treated?

A

hydrocortisone replacement

24
Q

What is Cushing’s syndrome?

A

Excess cortisol secretion

25
Q

What are the clinical features of Cushing’s syndrome?

A

cortisol excess:

  • Centripetal obesity
  • Thin bones
  • Prone to HTN/hyperglycaemia
26
Q

What are non-specific symptoms of cushing’s?

A

 Easy bruising (thin skin)
 Facial plethora
 Striae
 Proximal myopathy

27
Q

What are the types of cushing’s?

A
  • ACTH dependent

- ACTH independent

28
Q

What are the causes of ACTH dependent Cushing’s?

A

o Pituitary adenoma (68%) Cushing’s Disease (cushing’s
syndrome caused by a pituitary adenoma)
(most common cause of endogenous)

o Ectopic ACTH 12% (carcinoid/carcinoma)
o Ectopic CRH <1%

29
Q

What are the causes of ACTH independent cushing’s?

A

o Adrenal adenoma (benign) 10%
o Adrenal carcinoma (malignant) 8%
o Nodular hyperplasia 1%

30
Q

What steps do you need to take to diagnose Cushing’s?

A
  • establish cortisol excess

- determine underlying cause

31
Q

How can you determine cortisol excess?

A
  • Dexamethasone suppression testing
    (V. good screening test)
  • 24-hour urinary free cortisol
    (more accurate due to diurnal rhythm)
  • Late night salivary cortisol
    (Should be almost undetectable)
32
Q

How do you determine the underlying cause of Cushing’s?

A
  • ACTH dependent or independent?
- If ACTH is low, it must be a problem with the
adrenal gland (ACTH-independent)
  • If ACTH is high, it must be ACTH dependent
    Cushing’s
33
Q

How is Cushing’s managed?

A

Surgical
o Transphenoidal pituitary surgery
o Laparoscopic adrenalectomy
o Removal of ACTH source

Medical
o Metyrapone/ketoconazole
o Inhibit cortisol production, but not very well
tolerated
o Short term measure
34
Q

What is IATROGENIC CUSHING’S SYNDROME?

A

Cushingoid appearance but low plasma cortisol

35
Q

What causes iatrogenic Cushing’s syndrome?

A

prolonged high dose steroid therapy

(e. g. asthma, rheumatoid arthritis, inflammatory bowel disease, transplants)
- Steroid therapy for these conditions is usually higher than physiological levels of cortisol
- Usually oral therapy
- Can occur with high dose inhaled steroids or steroid injections

Chronic suppression of pituitary ACTH production and adrenal atrophy

36
Q

What is the pathophysiology of adrenal suppression?

A

Long term steroid treatment suppresses ACTH production (negative feedback to anterior pituitary)

Atrophy of adrenal cortex

37
Q

What are the implications of steroid dependent patients?

A

Patients become steroid dependent. Implications:
o Unable to respond to stress (illness/surgery)
o Need extra doses of steroid when ill/surgical procedure
o Cannot stop suddenly
o Gradual withdrawal of steroid therapy if >;4-6 weeks

38
Q

What is PRIMARY ALDOSTERONISM (CONN’S SYNDROME)?

A

Autonomous production of aldosterone independent of its regulators (angiotensin II/potassium)

39
Q

What causes primary aldosteronism?

A

single adrenal adenoma or bilateral adrenal nodules

40
Q

What are the clinical features of primary aldosteronism?

A

o Significant hypertension
o Hypokalaemia (in up to 50%)
o Alkalosis

41
Q

How is Primary Aldosteronism diagnosed?

A
  • Biochemistry
    o Plasma aldosterone elevated
    o Plasma renin concentration suppressed
  • Suppression testing
    o Intravenous saline load => should switch off RAAS
  • Adrenal CT scan to identify single lump/bilateral nodules
42
Q

What are the treatment options of primary aldosteronism

A 
Surgical
o Unilateral laparoscopic adrenalectomy
o Only if adrenal adenoma
o Cure of hypokalaemia
o Cures hypertension in 30-70% cases

Medical
o In bilateral adrenal hyperplasia
o Use MR antagonists (spironolactone or eplerenone)
o Or amiloride (blocks Na reabsorption by kidney – blocks ENaC, therefore blocks effect of
aldosterone)

43
Q

What is PHAEOCHROMOCYTOMA?

A

Catecholamine secreting tumours of the adrenal medulla

44
Q

What are the symptoms of phaeochromocytoma?

A

Hypertension (intermittent in 50%)

Hallmark symptoms: episodes of headache, palpitations, pallor and sweating

45
Q

How is phaeochromocytoma diagnosed?

A

Measure 24 hour urinary catecholamines and metabolites (metanephrin and normetanephrin)

CT scan of adrenals

46
Q

How is phaeochromocytoma treated?

A

Adrenalectomy is treatment of choice
o Need pre-operative treatment with α1 +/- β1 antagonists to block effects of catecholamine surge
o Can become haemodynamically unstable in surgery if this is not done

Phase 2 3. Endocrinology (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions