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Year 5 Path Chemical Pathology > Year 2: Adrenals > Flashcards

Year 2: Adrenals Flashcards

1
Q

What is cushings syndrome?

A

High ACTH

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2
Q

What is Cushing’s disease?

A

High ACTH because of pituitary signaling (secondary hyper cortisol)

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3
Q

Recall the symptoms of cushing’s syndrome

A
  • central Weight gain
  • Muscle weakness
  • Moon face
  • Proximal myopathy
  • Think skinn
  • poor would healing
  • easy bruising
  • hypertension
  • osteoporosis
  • Type 2 Diabetis
  • peripheral pitting oedema
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4
Q

What are the causes of Cushing’s syndrome?

A

Most common:

  • Taking too many steroids

But also:

  • Pituitary dependent Cushing’s disease
  • Ectopic ACTH from lung cancer
  • adrenal adenoma secreting cortisol
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5
Q

Which investigations would you perform to determine cushing’s syndrome?

A
  • 24 h urine collection for urinary free cortisol
  • Blood diurnal cortisol levels (changes over day)
  • (cortisols usually highest at 9am and lowest at midnight, if asleep)
    • –> need to get a mid-night sample without people telling it to diagnose
  • Basal (9am) cortisol 800 nM

But also

  • Low dose dexamethasone suppression test
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6
Q

Explain the prosess and interpretation of a low dose dexamethasone supression test

A

Dexamethasone is a artificial steroid

administerd over 48 h, 0.5mg/6h

Physiologically:

  • cortisol production will be supressed to 0
  • In Cushing’s: production will not be supressed!(

•End of LDDST: 680 nM

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7
Q

How do you determine the cause of cushings?

A

Dexamethasone supression test

  • ACTH morning (e.g. if low: not ectopic or adrenal adenoma)
  • supression of cortisol due to dexamethasone –> if it does not happen + ACTH low –> cushings

24h urine free cortisole

Midnight blood cortisol levels

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8
Q

How can you treat cushing’s?

A

Remove the cause e.g. Surgery in tumor (pituitary, adrenalectomy (bilateral, unilateral)

But also Medication:

·Inhibitors of steroid biosynthesis:

  • metyrapone;
  • ketoconazole
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9
Q

Explain the Mechanism of action and use of METYRAPONE

A

Anti-steriod drug to treat Cushings:

  • inhibits 11ß-hydroxylase

Use:

1) Prior to surgery

  • adjust dose (oral) according to cortisol (aim for mean serum cortisol 150-300 nmol/L)
  • –>improves patient’s symptoms and promotes better post-op recovery (better wound healing, less infection etc)

2) Control of Cushing’s symptoms after radiotherapy (which is usually slow to take effect)

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10
Q

What are the side effect of Metyrapone

Explain them

A

11ß-hydroxylase inhibitor leading to

  1. Accumulation of deoxycorticosterone –> has aldosterone-like effects
    • hyertension due to more water and salt retention
  2. More accumulation of

17α-hydroxyprogesterone –> can be converted into testosterone –> higher androgen levels

* Hirsutism in women (männlicher Behaarungstyp bei Frauen)
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11
Q

Explain the use and mechanism of action of Ketoconazol

Side-effect

A

Off-label use in (14-α-sterol demethylase (a cytochrome P-450 inhibitor) inhibits synthesis of lanosterol to ergosterol

Cushing’s syndrome

    • treatment and control of symptoms prior to surgery
  • orally active

Side effects:

  • ·Liver damage - possibly fatal - monitor liver function weekly, clinically and biochemically
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12
Q

What is Conn’s syndrome?

A
  • Benign adrenal cortical tumour (zona glomerulosa)
  • Aldosterone in excess

–> increased salt+ water retention

–> Hypertension and hypokalaemia

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13
Q

How do you diagnose Conn’s syndrome?

A

Measure Hormone:

  • Primary hyperaldosteronism (if high)

Measure Renin:

  • Renin - angiotensin system should be suppressed (to exclude secondary hyperaldosteronism) –> Renin should be low
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14
Q

How do you treat Conn’s syndrome?

