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Semester 2 - MEH > 20. Adrenal disorders > Flashcards

20. Adrenal disorders Flashcards

1
Q

What are the clinical presentation of adrenal hormone deficiencies?

A

• Cortisol: ACTH excess from pituitary
weakness, tiredness, weight loss, hypoglycaemia

  • Mineralocorticoid: dizziness, low Na, high K
  • Androgen: low libido and loss of body hair in women
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2
Q

What are the clinical presentation of adrenal hormone excess?

A
  • Cortisol: weight gain and cushingoid features
  • Mineralocorticoid: high BP and low K
  • Androgen: increased male characteristics in women
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3
Q

What is the clinical presentation of ACTH excess?

A

Skin pigmentation melanocyte stimulation

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4
Q

In what conditions is hyper-pigmentation seen?

A

pigmentation seen in Addison’s and ACTH-driven cushings

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5
Q

What is the clinical presentation of catecholamine excess?

A
  • Acute episodes
  • Sweating
  • Anxiety
  • Palpitations
  • High or low BP
  • Collapse
  • Sudden death
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6
Q

What are the biochemical assessments for suspected adrenal cortex deficiency and what would they show?

A
  • Electrolytes: low Na, high K in aldosterone deficiency*
  • 09:00 basal cortisol: low - when it should be high
  • Stimulation test: inject synthetic ACTH (synacthen)

*in ACTH deficiency only Na is low but K is normal

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7
Q

What is used in a stimulation test for the HPA (adrenal) axis?

A

Synthetic ACTH: synACTHen

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8
Q

What are the biochemical assessments for suspected adrenal cortex excess and what would they show?

A
  • Electrolytes: high BP, low K
  • Midnight cortisol: high - should be low
  • 24h urine cortisol: high
  • Suppression test: failure to suppress
  • Androgens and derivatives: high
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9
Q

What is used in suppression test for HPA adrenal axis?

A

Dexamethasone (steroid which provides negative feedback to reduce ACTH)

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10
Q

Describe the dexmethasone suppression test

A

• Dexamethasone is a potent synthetic steroid that, when given orally would normally suppress (by feedback inhibition) the secretion of ACTH and thus cortisol.
• If Dexamethasone suppresses of plasma cortisol
by >50% , it indicates Cushing’s disease because for the diseased pituitary, even though it is relatively insensitive to cortisol, it does retain some sensitivity to potent synthetic steroids. Thus suggesting that excess cortisol is produced from the pituitary.
• Suppression does not normally occur in adrenal tumours or ectopic ACTH production.

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11
Q

What would the synacthen test tell us?

A

The administration of Synacthen (a synthetic analogue of ACTH) intramuscularly, would normally increase plasma cortisol by >200 nmol/L. A normal response usually excludes Addison’s disease.

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12
Q

Compare high and low dose dexmethasone test

A

Low dose test done to see if the patient has cushing’s syndrome

  • low cortisol –> normal
  • high/normal cortisol –> cushing’s syndrome

high dose test done to see what might be causing cushing’s syndrome

  • low cortisol –> cushing’s disease
  • high/normal cortisol –> if ACTH low then adrenal cushings, if ACTH high then ectopic tumour producing ACTH
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13
Q

What are the biochemical assessments for suspected adrenal medulla excess?

A

24h urine catecholamines: adrenaline, noradrenaline, dopamine, 3-Methoxy-Tyramine

24h urine metanephrines: (metabolites of adrenaline and noradrenaline) metadrenaline, normetadrenaline

Plasma metanephrines: more sensitive than 24h urine

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14
Q

What should be avoided before biochemical assessment of catecholamines?

A

Avoid certain foods before collection
coffee, coke, bananas, chocolate, vanilla

-false positives

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15
Q

What radiological techniques can be used in assessment of adrenal disease?

A

CT, MRI, MIBG, PET,

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16
Q

What is the main cause of Addison’s disease?

A

Auto-immune

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17
Q

What are the symptoms of Addison’s disease?

A
  • Fatigue • Weakness • Anorexia • Weight loss
  • Nausea • Abdominal pain • Dizziness
  • Pigmentation
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18
Q

What are the signs of Addison’s disease?

A
  • Underweight • Signs of weight loss
  • General malaise • Other auto-immune disease
  • Vitiligo • Thyroid • Postural hypotension
  • Pigmentation
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19
Q

What are some causes of primary adrenal failure (addisons)?

