Endocrine: Steroids Flashcards
What are the two steroids of interest released by the adrenal gland?
Aldosterone and cortisol
Where is the adrenal gland situated?
Above the kidney
What part of the adrenal gland is aldosterone released form?
zona glomerulosa
What part of the adrenal gland is cortisol released form?
zone fasicularis
What is the action of aldosterone?
Regulates salt and water absorption - increases salt and water retention
= indirect effect on blood pressure, raises bp.
How are the actions of aldosterone inhibited?
ACE inhibitors:
Inhibits conversion of angiotensin which prevents the stimulation of aldosterone which prevents the retention of salt and water.
Inhibiting the conversion of angiotensin also prevents vasoconstriction and therefore an increase in BP. (since angiotensin 2 is a potent VC)
Why might ACE inhibitors not be used? What is used instead?
ACE inhibitors have side effects:
Angio-oedema
Cough
Oral lichenoid
Use AT2 blockers instead.
When are larger amounts of cortisol produced?
At night, when the body is under physical and psychological stress or fighting infection.
What are the physiological effects of cortisol?
Antagonistic to insulin = type 2 diabetes
Suppress the immune system
Inhibits bone synthesis
Raises BP
List examples of therapeutic steroids and their potency in comparison to cortisol.
Hydrocortisone (1x)
Prednisolone (4x)
Dexamethasone (25x)
Beclamethasone (30x) used in asthma
What are the negative effects of therapeutic steroid use?
Type 2 diabetes Osteoporosis Gastic ulceration Hypertension Thinning of the skin Infection risk
What regulates cortisol?
ACTH produced in the anterior pituitary regulates cortisol.
What effect does cortisol in large quantities have?
Acts as aldosterone - increases salt and water retention = raises circulating volume = raises BP
What is cushing’s syndrome?
Hyperfunction of cortisol
What is a primary cause of cushing’s syndrome?
Adrenal tumours
In terms of steroid levels; how do you diagnose primary cushing’s syndrome?
Low ACTH
High cortisol
What is a secondary cause of cushing’s syndrome?
Pituitary tumour - tumour of the cells producing ACTH
In terms of steroid levels; how do you diagnose secondary cushing’s syndrome?
High ACTH
High cortisol
How do false levels of ACTH occur?
Some lung tumours produce a byproduct that is structurally similar to ACTH and mimics its effects.
What is Addison’s disease?
Hypofunction of cortisol
What is a primary cause of Addison’s disease?
Gland failure/destruction from;
Autoimmune; diabetes, thyroid issues.
Infection; TB
Infarction
In terms of steroid levels; how do you diagnose primary Addison’s disease?
High ACTH
low cortisol
SynACTHen negative
What is a secondary cause of Addion’s disease?
Pituitary failure from a pituitary tumour:
Non-Functional tumour: tumour not producing any hormones yet is growing and preventing the functional cells of the pituitary from producing ACTH.
Sheehan’s syndrome:
Dramatic drop in blood pressure causes a lack of blood flow to the pituitary gland = death of the glandular tissue.
In terms of steroid levels; how do you diagnose secondary Addison’s disease?
low ACTH
low cortisol
SynACTHen positive
What is Conn’s syndrome?
Hyperfunction of aldosterone
What can cause Conn’s syndrome
Adrenal tumour
Adrenal hyperplasia
What are the signs of Cushing’s syndrome?
Centripetal obesity: moon face and buffalo hump. Osteoporosis High blood pressure Thin skin and striae muscle weakness
What are the symptoms of Cushing’s syndrome?
Similar to diabetes mellitus; excessive thirst, urination and tiredness.
Skin and mucosal pigmentation
Depression and other psychiatric changes
Osteoporotic changes - prone to fractures
What causes skin fan mucosal pigmentation? Who is likely to get this?
Excess ACTH causes pigmentation as ACTH contains alpha melanocyte stimulating hormone.
Occurs in;
Cushings - Secondary
Addisons - Primary
What are the signs of Addison’s disease?
Vitiligo
Skin and mucosal pigmentation - primary
Postural hypotension - from salt and water depletion
Weight loss - from fluid loss
What are the symptoms of Addison’s disease?
Weight loss
Weakness
Hair loss
What occurs in an addisonian crisis?
Vomiting
Hyponatraemia - Fitting from lack of sodium
Hypotension
Eventual coma
How do you treat an Addisonian crisis?
Replacing fluid
Replacing patients sodium and potassium
How do you manage Addison’s disease?
Hydrocortisone - replaces cortisol
Fludrocortisone - replaces aldosterone (increases salt and water retention)
How do you manage Addison’s disease if there is persistent vomiting?
IV steroids and hospitalisation
How do you manage Addison’s disease if there is significant infection?
Double the oral dosage
When is steroid prophylaxis given in a patient with Addison’s disease?
When body will undergo PHYSIOLOGICAL stress
When body will fight infection
When body will undergo surgery
For what procedures is prophylaxis required?
Minor oral surgery
Spreading dental infection
In terms of steroid cover; how would you treat a patient with addison’s disease?
Since they are on steroids that act as a physiological replacements, STEROID COVER IS NOT REQUIRED because they are already on high daily dosages.
e.g. 20-30mg hydrocortisone
What should you always ask before treating a patient?
Have you been using steroids in the last 6 months.
What is the issue with prolonged steroid use?
Steroid medication taken for prolonged periods of time causes adrenal atrophy as the adrenal gland is not actively making steroids.
This means that when the steroid medication is stopped there will be sudden onset Addison’s disease leading to an Addisonian crisis because the adrenal gland takes time to gain function - will not be efficient straight away
