Adrenal disease Flashcards
Function of adrenal cortex
Glomerulosa-
Mineralocorticoid production: aldosterone.
- Increases fluid abnormal, controls Na and K balance.
Fasciculata-
Glucocorticoid production: cortisol
- Increases fat, carb and protein metabolism.
Reticularis-
Androgen production: DHEA, DHEA-S, androstenedione
- Development of secondary sex organs.
Adrenal cortex control
Hypothalamus releases CRH to anterior pituitary.
Anterior pituitary releases ACTH to adrenal cortex
- Stimulates release of cortisol, aldosterone and androgens.
Increase in corticosteroids suppresses release of ACTH and CRH.
Primary adrenal insufficiency
- Definition
Addison’s disease
- Low cortisol and mineralocorticoid release due to destruction of adrenal cortex.
Causes
- Autoimmune destruction (most common)
- TB
- Adrenal metastasis
- Adrenal haemorrhage
Investigations for adrenal insufficiency
FBC
- Anaemia
- Eosinophilia
U+E
- Hyponatraemia
- Hyperkalaemia
- Uraemia
Calcium
- Hypercalcaemia
Glucose
- Hypoglycaemia
SynACTHen test
- Measure cortisol before and 0.5 hours after synACTH.
- Exclude Addison’s if cortisol >550nmol/L
9am ACTH
- Will be high (>300ng/L) due to no negative feedback
21-hydroxylase adrenal autoantibodies
- Positive in autoimmune
Addison’s treatment
- Replacement
- Hydrocortisone (15-25mg in 2-3 doses)
- Fludrocortisone PO (50-200 micrograms)
Do not stop steroids abruptly due to addisonian crisis risk. Must be weened off
Secondary adrenal insufficiency
- Definition
- Causes
Suppression of adrenal corticosteroid release arising from a non-adrenal cause.
Excess stimulation of pituitary/ hypothalamus can inhibit CRH/ ACTH release.
Causes
- Long term steroid use.
- Hypothalamus/ pituitary tumour.
Addisonian crisis
- Signs and symptoms
- Causes
Signs and symptoms that arise from lack of corticosteroid production (aldosterone and cortisol)
Signs and symptoms
- Abdominal pain
- Vomiting and nausea
- Dizziness and fatigue
Causes
- Untreated addison’s
- Abrupt cessation of long term steroids.
Cushing’s syndrome
- Definition
- Features
Excess of cortisol, leading to the loss of negative feedback control.
- Produces syndrome of signs and symptoms
Features
- Weight gain, central obesity, moon face, buffalo neck lump
- Supraclavicular fat
- Mood changes
- Proximal weakness
- Increased risk of infectiion
- Poor healing
- Gonadal dysfunction
Cushing’s syndrome
- Causes
Prolonged oral corticosteroid use
Cushing’s disease
- Pituitary adenoma
Ectopic ACTH production
Adrenal dysfunction
- Adenoma/ carcinoma
Investigations into Cushings
Overnight Dexamethasone suppression test
- Serum cortisol elevated
- High dose dexamethsone identifies if cortisol stimulation is external of pituitary (ectopic ACTH)
24 urinary free cortisol
Pituitary MRI
Adrenal insufficiency
- Presentation
Symptoms
- Fatigue, weakness, malaise
- Weight loss/ anorexia
- Dizziness/ faint
- Tanned skin
- Abdominal pain, vomitting, nausea
Signs
- Dehydration
- Hyperkalemia, hyponatraemia
- Hypoglycaemia
- Postural hypotension
- Pigmented palmar creases (due to ACTH increase)
Adrenal insufficiency
- Investigations
SynACTHen test
- Cortisol levels will not raise signficantly
9am ACTH
- Elevated
Bloods U+Es - Hyperkalaemia - HypoNa+ - Glucose= low - HyperCa2+ - FC: anaemia, eosinohilia
Addison’s management
Replacement therapy
- Hydrocortisone (cortisol)
- Fludrocortisone (mineralocorticol)
Do not stop steroid abruptly
- Wean off due to risk of crisis
For injury, illness/ stress
- Double steroid doses
Primary aldosteronism
- Definition
- Causes
- Presentation
Excess aldosterone production independent of RAAS
- Causes Na+ and water retention
Causes
- Conn’s syndrome= adrenal, aldosterone producin adenoma
- Adrenal carcinoma
Presentation
- Hypertension
- Hypokalaemia: weakness, cramps, paraesthesiae
- Alkalosis
- Polydipsia/ polyuria
Primary hyperaldosteronism
- Investigations
Bloods
- U+Es: hypokalaemia
- Renin= depressed (affected by diuretics, hypotensivves, steroids)
Genetic testing
