Adrenal Gland Pathology RM Flashcards
What is the anatomy of the adrenal gland?
Adult adrenal glands:
• 2-3cm, 1cm thick, 4-6 grams
Located in the upper pole of the kidneys Vascular supply: 12 small arteries from aorta.
Adrenal physiology - what do the adrenals produce?
Starting point for biosynthesis of steroids within adrenal glands begins with cholesterol.
- Glomerulosa - 15% of cortex ->Aldosterone (Renin –angiotensin system)
- Fasciculata- 75% of the cortex -> Cortisol & DHEA (trigger ACTH)
- Reticularis ->Androgens and estrogens (trigger ACTH)
- Medulla -> Catecholamines, adrenaline
What is the HPA axis?
One feedback loop: cortisol: from the hypothalamus -> introduction of CRH (corticotropin releasing hormone) which allows pituitary to produce ACTH -> adrenal glands produce cortisol = HPA axis.
What makes you make steroid, ACTH etc: mood, stress (infection, trauma, anaesthesis), neurotransmitters, if you aren’t sleeping properly, if you’re malnourished!
Explain the secretion of cortisol and adrenal androgens.
Circulation of cortisol and Adrenal Androgens
• Secreted and unbound
• In circulation bind to plasma proteins
• Unbound is active
• Cortisol - Free (10%), Corticosteroid-binding globulin (CBG) (75%), Albumin
What is Primary adrenal insufficiency
Damage to the adrenal glands so that they are unable to produce enough hormones.
- 80% are due to an autoimmune disease called Addison’s disease or autoimmune adrenalitis.
- One subtype is called idiopathic, or of unknown cause.
- Other cases are due to congenital adrenal hyperplasia or an adenoma (tumor) of the adrenal gland.
- Most commonly due to Waterhouse Friderichsen Syndrome (haemorrhage and infarction of the adrenals + bacterial infeciton)
What is Adddison’s Disease?
a form of primary adrenal insufficiency but it is CHRONIC- caused by:
Autoimmune adrenalitis
Tuberculosis
AIDS
What is secondary and tertiary adrenal insufficiency caused by
- pituitary ACTH defieicncy
Tertirary = hypothalamic CRH deficiency
what is the most common cause of primary adrenal insufficiency?
What are the clinical signs?
- AUTOIMMUNE ADRENALITIS (70% caused by TB)
In primary adrenal insufficiency: showing pigmented face, gums, arm, melanin spotting of the gums. AS ACTH
goes up, melanin goes up. They have lost the adrenal feedback.
• Weakness, numbness
• Skin
Mucous membrane and skin pigmentation, darkening of hair freckling, vitiligo, pigment accentuation at nipples, and friction areas, pigment concentration in skin creases and scars
Loss of weight, emaciation, anorexia, vomiting, diarrhea
Hypotension
Salt craving Hypoglycemic episodes
How do you diagnose adrenal insufficiency?
Short synACTHen test - > Given 250mcg ACTH injected IV - > Normal cortisol response: o mins: 220mmol/L 30 mins: 550 mmol/L 60 mins: 550mmol/L ------>It is difficult because insufficiency you don't rely on just one test due to circadian rhythms, they will never mount appropriate response, may get up to 300, but wont get up to 550.
If ACTH is really high and have adrenal insufficiency you know its addisons
disease and you need to put the patients on steroids
• Overnight Metyrapone testing
o DON’T need to know about this!
How do you treat someone in adrenal crisis?
Fluid resuscitation, saline and dextrose
-Patent vomiting, sick, low sugar: think they have Addisons, what do you do?
Pump saline (normally hypotensive)
And give IV hydrocortisone: 100mg IV bolus
100mg IV every 6 hours
How do you treat patients in adrenal insufficiency out of clinic?
Cortisol: hydrocortisone (10mg in AM and 5mg in PM).
Stress dosing: in fever, illness, surgery, you give double or triple the daily dose.
What are the causes of PRIMARY hyperaldosteronism?
people with primary hyperaldosteronism have a problem with the adrenal gland that causes it to release too much aldosterone.
*it may be the cause of high blood pressure in some patients.
Most cases of primary hyperaldosteronism are caused by ADRENAL ADENOMA and is most common in 30-50 year olds. = Conn’s disease
or Bilateral idiopathic adrenal hyperplasia
What are the features of hyperaldosteronism?
What are the investigations?
HYPERTENSION (up to 20% of people in community with HTN)
hypokalemia (e.g., may cause muscle weakness)- aldosterone makes you retain sodium and lose potassium
alkalosis
Investigations
high-serum aldosterone
low-serum renin
high-resolution CT abdomen
Versus someone with secondary hyperaldosteronism
secondary- cause is usually to do with RAAS system!
Hence
HTN - renin ration is decreased or NORMAL in secondary hyperaldosteronism
in primary Hyperaldosteronism: HTN -renin ratio both are raised
What is Cushing’s Syndrome?
Too much cortisol in the body- anything that makes too much hormone: pituitary tumour, ACTH produced anywhere.
Cushings disease = Pituitary tumour (80% of cushings syndrome)
