Adrenal Flashcards
Adrenal
What are the 4 regions of the adrenal glands?
IN –> OUT:
1 -Adrenal medulla
Adrenal cortex:
2 -zona reticularis
3 -zona fasciculata
4 -zona glomerulosa
1) stress (adrenaline/noradrenaline)
2) sex (androgens)
3) sugar (glucocorticoids)
4) salt (mineralocorticoids- aldosterone)
What is produced by the adrenal medulla?
Catecholamines (adrenaline, noradrenaline)
What is produced by the zona reticularis?
Androgens (DHEA, androstenedione)
What is produced by the zona fasciculata?
Glucocorticoids (cortisol, corticosterone, cortisone)
What is produced by the zona glomerulosa?
Mineralocorticoids (aldosterone)
What effect do catecholamines have on the body?
Increased cardiac activity, blood pressure, glycogen breakdown, blood glucose levels
What effect do glucocorticoids have on the body?
Release AA from skeletal tissue, lipids from adipocytes, promote liver gluconeogenesis
What effect do mineralocorticoids have on the body?
Increased renal reabsorption of Na+ and H2O, renal K+ excretion
What is the adrenal medulla stimulated by?
Sympathetic preganglionic fibres
What is the zona reticularis stimulated by?
ACTH
What is the zona fasciculata stimulated by?
ACTH
What is the zona glomerulosa stimulated by?
Angiotensin II
high K+
low Na+
inhibited by ANP/BNP
What is the hypothalamic-pituitary-adrenal axis?
Hypothalamus –> CRH
Anterior pituitary –>ACTH
Adrenal cortex–> cortisol (supplies -ve feedback to the hypothalamus and anterior pituitary)
What is adrenal insufficiency?
an adrenal cortex disorder where there is a decreased production of adrenocortical hormones (cortisol, aldosterone, DHEA)
What are the causes of primary adrenal insufficiency?
TB – most common worldwide
Autoimmune – most common in UK
What are the causes of secondary adrenal insufficiency?
HYPOPITUITARISM
- Pituitary adenoma
- Sheehan’s syndrome
- Surgery/radiotherapy
- Pituitary apoplexy
What are the causes of tertiary adrenal insufficiency?
- Brain tumour
- Sudden withdrawal of long term corticosteroids
What is the main thing you would be looking for in a Pt with glucocorticoid deficiency?
Hypoglycaemia
What is the main thing you would be looking for in a Pt with mineralocorticoid deficiency?
Hyponatraemia
Hyperkalaemia
What are the symptoms of adrenal insufficiency?
Fatigue, weakness Anorexia Weight loss Nausea and vomiting Arthralgia and myalgia Abdominal pain Depression Salt cravings
What are the signs of adrenal insufficiency?
- Mucocutaneous hyperpigmentation in buccal mucosa and sun exposed areas (due to raised ACTH stimulating melanocytes)
- Postural hypotension
- Loss of body hair (in females)
What is the investigations you should do in a Pt with adrenal insufficiency? What would you see?
1) Bloods – U+Es, FBC
- ↓Na+
- ↑K+
Due to ↓ aldosterone production
2) 9am cortisol = ↓
3) Short SynACTHen test (diagnostic)
4) Adrenal antibodies
5) Adrenal CT/MRI
What is the diagnostic investigation you should do in a Pt with adrenal insufficiency?
synACTHen test
250mcg tetracosactide
At what synACTHen test cortisol levels can you rule out primary adrenal insufficiency?
Baseline cortisol >170nmol/L
30 min cortiosl >600nmol/L
What is the management for adrenal insufficiency?
Lifelong glucocorticoids and mineralocorticoids
eg. hydrocortisone + fludrocortisone
Raise dosage if stressed eg. trauma, surgery, infection
What are the complications of adrenal insufficiency?
- Addisonian crisis
- Secondary Cushing’s syndrome
- Osteoporosis (long term XS glucocorticoids)
- Hypertension (long term XS glucocorticoids)
What is an Addisonian crisis?
Acute adrenal insufficiency with major haemodynamic collapse
What are the causes of an Addisonian crisis?
- Sepsis/surgery with a background of chronic insufficiency
- Steroid withdrawal
- Adrenal haemorrhage (Waterhouse-Friderichsen syndrome)
What is the presentation of an Addisonian crisis?
Hypotensive shock Tachycardia Abdo pain Confusion Lethargy Coma
ELECTROLYTE ABNORMALITIES
- Hyperkalaemia
- Hypercalcaemia
- Hypoglycaemia
- Hyponatraemia
What is the management of a Pt with an Addisonian crisis?
- Hydrocortisone sodium succinate 50-100mg IV every 6-8 hrs
- 1L bolus IV saline followed by 2-4L over 24 hrs
- Glucose to correct hypoglycaemia, risk of worsening hyponatraemia
What is Cushing’s syndrome?
Chronic inappropriate elevation of free circulating cortisol
What are the causes of Cushing’s syndrome?
EXOGENOUS CUSHING’S SYNDROME
- chronic excess steroid use
ACTH-DEPENDANT
- excess ATCH from pituitary adenoma (Cushing’s disease)- 85%
- excess ATCH from ectopic tumour (small cell lung cancer)- 5%
ACTH-INDEPENDANT
- excess cortisol from adrenal adenoma 10%
What are the symptoms of Cushing’s syndrome?
Weight gain Fatigue Depression/psychosis Insomnia Amenorrhoea/oligomenorrhoea Poor libido Hirsutism/acne/balding Thin skin Easy bruising Back pain Muscle weakness Polyuria/polydipsia
What are the signs of Cushing’s syndrome?
Moon face Facial plethora Interscapular fat pad Hirsutism/acne/balding Thin skin Bruising Hypertension Ankle oedema Pigmentation Proximal myopathy Osteoporosis Pathological fractures Skin infections