Adrenal Gland Clinical Flashcards
The adrenal, simply, controls what?
Salt
Sugar
Sex
Stress
What are the layers of the adrenal gland?
Zona Glomerulosa
Zona Fasciculata
Zona Reticularis
Medulla
When you have raised suspicion of adrenal dysfunction, how do you approach it?
Is it functioning high or low? Is it primary, secondary or tertiary? What could be the cause? If tumour: removable? Deficiency: can it be fixed?
How is cortisol secretion stimulated?
CRH from hypothalamus
ACTH from anterior pituitary
Elevated cortisol inhibits what?
Secretion of CRH and ACTH
Hypofunction of the adrenal gland is usually due to what?
Adrenal dysgenesis
Adrenal dysfunction
Impaired steroidogenesis
What is the precursor to catecholamines?
Dopamine
What are the causes of Adrenal Hyposecretion?
Primary Adrenal Insufficiency
Adrenal Enzyme defects
What are the causes of primary adrenal insufficiency?
Addison’s Disease
What are the different causes of Addison’s disease?
AUTOIMMUNE Invasion Infiltration Infection Infarction Iatrogenic
Addison’s disease causes what?
Adrenal insufficiency
Which adrenal enzyme deficiency typically leads to hyposecretion?
21-hydroxylase
What is the role of 21-hydroxylase?
Formation of aldosterone and cortisol from progesterones
Autoimmune dysfunction usually attacks what in autoimmune addison’s?
Adrenal autoantibodies to 21-hydroxylase (70%)
Lymphocytic infiltrate of adrenal cortex
Which conditions are typically associated with Autoimmune Addison’s disease?
Thyroid disease (20%) T1DM (15%) Premature ovarian failure (15%)
What are the common symptoms of primary adrenal failure?
Fatigue, weakness, anorexia, weightloss (100%)
Skin pigmentation/vitiligo
Hypotension
Unexplained Vom/diarrhoea
What are the rare symptoms of primary adrenal failure?
Salt craving
Postural symptoms
How does Primary Adrenal Failure cause skin pigmentation?
Excess ACTH co-stimulates melanocyte sytimulating hormone
Which other factors can give clues to adrenal failure?
Disproportionate illness severity and dehydration/hypotension
Unexplained hypoglycaemia
Other endocrine features
Previous depression
How is a diagnosis of adrenal insufficiency made?
Symptoms
Bloods
Cortisol (low)
Synacthen test
How do you treat a very unwell patient with high suspicion of Adrenal insufficiency?
Treat with steroids and do Synacthen test later
How do you treat a very unwell patient with high suspicion of Adrenal insufficiency?
Treat with steroids and do Synacthen test later
What is the short synacthen test?
Give 250ug Tetracosactrin
Push adrenal glands
Look at response
(Test for adrenal insufficiency)
How do you interpret cortisol levels in the short synacthen test?
Over 2hrs
>500nmol/l normal
<150nmol/l 2ndary adrenal insufficiency
<50nmol/l primary adrenal insufficiency
How do short synacthen test results give a diagnosis of primary adrenal failure?
Impaired cortisol response with an elevated ACTH
How do short synacthen test results give a diagnosis of secondary adrenal failure?
Lesser cortisol response
ACTH stays low
How is congenital adrenal hyperplasia diagnosis?
Samples of cortisol taken and tested for 17-OH progesterone to exclude 21-hydroxylase deficiency
What does a normal response to rapid ACTH stimulation test tell you?
Excludes primary adrenocortical insufficiency
What should you test after an abnormal ACTH stimulation test?
Test Plasma ACTH
What does suppressed ACTH tell us?
Secondary Adrenocortical insufficiency
What does elevated ACTH tell us?
Primary adrenocortical insufficiency
You diagnose a patient with Addison’s disease, what do you do next?
Check adrenal autoantibodies
What do you do with a patient with Addison’s disease and positive for adrenal autoantibodies?
Screen for other features of APS (autoimmune polyendocrine syndromes)
What do you do with a patient with Addison’s disease and negative for adrenal autoantibodies?
Men: Check VLCFA (FIRST)
- If -ve, adrenal imaging
Women: Adrenal imaging
A patient with Addison’s disease, negative for adrenal autoantibodies and VLCFA positive has what?
Adrenoleucodystophy
What factors are looked for in adrenal imaging?
Infiltation
Infarction
Haemorrhage
Infection
What therapies are given for adrenal hyposecretion?
Glucocorticoid treatment
Mineralocorticoid replacement
What is the typical glucocorticoid replacement therapy?
HYDROCORTISONE 20-30mg
Prednisolone 7.5mg
Dexamethasone 0.75mg
Divided doses to mimic diurnal variation
What is the typical mineralocorticoid replacement therapy?
Synthetic steroid
Fludrocortisone 50-300ug
Which patients are likely to need steroid therapy?
Hypoadrenal
Patients on steroids who suppress the pituitary adrenal axis
18/12 recent treatment
How should steroid therapy be changed for patients with short-lived illness?
