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chemical pathology > Adrenal Disease > Flashcards

Adrenal Disease Flashcards

1
Q

Adrenal Microanatomy

A
  • Capsule
  • Glomerulosa – produces mineralocorticoids
  • Fasciculata – produces glucocorticoids
  • Reticularis- produces sex steroids
  • Medulla

“The deeper you go, the sweeter it gets”

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2
Q

Adrenal anatomy

A

has only 1 central vein and 57 adrenal arteries

  • The left adrenal drains into the left renal vein
  • The right adrenal drains directly into the IVC

To measure adrenal output, a cannula is placed through the IVC and into the adrenal vein

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3
Q
  • 31-year-old presents with profound tiredness
  • Acutely unwell a few days
  • Vomiting

Data

  • Na: 125, K: 6.5, U: 10, Glucose: 2.9mM
  • FT4 < 5nM, TSH >50mU/L
A

low Na, high potassium, low glucose

hyponatraemia + hyperkalaemia = deficiency of mineralocorticoid - aldosterone

hypoglycaemia: deficiency of glucocorticoid- cortisol

ADDISON’S DISEASE

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4
Q

define Addison’s disease

A

Addison’s disease = adrenal insufficiency

Deficiency of mineralocorticoid and glucocorticoid

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5
Q

common causes of Addison’s disease (developed and developing countries)

A

autoimmune disease (developed countries

Tuberculosis of adrenal glands (developing countries)

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6
Q

primary hypothyroidism + addison’s disease =

A

SHMIDT’S SYNDROME
PGAI (Polyglandular autoimmune syndrome) Type 2.

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7
Q

Tests for Addison’s disease

A

Synacthen test:

  • Measure cortisol + ACTH at the start of the test
  • Administer 250microgram synthetic ACTH by IM injection
  • Check cortisol at 30 and 60 minutes:

*If cortisol RISES A LOT = INTACT adrenals
*If cortisol does NOT rise= do NOT have intact adrenals

NOTE: Healthy people should produce > 550 nM of cortisol within 30 minutes

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8
Q
  • Results of short synacthen test:
    o ACTH > 100ng/dl – HIGH
    o Cortisol < 10nM at 30 mins – LOW
    o Cortisol < 10nM at 60 mins – LOW

What urgent treatment is needed?

A

results indicate adrenal insufficiency

Normal 0.9% Saline infusion over 1 hour and IV hydrocortisone

  • Need to rehydrate the dehydrated hypotensive patient + Give IV hydrocortisone at the same time as giving saline infusion
  • Saline should go first as it will work immediately
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9
Q

complications of addison’s disease

A

People die of hyperkalaemia – can lead to arrythmias AND/ OR hypotension and shock

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10
Q
  • 32 year old present with hypertension
  • He is noted to have an adrenal mass

What are the possible adrenal masses and describe there significance

A
  • Adrenal medullary tumour: Phaeochromocytoma: adrenaline secreting tumour = SUDDEN episodic rises in BP
  • Conn’s syndrome : secretes aldosterone: retention of sodium and loss of potassium
  • Cushing’s syndrome: secretes cortisol : Moon face, buffalo hump, thin shiny skin

These 3 ALL cause hypertension + hypokalaemia
(less so for phaeochromocytomas)

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11
Q

HIGH levels of urinary catecholamines indicates what

A

pheochromocytoma

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12
Q

management of pheochromocytoma

A
  • Fluids first as alpha blockade can decrease BP
  • Give alpha-blockade NEXT (e.g. phenoxybenzamine or doxazosin)
  • then beta blockade to prevent reflex tachycardia

-then later: Cure = surgical removal of tumour

So:

FABC

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13
Q

complications of pheochromocytoma

A

secretes huge amounts of adrenaline:

sudden severe hypertension, arrhythmias (VF) and sudden cardiac death

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14
Q
  • Genetic syndromes associated with Phaeochromocytoma
A

MEN 2, NF I, VHL syndrome

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15
Q
  • Hypertensive 33-year-old
  • Na: 147, K: 2.8, U: 4,0, Glucose: 4mM
  • Plasma aldosterone- RAISED
  • Plasma renin SUPPRESSED

what is the diagnosis:

A

Conn’s syndrome/ Primary hyperaldosteronism

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16
Q

what is Conn’s syndrome/ Primary hyperaldosteronism

A

adrenal gland secretes high levels of aldosterone autonomously =

hypernatraemia + hypokalaemia+ hypertension and this will in turn suppress the renin at the JGA

17
Q
  • 34-year-old obese woman with T2DM, presents with hypertension and bruising
  • Na: 146, K: 2.9, U: 4.0, Glucose 14.0
  • Aldosterone < 75 (LOW)
  • Renin LOW

What is the diagnosis

A
  • Cushing’s syndrome
18
Q

causes of Cushing’s syndrome

A
  • oral steroids (this is the most common)
  • Adrenal tumour producing cortisol without ACTH
  • Pituitary tumour producing ACTH: Pituitary dependent Cushing’s disease
  • Ectopic tumour producing ACTH: lung cancer
19
Q

Test for Cushing’s syndrome

Which dynamic test is needed to confirm Cushing’s?

A
  • 9am cortisol- elevated normally so will not help to distinguish
  • 12 midnight cortisol- suppressed normally but high in Cushing’s

definitive diagnosis = - Dexamethasone suppression test

20
Q

explain Dexamethasone suppression test

A

Dexamethasone is a VERY potent steroid
so will switch off ACTH normally + suppress cortisol to UNDETECTABLE LEVELS

In Cushing’s, there will NOT be suppression and it will keep on making the hormone

21
Q
  • MOST COMMON cause for Cushing’s syndrome
A

Being on oral steroids: becolmethasone inhalers etc

22
Q
  • An obese 35-year-old patient has the following results:
  • 9am cortisol (Monday): 650nM
  • Given 0.5mg dexamethasone every 6 hours for 48 hours- low dose dexamethasone suppression test
  • 9am cortisol (Wednesday) < 50nM

what is the diagnosis

A
  • Normal obese person: pseudo-Cushing’s syndrome

Obesity is a growing common reason now

Tell her she does not have any serious adrenal problem; she needs help for weigh loss

23
Q
  • 9am cortisol (Monday): 650nM
  • Given 0.5mg dexamethasone every 6 hours for 48 hours- low dose dexamethasone suppression test
  • 9am cortisol (Wednesday): 500nM NOT <50nM

what is the diagnosis

A
  • Cushing’s syndrome
24
Q

What is the next step once you have found cushing’s syndrome following low dose dexamethasone suppression test?

A

-Sampling from the pituitary (IPSS)

inferior petrosal sinus sampling

*measures ACTH levels in the veins near pituitary and compares them with the periphery- look at the gradient*

25
Q

why is high dose dexamethasone suppression test not useful

A

VERY INACCURATE (high false positive rate)

26
Q

Inferior Petrol sinus Sampling with CRH stimulation

A
  • Catheterise patient: needle in groin and into the cranial vessels and take blood and measure ACTH in the gland
  • Take blood from the right and left pituitary as well as a peripheral vein
  • Measure prolactin (to prove you are in the right place
  • Inject CRH and if there is a high rise in ACTH in either pituitary vein (but NOT peripheral), this proves that there is a pituitary source of ACTH

Will need surgery

27
Q

how to distinguish from pituitary dependent and ectopic causes of cushing’s

A

Inferior petrosal sinus sampling

a) if raised pituitary: peirpheral ACTH ratio –> PITUITARY DEPENDENT

–>ca follow up with pituitary MRI

b) if normal pituitary: peripheral ACTH ratio- EITHER i) adrenal tumour or ii) ectopic ACTH

–> adrenal CT/CT abdomen - adrenal tumour

–>CXR/CT thorax- ectopic ACTH

28
Q

Why is adrenal failure worse than pituitary failure?

A

Because at least in pituitary failure you still have aldosterone left

29
Q

How do you differentiate between primary and secondary adrenal insufficiency?

A

Long synacthen test

**cut off for cortisol is 900**

30
Q

Diagnosis of primary hyperaldosteronism

A

high aldosterone: renin ratio

31
Q

Diagnosis of phaeo

A

Plasma and 24h urinary metadrenaline measurement/ catecholamines & VMA

**raised

32
Q

If you have hypertension, high sodium and low potassium with raised renin and aldosterone what is it?

A

secondary hyperadrenalism

i.e renal artery stenosis

33
Q

Tx of cushing’s

A

KM -karim meeran

Ketoconazole and metyrapone

chemical pathology (22 decks)

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