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endocrine pathology + medicine > endocrine- adrenal > Flashcards

endocrine- adrenal Flashcards

1
Q

Location of adrenal glands?

A

Superior poles of kidney

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2
Q

Weight of adrenal glands

A

4 gram each

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3
Q

What are the layers of the adrenal gland?

A

capsule, medulla, cortex

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4
Q

What are the areas of the cortex and their secretions

A

zona fasiculata (and glomerulosa)- glucocorticoids
zona glomerulosa- mineralocorticoids
zona reticularis-sex steroids

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5
Q

Where do you source cholesterol to make these secretions from the cortex?

A

diet

acetate is converted to cholesterol by CoA reductase enzyme

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6
Q

What are the 3 conditions a/w adrenocortical hyperfunction

A 
•Hypercortisolism (Cushing syndrome)
•Hyperaldosteronism
Primary
Secondary
•Adrenogenital syndromes
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7
Q

Causes of hypercotisolism?

A

Excess secretion of glucocorticoids

Exogenous(most common) and endogenous

Endogenous causes –1° hypothalamic-pituitary diseases
•Pituitary disease (70-80% of cases)
•Pituitary adenoma [Cushing disease]
–Adrenal causes
•Adenoma, carcinoma, nodular hyperplasia (10-20% of cases)
–Paraneoplastic cause
•Secretion of ectopic ACTH by a neoplasm (small cell carcinoma, carcinoid tumours, medullary

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8
Q

Differentiate pituitary Cushing syndrome and Cushing disease

A

Cushing syndrome is hypercortisolism due to any cause
Cushing disease involves a pituitary adenoma secreting ACTH (adenocorticotropin adenoma) which acts on the adrenal cortex causing bilateral hyperplasia which causes an increase in cortisol AND androgens (-ve feedback still occurs for remaining of hypothalamus and intact pituitary ; i.e decreased ACTH production and )

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9
Q

What are the early manifestations of Cushing syndrome?

A

Weight gain and hypertension

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10
Q

What are the other symptoms of cushing’s syndrome?

A

moon face
buffalo hump
decreased muscle mass- due to atrophy of fast twitch myofibres
hyperglycaemia- glucocorticoids activate hepatic gluconeogensis and inhibit glucose uptake by cells
fragile thin skin, cutaeneous striae, easily bruised - catabolic effect on protein which includes loss of collagen
infection- supression of immune system by glucocorticoids
mental distubances(psychosis, depression, mood swings)
hirsuitism and menstrual abnormalities
osteoporosis- induce bone resorption

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11
Q

Diagnosis of Cushing

A

Overall cortisol secretion: 24hr cortisol urine collection

Cortisol rhythm and dynamics: dexamethasone suppression test

  • 1mg overnight
  • low dose 48hr

also late night salivary cortisol can be assessed for rhythm and dynamics of cortisol

Dexamethasone is a potent synthetic glucocorticoid; its aim is to suppress endogenous ACTH (and cortisol).
Thus dexamethasone does not affect adrenal Cushing syndrome (increase in cortisol and decrease in ACTH due to -ve feedback)
and ectopic ACTH (increase in ACTH and cortisol)

Assess if ACTH dependent vs independent
measure ACTH and if depressed- due to adrenal cause of Cushing
if normal/increased: ectopic / pituitary Cushing

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12
Q

Explain the pathogenesis of pituitary cushings, adrenal cushings and ectopic cushings

A

Pituitary Cushings
secretion of ACTH from pit adenoma - hyperplasia of adrenal cortex causing release of cortisol and androgens which have a -ve feedback on hypothalamus and intact pituitary. So thus only source of ACTH is from pit adenoma

Adrenal Cushings
cortisol producing tumor in adrenal cortex (no androgens) causes -ve feedback on hypo and pit causing decreased ACTH

Ectopic Cushings
small cell carcinoma of lung secreting excessive ACTH stimulating cortex-> hyperplasia -> excessive secretion of cortisol and androgens -> -ve feedback on pit and hypothalamus where NO ACTH is produced

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13
Q

List some other multisystem complications of Cushing’s syndrome

A

Cardiovascular: hypertension, vasculitis, dyslipidemia

CNS: mood swings, psychosis

GI tract: peptic ulcers, GI bleeding, pancreatitis

Immune system : Broad immunosuppression

Integument: poor wound healing, striae, petechia, erythema

Musculoskeletal system: muscle atrophy, osteoporosis, bone necrosis

Eyes: cataracts, glaucoma

Kidney: increased sodium and potassium retention

Reproductive system: delayed puberty, fetal growth and hypogonadism

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14
Q

How can you sample for ACTH

A

simultaneous bilateral petrosal sinus and peripheral vein sampling of ACTH

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15
Q

Management of Cushing

A

Surgical
Transsphenoidal surgery for pituitary adenoma

Adrenalectomy (adrenal Cushing’s or failed pituitary surgery)

Pituitary radiotherapy

Medical treatment: metyrapone, ketoconazole, aminoglutethimide, RU 486

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16
Q

What is the function of aldosterone?