Double glucocorticoid dose
How should steroid therapy be changed for patients with major illness/surgery?
100mg hydrocortisone IV
Reduce as stress abates
What are the endocrine causes of hypertension?
Primary Hyperaldosteronism Pheochromocytoma Cushing's disease Acromegaly Hyperparathyroidism Hypothyroidism Congenital Adrenal Hyperplasia
What conditions of the adrenal cortex cause hypersecretion?
Cushing’s syndrome
Conn’s syndrome
What conditions of the adrenal medulla cause hypersecretion?
Phaeochromocytoma
Phaeochromocytoma causes secretion of what?
Catecholamines
Cushing’s syndrome causes secretion of what?
Cortisol
Androgens
Conn’s syndrome causes the secretion of what?
Aldosterone
What is Cushing’s syndrome?
Excess corticosteroids
What is the role of cortisol?
Tissue breakdown
Sodium retention
Insulin antagonism
What are the symptoms of Cushing’s syndrome?
Central obesity Hypertension Glucose intolerance Moon face Striae Mood changes Amenorrhoea
Cushing’s syndrome not caused by corticosteroid therapy is divided into which classes?
ACTH-dependent
ACTH-independent
What are the causes of ACTH-dependent Cushing’s?
Pituitary tumour (Cushing's disease) Ectopic ACTH secretion
What type of tumour causes Cushing’s disease?
Basophil adenoma
What are the causes of ACTH-independent Cushing’s?
Adrenal tumour (adenoma, carcinoma) Primary nodular hyperplasia
What is the initial screen for hypercortisolism?
Overnight Dexamethasone suppression test
24hr urine free cortisol
How is Hypercortisolism confirmed?
24hr urine free cortisol
Low dose dexamethasone test
How is ACTH dependent/independent hypercortisolism differentiated?
Paired morning-midnight ACTH cortisol
If hypercortisolism is confirmed to be ACTH dependent, what is the next step?
Determination whether or not in the pituitary
High dose dexamethasone test
How is an ACTH secreting tumour located?
MRI Sella
CT adrenals/chest
BIPSS
What sources produce the most abnormal ACTH?
Ectopic sources
What is the test for lateralising pituitary lesion?
Simultaneous bilateral inferior petrosal sinus and peripheral vein sampling
What is the typical cause of Conn’s Syndrome?
Adenoma
Bilateral hyperplasia
Elevated aldosterone causes what?
Elevated blood volume
Elevated blood pressure
Elevated urine K+
↓ Renin
How is suspected hyperaldosteronism screened?
Plasma PA/PRA ratio
What does a PA/PRA ratio > 20 tell us?
Primary hyperaldosteronism
What does PA/PRA ratio < 20 tell us?
(Less reliable)
Secondary hyperaldosteronism
Essential Hypertension
What do you test for in a patient with hypertension and hypokalemia?
Plasma renin activity (PRA)
Plasma aldosterone concentration (PAC)
↑Renin ↑Aldosterone in a patient with hypertension and hypokalemia tells us what?
Investigate for Secondary hyperaldosteronism
What are the causes of secondary hyperaldosteronism?
Renovascular hypertension Diuretic use Renin-secreting tumour Malignant hypertension Coarctation of the aorta
↑Aldosterone (PAC) ↓Renin (PRA) in a patient with hypertension and hypokalemia tells us what?
Investigate for primary hyperaldosteronism
↓Renin ↓Aldosterone in a patient with hypertension and hypokalemia tells us what?
Congenital adrenal hyperplasia
Exogenous mineralocorticoid
Cushings/Liddle’s
11 beta HSD deficiency
How is hyperaldosteroneism confirmed?
Urinary Sodium
24hr urine aldosterone
4 days of salt loading
How is the source of aldosterone found?
CT adrenals
Upright posture test
Plasma 18-hydroxycorticosterone
What are the symptoms of phaeochromocytoma?
Hypertension
Paroxysmal attacks
How do paroxysmal attacks present?
Headache Sweating Palpitations Tremor Pallor Anxiety
What makes Phaeochromocytoma the 10% tumour?
10% extra adrenal
10% malignant
10% multiple
10% hyperglycaemic
How do you test for phaeochromocytoma?
24hr urine:
Total metanephrines (solo in low suspicion)
Catecholamines
Plasma metanephrines
What should be done next ina
patient with Increased metanephrines or catecholamines?
Localisation
Adrenal/abdominal MRI/CT
What other tests should be performed in patients with phoechromocytoma?
Genetic testing
Tumour phenotype
What must never be performed on a pheochromocytoma?
Biopsy
What is the most common cause of congenital adrenal hyperplasia?
90% due to 21-hydroxylase deficiency
How does Congenital adrenal hyperplasia present?
Neonatal salt-losing crisis
Ambiguous genitalia (girls)
Pseudo-precocious puberty (boys)
Hirsutism
What hormone changes are seen in 21-hydroxylase deficiency?
Decreased aldosterone, cortisol
Increased sex hormones