Explain the mechanisms of action of the pharmacological treatment including side effects

A
  1. SPIRONOLACTONE
    • Converted into canrenone which is a
    • ​mineralocorticoid receptor (MR) antagonist
    • –> reduced Na+ reabsorbtion and K+ excretion
      • Side effects:

·Menstrual irregularities (+ progesterone receptor)

·Gynaecomastia (- androgen receptor)

  1. EPLERONONE
    • also MR antagonist
    • but more specific: (·Less binding to androgen and progesterone receptors compared to spironolactone, so better tolerated)

Also possible:

Surgery

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15
Q

What are Phaeochromocytomas?

A

The are very rare

  • tumours of the adrenal MEDULLA which secrete catecholamines –> Adrenaline, Noradrenaline

*

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16
Q

What are the symptoms of Phaeochromocytomas?

A
  • Hypertension in young people
  • Episodic severe hypertension (after abdominal palpation)
  • More common in certain inherited conditions
  • Also other symptoms like increased agression, tachycardia, dilated pupils, sweating, headache etc.

One attack can lead to death!

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17
Q

What is so problematic about Paeochromocytomas?

A
  • Severe hypertension can cause myocardial infarction or stroke
  • High adrenaline can cause ventricular fibrillation + death

–> One attack can be deadly

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18
Q

How do you treat Paeochromocytomas?

A

(Carefull) surgery (might lead to hypertensive crisis)

Pharma:

  1. Alpha Blockage (together with IV fluid to prevent hyptension)
  2. ß Blockage added (to prevent tachycardia)
19
Q

Where (in which tissues) do Paeochromocytomas normally occur?

what are their characteristics?

A

They are extremely rare!

  • •10 % extra-adrenal (sympathetic chain)
  • •10 % malignant
  • •10 % bilateral
  • 25% genetic
20
Q

Explain and summarise the synthesis of adrenocortical hormones

A
21
Q

What are the causes for adrenocortical failure?

A

Aquired:

  • Tuberculous Addisons disease due to TB (commoneset world wide)
  • Autoimmune addisons disease (commonest in UK
  • cancer

Congenital

  • lack of enzymes for synthesis
22
Q

What is vitiligo?

What does this tell you?

A

It is the destruction of Melanocytes showing in white spots

–> people are more prone to autoimmune disease

23
Q

What are the signs and symptoms of aquired Addison’s disease?

A

Loss of Aldosterone:

  • increase plasma K+ (no K+ excretion due to lack of Aldosterone)
  • postrual hypotension
  • hyponatremia

Lack of Cortisol:

  • weight loss
  • exhaustion
  • anorexia, vomiting, diarreah
  • tanning
  • hypoglycaemia
24
Q

What happens in an addisonian crisis?

A

Severe hypotenstion

hyponatraemia

hypoglycaemia

hyperkalaemia

vomiting + diareah resulting in dehydreation

–> cunfusion, extreme tiredness,

–> potentially fatal !

25
Q

If you suspected someone to have Addisons disease: what tests would you perform?

What do you expect?

A

Tests:

  • 9am Cortisol levels –> low
  • ACTH –> high

Also:

  • short synACTHen test
  • –> IM dose if synthetic ACTH –> expect someone to increase its cortisol production
  • –> if there is none= Addisons
26
Q

Which condition do you have to think of when somoene presents with hyponatraemia and hyperkalaemia?

A

Addisons disease

27
Q

What are the causes for congenital adrenal hyperplasia?

A

Deficiency of enzymes

  • 95% of cases: 21 hydroxylase deficiency
  • Can be complete or partial

–> Deficiency of enzyme lead to the fact that no Cortisol/ Aldosterone can be produced

28
Q

Regarding complete 21 hydroxilase deficiency:

Which hormones will be totally absent ?

How long can you survive ?

Which hormones will be in excess?

A

Cortisol and Aldosterone will be totally absent

–> can only survive for less than 24h

BUT: excess sex steroids (mainly testosterone) due to higher concentration of educt

29
Q

What are the symptoms of complete 21-dehydroxylase deficiency?

When would someone present with symptoms?

A

Presenting as a neonate with a salt losing Addisonian crisis (within 24h after birth)

Because:

  • Before birth, (while in utero), foetus gets steroids across placenta
  • Girls might have ambiguous genitalia (virilised by adrenal testo)
30
Q

What are the symptoms of a partial 21-hydroxylase deficiency?