A
  • Auto-immune: isolated or polyglandular
  • Infection: TB, fungal, AIDS
  • Infiltration: amyloid, haemochromatosis
  • Malignancy: lung, breast, kidney
  • Genetic: CAH, adreno-leukodystrophy
  • Vascular: haemorrhage or infarction
  • Iatrogenic: adrenalectomy, drugs
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20
Q

What is adrenal crisis?

A

Exaggerated form of adrenal insufficiency. Usually occurs in a patient with chronic adrenal insufficiency who undergoes stress (trauma, ischemia, surgery)

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21
Q

What are the clinicial features of adrenal crisis?

A
  • Collapse • Hypotension • Dehydration

* Pigmentation • Coma

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22
Q

What is the treatment for adrenal crisis?

A
  • Rapid rehydration with fluids
  • Intravenous hydrocortisone
  • Correction of hypoglycaemia
  • Search for precipitating cause
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23
Q

What is the maintenance treatment for addisons disease?

A

Glucocorticoid: hydrocortisone, prednisolone
Mineralocorticoid: fludrocortisone

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24
Q

When should glucocorticoid dose be increased in addisons disease?

A

During illness - needs to be doubled.

25
What can sudden withdrawal of steroid drugs cause?
Hypo-adrenal crisis
26
When does ACTH deficiency occur and how can it present?
* Occurs in any cause of hypopituitarism * Similar symptoms to primary adrenal failure * No pigmentation as ACTH not raised * No hyperkalaemia as no mineralocorticoid deficiency * Hyponatraemia due to effect of cortisol on free water excretion
27
describe Steroid-induced hypoadrenalism
ACTH suppressed with long-term steroids Abrupt withdrawal can cause hypo-adrenal crisis Important to consider in any unwell patient on steroids Hyponatraemia and hypotension are key clues
28
What are the causes of cushings syndrome?
Pituitary tumour Adrenal tumour Ectopic ACTH
29
What are the symptoms of cushing's syndrome?
* Round pink face with round abdomen * Skinny and weak arms and legs * Thin skin and easy bruising * Red stretch marks ('striae') on abdomen * High blood pressure and diabetes * Osteoporosis (thin bones)
30
What androgenic symptoms may be present in adrenal cushing's syndrome?
Hirsutism (male hair pattern in females), acne, greasy skin Virilising features in large tumours: androgenic alopecia, deep voice, clitoromegaly
31
Will the ACTH level be high or low in adrenal cushings syndrome?
ACTH is suppressed ‘ACTH-independent’ cushing’s (due to negative feedback) unlike pituitary and ectopic ACTH ‘ACTH-dependent’
32
What is the treatment for adrenal cushings syndrome?
Adrenalectomy
33
What is Conn's syndrome?
aldosterone-secreting adrenal adenoma
34
what is Primary hyperaldosteronism?
excess production of aldosterone from adrenal gland
35
What are 2 causes of hyeraldosteronism?
aldosterone-secreting adrenal adenoma (Conn's syndrome) | bilateral adrenal hyperplasia (no discrete adenoma)
36
How can we confirm primary hyeraldosteronism?
* clinical suspicion – hypertension and hypokalaemia * confirmation of high aldosterone and suppressed renin * scan shows adrenal adenoma or bilateral hyperplasia
37
What are the 2 major effects of hyperaldosteronism?
Hypertension and hypokalaemia.
38
How are primary aldosteronisms treated?
Conn's: surgery, remove tumour | Hyperplasia: spironolactone
39
What is congenital adrenal hyperplasia?
Rare inherited autosomal recessive disorders characterized by a deficiency of enzymes causing a block in adrenal cortex pathway. - adrenal crisis and ambiguous genitalia
40
Which enzyme is most commonly deficient in CAH and what does this lead to?
21 hydroxylase Lack of enzyme leads to: - Low cortisol and aldosterone - High male hormone (androgens)
41
Describe why congenital adrenal hyperplasia leads to genital ambiguity in females infants
• genetic defect in one or more of the enzymes required for the synthesis of the corticosteroid hormones from cholesterol. • Due to a lack of cortisol the pituitary is not subjected to negative feedback control and therefore secretes large amounts of ACTH which in turn causes enlargement of the adrenal cortex (hyperplasia). • The most common form is deficiency of the enzyme 21-hydroxylase which results in less glucocorticoid and mineralocorticoid production. The precursor of these hormones is therefore diverted to more androgen synthesis (androstenedione & testosterone). • This can result in genital ambiguity in females infants and “Salt-wasting crises” due to a high rate of sodium loss in urine (due to loss of aldosterone).