A

Retention of water and sodium, excretion of potassium and causing hypertension by acting on renal distal tubules and collecting ducts

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17
Q

Describe general idea of primary causes of Hyperaldosteronism and outcome

A

increase in endogenous production of aldosterone. Supresses RAS system
marked by increase in aldosterone and decrease in renin
however it clinically presents as hypertension and hypokalemia

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18
Q

What causes excess primary aldosterone secretion?

A

Aldosterone producing adenoma of the adrenal cortex.
This is seen in Conn’s syndrome where adenoma is bright yellow, <2cm occurs L>R, occurs more in females in midlife.

Adrenocortical hyperplasia by excess of pituitary factor that results in cortical hyperplasia

Glucocorticoid suppressible hyperaldosteronism
this is where a mutation in glomerulosa cells that causes them to be responsive to ACTH , so thus secretion of ACTH from pituitary causes aldosterone release

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19
Q

Treatment of primary hyperaldosteronism

A

Adenoma- surgical removal

hyperplasia-aldosterone antagonist- spironolactone

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20
Q

What are the causes of sec hyperaldosteronism and outcome?

A

Production of aldosterone secondary to activation of RAS system marked by increased aldosterone and increase in renin

This occurs in pregnancy, hypovolaemia and oedema(i.e congestive heart failure and cirrhosis) and renal artery stenosis.

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21
Q

Treatment for sec hyperaldosteronism

A

Treat underlying cause

22
Q

Describe the RAS system

A

Renin Angiotensin and aldosterone system aims to increase water and salt retention to increase blood volume and increase perfusion of juxtaglomerular apparatus

This is done by angiotensinogen produced by the liver being converted to angiotensin I by renin. This is then converted to angiotensin II by angiotensin converting enzyme (Derived from lungs and kidney epithelium) . Angiotensin II causes aldosterone release from adrenal cortex

As well as other important outcomes:

  • increase in sympathetic activity
  • acts on renal distal tubules and collecting ducts causing retention of NACL and water and excretion of K+
  • acts on hypothalamus to cause ADH secretion which acts on collecting duct to cause H20 retention
  • causes arteriolar vasoconstriction to cause an increase in bp
23
Q

Outline adrenogenital syndromes

A

Disorders of sexual differentiation
Primary gonadal disorders
Primary adrenal disorders

24
Q

What are the compounds secreted from zona reticularis?

A

dehydroepiandrosterone, androstenedione.

These are converted to testosterone in peripheral tissues

25
Q

Describe the adrenogenital syndromes

A

•Androgen adrenocortical neoplasm:
–Carcinoma>adenoma
•Congenital adrenal hyperplasia:
–Group of autosomal recessive disorders
–Deficiency/lack of a particular enzyme involved in synthesis of cortical steroids (mostly cortisol)
–Steroidogenesis channeled into increased production of androgens -> virilisation
–Deficiency in cortisol results in ACTH increased -> adrenal hyperplasia
–May impair aldosterone secretion

21-Hydroxylase deficiency (90% of these cases)
Converts progesterone to 11-deoxycorticosterone
No mineralocorticoid and deficient cortisol synthesis
Excess production of androgens
Hyponatremia, hyperkalaemia inducing acidosis, hypotension , cardiovascular collapse and death

26
Q

Classify adrenal hypofunction

A

Primary ACUTE and CHRONIC adrenocortical insuffiency

secondary adrenocortical insufficiency

27
Q

Describe primary Acute adrenocortical insuffiency

A

a/w acute adrenal crisis which occurs in
pts who take exogenous corticosteroids-> rapid withdrawal and failure to produce corticosteroids due to atrophy of gland
pts undergoing stress (surgery, trauma, infection) that required increased steroid output by glands
bilateral adrenal haemorrage ( bacteremic infections particularly, DIC, anticoagulant therapy)

28
Q

How does acute adrenal crisis present?

A

abdominal pain, hypotension, intractable vomiting, vascular collapse, coma

29
Q

What typically causes bilateral adrenal haemorrhage? Outcomes?

A

WATERHOUSE-FRIDERICHSEN SYNDROME
Neisseria meningitidis septicaemia ( as well as pseudomonas, haemophilus, staph)
DIC- purpura
rapidly progressive hypotension-shock

Course is abrupt and devastating

30
Q

What age group waterhouse occur in typically

A

children

31
Q

Describe primary chronic Adrenocortical insuffiency

A

•Addison disease
•Progressive destruction of adrenal cortex
•90% cortex destroyed clinical manifestations
•Pathogenesis
–90% cases due to
1.Autoimmune adrenalitis (60-70% of cases)
2.TB
3.Metastatic carcinoma (lung + breast majority)

32
Q

What genotype of adrenalitis a/w?