A

Cortisol and Aldosterone deficiency but excess sex hormones

Will present at any age as they will survive

BUT:

In Girls: Hirtuism and Verilisation is a problem (due to excess testosterone)

In Boys: early puberty is problem (due to raised testosterone)

31
Q

What are the characteriostics of 11 deoxycorticosterone?

A

It behaves like aldosterone

–> Someone with 11 hydroxylase defect only presents with symptoms of low Cortisol, not with low aldosterone (in fact opposite leading to hypokalaemia) because 11 deoxycarticosterone binds to MR on Kidney

32
Q

How does a 21 hydroxilase deficiency lead to an adrenal hyerplasia?

A

Because:

  • high ACTH will stimmulate growth of adrenals
33
Q

What would the appropriate treatment in primary adrenocortical failure?

A

Addisons disease: lack of Cortisol and Aldosterone

Oral replacement of steroids :

  1. Hydrocortisone (Sometimes Prednisolone) –> cortisol replacement
  2. Fludrocortisone –> aldosterone replacement
34
Q

How would you treat secondary Adrenocortical failure?

A

Basically an ACTH deficiency

Because Aldosterone is not controlled by ACTH: only lack of Cortisol

  • Treated by oral replacement of Hydrocortisone
35
Q

How would you treat someone with severe (postural) hypotension, confusion, low Na+, high K+, confusion?

A

All signs for Addisonian crisis –> is a medical emergency, can’t wait for test

  1. IV 0.9% NaCl
  2. High dose of Hydrocortisone –> replaces both: Cortisol and Aldosterone because 11ß-HSD can’t “protect” kidney from it at these high concentrations
  3. If hypoclycaemic: 5% dextrose
36
Q

How would you treat Congenital adrenal hyperplasia (CAH)?

How do you measure if you got the dosage right?

A

95% lack 21-hydroxylase –> mostly only partial lack –> will still make some aldosterone + cortisol but:

Main complaint is the high sex steroid production (because of high ACTH)

  • can be reduced via high dosages of Dexamethasone, Hydrocortisone (-ve feedback on ACHT production)
  • BUT: if too high cortisone replacements: cushings
  • Aimed for normal 17 OH progesterone levels

–> Difficut to fing right balance

37
Q

What is important to tell someone if they are on oral cortisol replacement?

A

Cortisol is a stress hormone that fluctuates physiologically

  • normal levels =20mg/day
  • in sickness/injury = 200-300 mg/day

–> improtant in wound healing and immune system

Someone on replacement: Need to match dosage to illness/streee of body

  • Eg. at minor illness (cold etc) –> double the dosage
  • Before and after surgery (also to help with anesthetics) until be able to eat alone
38
Q

How can you distinguish cushings disease from ectopic ACTH?

A

With a high dose dexamthasone supression test:

  1. In Cushings disesase: high dose will evoke negative feedback on pituitary cells that produce ACTH–> low ACTH in cushings
  2. In Ectopic: ACTH will still be high
39
Q

What different drugs are available for replacement of adrenal steroids?

What are their characteristics?

A
  1. Hydrocortisone
    • Glucocorticoid with affinity for MR at high doses
    • t1/2= 8h
  2. Prednisolone
    • Glucocorticoid with weak MR affinity
    • t1/2= 12h
  3. Dexamethasone
    • Glococorticoid with no MR affinity
    • t1/2= 40h
  4. Fludrocortisone
    • Aldosterone analogue
40
Q

Where are Mineralcorticoid receptors distributed?

What is their affinity?

A

Not selective for Cortisol/Mineralcorticoids

  • only found in Kidney (/+brain)
  • high affinity for cortisol
41
Q

Where are Glucocorticoid receptors found?

What is their selectivity/affinity?

A
  • lWide distribution
  • lSelective for glucocorticoids
  • lLow affinity for cortisol
42
Q

How are some tissues (i.e. kidney) protected from cortisol?

A

They are protected via 11ß-hydroxysteroid dehydrogenase –> protectes the MR

that turns

Cortisol –> Cortisone (inactive)

43
Q

What are the possible routes of administration of adrenal hormone replacement?

A

All hormones can be given orally

  • Hydrocortisone
  • Dexamethasone
    • IV/IM administration is possible

Year 5 Path Chemical Pathology (24 decks)

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