42
What does CAH present with?
- Hypotension - Hyponatraemia - Hyperkalaemia | - Hypoglycaemia - Virilisation
43
WHat is the treatment for CAH?
Treat adrenal crisis Determine sex of baby Long term GC and MC Corrective surgery
44
What are symptoms of Conn;s syndrome?
High blood pressure, occasional muscular weakness & spasms, tingling sensations, and excessive urination.
45
What is the effect of excess aldosterone on the kidneys in Conn's syndrome?
it increases sodium reabsorption and potassium secretion resulting in an increased blood volume and pressure. Increased blood pressure and renal perfusion cause a decrease in renin release from the kidney. In a normal individual decreased renin would lead to decreased aldosterone. However, in Conn’s syndrome the decreased renin (and angiotensin II) does not lead to a decrease in aldosterone and this can be used as a diagnostic criteria for the disease.
46
What causes unilateral and bilateral forms of Primary hyperaldosteronism?
``` Primary hyperaldosteronism (Conn’s Syndrome) can be caused by hyperactivity of one (unilateral disease) or both (bilateral disease) adrenal glands. The unilateral form of the disease is usually caused by an adenoma whereas rare genetic syndromes like familial hyperaldosteronism type I and II may cause both glands to be hyperactive ```
47
WHat are 2 types of catecholamine secreting tumours?
- phaeochromocytoma | - paraganglioma
48
What is a phaeochromocytoma?
Tumour of the adrenal medulla (90%)
49
What is a paraganglioma?`
It is a Chromaffin cell neoplasm that lies outside the Adrenal Gland. It only secretes Norepinephrine. (10%)
50
What makes a catecholamine secreting tumour more likely to be genetic inheritance?
More likely if its: • Extra-adrenal • Malignant • Bilateral
51
What are the symptoms of hypercatecholamines?
* Acute episodes • Sweating • Panic attacks | * Palpitations • High or low BP • Collapse
52
What are the symptoms of an acute crisis of hypercatecholamines?
* Hypertensive crisis * Encephalopathy * Hyperglycaemia * Cardiac arrhythmias * Sudden Death
53
What are the investigations for increased catecholamines?
24h urine metanephrines 2-3 x collections needed Plasma metanephrines Neuro-endocrine marker: Chromogranin A
54
What is the management for catecholamine excess?
α-blockade phenoxybenzamine β-blockade: bisoprolol surgical excision
55
Why is it important to give α-blockade before β-blockade?
Blocking β first causes unopposed α-stimulation which can cause a hypertensive crisis
56
What are the actions of androgen?
Androgens stimulate the growth and development of male genital tract and male secondary sexual characteristics including height, body shape, facial and body hair, lower voice pitch. They also have anabolic actions especially on muscle protein. Over secretion of adrenal androgens produces effects in the female that include: excessive body hair growth (hirsutism), acne, menstrual problems, virilisation, increased muscle bulk and a deepening voice
57
What are the actions of oestrogen?
Oestrogens stimulate growth and development of female genital tract, breasts and female secondary characteristics including broad hips, accumulation of fat in breasts and buttocks, body hair distribution. They are weakly anabolic and decrease circulating cholesterol levels.
58
How can you distinguish between the different possibilities causing cushing's syndrome?
1. check ACTH rhythm 2. If elevated ACTH, suggests an ACTH dependant cause so check if Cortisol supressed in high dose Dexamethasone suppression test. Yes --> Benign pituitary adenoma secreting ACTH (Cushing’s disease) no --> Ectopic tumors producing ACTH (&/or CRH) e.g. small cell lung cancer 3. If normal or low levels of ACTH, suggests an ACTH independent cause so check if Prescribed glucocorticoids taken. Yes --> Exogenous Cushing’s No --> Excess cortisol produced by adrenal tumor (Adrenal Cushing’s)

Semester 2 - MEH (23 decks)

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