A

HLA B8 and DR3

33
Q

features of addisons

A

Early manifestations:
Weight loss, hyperpigmentation.

•Progressive weakness
•Fatigability
•GI symptoms (Anorexia, N&V, weight loss)
•Hyperpigmentation of skin  ↑ACTH  stimulate melanocytes (not seen in adrenocortical insufficiency due to 1° pituitary or hypothalamic disease)
•Hyperkalaemia, hyponatraemia, hypotension (aldosterone deficiency)
•Hypoglycaemia (glucocorticoid deficiency)
Loss of libido (women) , low QoL (androgen deficiency)
•Stresses -> acute adrenal crisis

34
Q

Causes of secondary adrenocortical insufficiency

A

This occurs secondary to mets carcinoma, irradiation, infarction and infection of the pituitary gland; thus no ACTH production. This causes no cortisol and sex steroid produced , however aldosterone normal.

35
Q

How do you differentiate if primary vs sec causes of adrenal insufficiency?

A

administration of exogenous ACTH
secondary- rise in cortisol
primary- no rise in cortisol (esp in Addison’s where theres progressive destruction of cortex- no gland to make cortisol)

36
Q

Describe adrenocortical neoplasms

A

carcinoma /adenoma that occurs in females 30-50
responsible for any form of hyperadrenalism

functioning: high cortisol -> suppression of endogenous ACTH -> atrophic adjacent cortex and contralateral gland

37
Q

Describe features of adenomas of adrenal cortex

A

clinically silent
Micro: cells similar to cortex w mild pleomorphism

Macro:
well circumscribed , small <5 cm, <30g
yellow coloration due to lipid content in cells
cystic degeneration, haemorrhage or calcification occurs

Tx:surgical excision

38
Q

Describe carcinoma of adrenal cortex

A

rare, functional>non functional -> virulism and hyperadrenalism

Macro: 20cm, haemorrhage, necrosis, cystic change

Micro: well differentiated cells to undifferentiated cells

Invasion to ADRENAL VEIN, vena cava and lymphatics

39
Q

Where does mets typically happen w adrenocortical carcinoma

A

lung, regional lymph node and other viscera

40
Q

Describe adrenal myelolipoma

A

benign entity
fat and haematopoetic cells
incidental findings

41
Q

What is the adrenal medulla composed of?

A

–Neuroendocrine cells (chromaffin cells) -> catecholamines

–Sustentacular cells (supporting cells)

42
Q

What are the diseases of adrenal medulla?

A

–Neoplasms of chromaffin cells (phaeochromocytoma)
–Neuronal neoplasms (neuroblastomas, ganglion cell tumours)
•Neuroblastoma - sporadic but familial cases do occur; most common extracranial tumour of childhood

43
Q

How does phaechromocytoma present histologically?

A

polygonal/spindle cells- Zellballen

44
Q

Features of phaechromocytoma

A

•Uncommon neoplasms
•Surgically correctable form of hypertension
–0.1%-0.3% of hypertensive patients
•May be associated with other endocrinopathies (may secrete ACTH or somatostatin)
•10% extra-adrenal paraganglia (referred to as paragangliomas)
•90% sporadic; 10% occur with familial syndromes (MEN syndromes, type I neurofibromatosis, von Hippel Lindau disease, Sturge Weber syndrome)
•Bilaterality; 70% familial vs. 10% non-familial
•10% are malignant (adrenal) vs. 20-40% extra-adrenal

45
Q

What is the rule a/w phaeochromocytoma?

A 
‘Rule of 10s’
•10% are extra-adrenal (paragangliomas).
•10% (of non-familial) are bilateral.
–50% in cases associated with familial syndromes.
•10% are malignant.
46
Q

How many pts w phaeochromocytoma/paragangliomas have germ line mutation?

A

25-30%

47
Q

What are the clinical features of phaeochromocytoma?

A

–Hypertension, tachycardia, palpitations, headaches, sweating, tremor
–Abdominal/chest pain
–Sustained hypertension (two thirds cases)
–Paroxysmal episodes of hypertension – exercise, stress, change in posture, palpation in region of tumour cause release of catecholamines
–“Catecholamine cardiomyopathy” (myocardial instability and ventricular arrhythmias -> due to vasomotor constriction of myocardial circulation)

48
Q

How do you diagnose and treat phaeochromocytoma?

A

24 hr urine collection of catecholamines and metabolites

Tx: surgical excision after pre operative and intra operative meds to prevent adrenal crisis

49
Q

What are the metabolites collected in the urine sample?

A

VMA, metanephrines

50
Q

What are the extraadrenal tumors?

A 
•Paragangliomas
–Carotid body tumours (carotid body)
–Chemodectomas (jugulotympanic body)
•10-40% malignant (recurring after resection)
•10% metastasize widely
•15-25% multicentric

endocrine pathology + medicine (4 decks)

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