Flashcards in Adrenal Glands and Disorders Deck (69):
____ is formed in the adrenal glomerulosa
____ is formed in the adrenal fasiculata
____ is formed in the adrenal reticularis
Aldosterone promotes __ reabsoprtion and __ excretion
Na reabsorption and K excretion
aldosterone production is stimulated by the ________ apparatus in the kidney
The production of cortisol is controlled by____
When is cortisol highest and lowest?
highest first thing, lowest late at night
where is Na reabsorption promoted by aldosterone?
DCT and collecting duct
Main effects of cortisol on the body?
increased BG, anti-inflammatory effects, increased CO, BP and renal blood flow, osteoporosis, decreased wound healing
androgens produced by the adrenal glands
Produced in the adrenal medulla?
epinephrine (80%), norepinephrin (20%)
Congenital adrenal hyperplasias are inherited in a ____ manner
Pathophysiology in congenital adrenal hyperplasia
deficiency of an enzyme for steroid biosynthesis usually leading to decreased cortisol, increased ACTH and increased androgens
most common enzyme deficiency in congenital adrenal hyperplasia
presentation of congenital adrenal hyperplasia
salt wasting, simple virilising, hyperandrogenism, ambiguous genitalia (girls), poor feeding, poor weight gain, similar presentation to addisons
treatment for congenital adrenal hyperplasa
glucocorticoid replacement, possible mineralocorticoid replacement, restore fertility and achieve maximal growth
Conn's syndrome is...
usually associated with diffuse or nodular hyperplasia of both adrenal glands causing hyperaldosteronism
Common cause of Conn's syndrome
35% are due to benign adenomas
What does a Conn's adenoma look like?
small bright yellow tumour of spironolactone bodies
common symptoms of conn's syndrome?
weakness, cramps, paraesthesia, polyuria, polydipsia and sometimes increased BP; may be asymptomatic
What is the effect of hyperaldosteronism on electrolytes?
increased Na, decreased K
Primary investigation for conn's syndrome?
plasma renin:aldosterone ratio - if raised then investigate with suppression test
Suppression test for conn's syndrome?
failure of plasma aldosterone to suppress by 50% following 2L of saline
How is Conn's syndrome managed surgically?
unilateral laproscopic adrenalectomy - cure of hypokalaemia; cure of hypertension if adrenal adenoma
How is Conn's syndrome managed medically?
use of MR antagonists when bilateral adrenal hyperplasia --> spironolactone, eplerenone
Examples of MR antagonists (K+ sparing diuretics)
What is the most common cause of Cushing's syndrome?
exogenous steroid use
Endogenous cushing's can be ACTH dependent or ACTH independent. What is meant by ACTH dependent Cushings?
ACTH is secreted from a pituitary adenoma causing Cushing's DISEASE (70%) or from an ectopic source such as SCLC or carcinoid tumours (cause adrenal hyperplasia)
Which form of lung cancer may cause Cushing's syndrome?
Small Cell Lung Cancer
Endogenous cushing's can be ACTH dependent or ACTH independent. What is meant by ACTH independent Cushings?
An adrenal adenoma or carcinoma
What group is Cushings most common?
women; 20-40 years
What are some symptoms of Cushing's? (5)
increased weight, mood changes, proximal weakness, gonadal dysfunction (irregular menses, hirsutism, erectile dysfunction), acne
What are some signs of Cushing's? (7)
central obesity with moon face, buffalo neck hump, skin and muscle atrophy with bruising and abdominal straie, oesteoporosis, increased BP and blood glucose, infection prone with poor wound healing
What is the 1st line test in Cushing's?
overnight dexamethasone suppression test - or low dose dexamethasone suppression test if unable to. Repeat to confirm
What is the treatment of Cushings which is iatrogenic?
withdraw/lower steroid dose where possible over 4-6 weeks (not instantly). Be aware that will not be able to respond to stress appropriately due to ACTH suppression
What is Nelson's syndrome?
When ACTH is produced in high levels (pituitary adenoma), there is increased skin pigmentation due to it being produced as POMC which also codes for melanin.
Management of Cushings disease?
remove adenoma, bilateral adrenalectomy if no obvious source
What is the prognosis like for Cushing's disease?
untreated has high vascular mortality; treated is good, but myopathy, obesity, menstrual irregularity, increased BP and osteoporosis often remain
What happens in acute adrenocortical insufficiency?
either rapid withdrawl of steroid treatment or crisis in patients who have chronic insufficiency but do not up medication on 'sick' days.
Other cause of Addisonian crisis
Massive adrenal haemorrhage
Where might a massive adrenal haemorrhage occur?
newborn, anticoagulation, DIC, septicaemia
What is Waterhouse-Fridericksen syndrome?
bilateral haemorrhage within the adrenal glands due to meningococcal septicaemia
How is an addisonian crisis managed?
Check bloods: FBC, U&Es, cortisol and ACTH, ECG, Hydrocortisone 100mg IV stat, IV fluid bolus to support BP, Monitor glucose
Symptoms of addisonian crisis
shock - increased HR, vasoconstriction, postural hypotension, oliguria, weak, confused, comatose
3 common causes of Addisons disease
Autoimmune, Infections, metastatic malignancy
Common autoimmune cause of Addisons disease
21hydroxylase adrenal autoantibodies (70%)
Common infections causing Addisons disease
TB (commonest worldwide), HIV (Kaposi's sarcoma), Fungal
Common malignancies causing Addisons disease
lung and breast cancers
When do symptoms of addisons disease start to occur?
when 90% of the gland is destroyed
How do patients with addisons present?
insidious onset with vague symptoms - weakness, fatigue, anorexia, N&V, weight loss, diarrhoea, low BP
What autoimmune diseases is Addisons associated with? (3)
T1DM, thyroid disease, pernicious anaemia
Skin colour is likely to be affected in addisons disease - TRUE/FALSE
TRUE - increased production of ACTH to try and stimulate production of cortisol and aldosterone
When might addisonian crisis occur?
due to stress i.e. infection, trauma, surgery; forgetting medication
Test to diagnose Addisons disease?
1. Short syntacthen stimulation test: plasma cortisol is measured before and 30mins after tetracosatide 250ug IM 2. test for autoantibodies and TB/malignancy when confirmed
How is the glucocorticoid deficiency managed in Addisons disease?
hydrocortisone as cortisol replacement (IV if unwell), 15-30mg.day divided into doses to mimic circadian rhythm and not after 6pm to allow sleep
How is mineralocorticoid deficiency managed in Addisons disease?
fludrocortion adjusted as necessary - monitor BP and K carefully when adjusting
What education is important for Addisons disease?
Wear identification; sick day rules (double the dose, IM if necessary), cannot stop suddenly
What is a phaeochromocytoma?
an adrenal medullary tumour derived from the chromaffin cells which secretes catecholamines
Presentation of phaeochromocytoma
labile hypertension, postural hypotension, paroxysmal sweating, headache, pallor, tachycardia, palpitations, breathlessness, constipation, anxiety, fear, weight lsos, flushing
Classic triad of phaeochromocytoma (90%)
hypertension, headache, sweating
Complications of phaeochromocytoma
caridac failure, infarction, arrhythmias, CVA, paralytic ileus
Diagnosis of phaeochromocytoma
urinary catecholamines and metabolites; hyperglycaemia, low, mild hypercalcaemia
Imaging done in phaeochromocytoma
MRI, MIBG, PET scan
Treatment of phaeochromocytoma
full a and b blockade - a (phenoxybenzamine) before b (atenolol)