Steroids Flashcards
What are the main adrenal issues
Destruction of adrenal tissue - Addison’s disease
Excess adrenal action - Cushings disease
Therapeutic corticosteroids causing suppression of adrenal action and adverse effects
What are the 3 areas of the adrenal gland and what do they each produce
Zona glomerulosa - aldosterone
Zona retiuclaris - adrenal androgens
Zona fasciculata - cortisol
How is the adrenal gland regulated
Hypothalamus released corticotrophic hormone which is passed to the anterior pituitary through the venous plexus causing the pituitary to secrete ACTH
ACTH will pass to the adrenal cortex where it will stimulate production of a variety of hormones including cortisol
Cortisol will feedback both to the pituitary and the hypothalamus
What is the function of aldosterone
Regulates salt and water through the renin-angiotensin system
Enhances Na+ reabsorption and K+ loss
Indirect affect on blood pressure
Which drugs inhibit aldosterone
ACE inhibitors
AT2 blockers - block angiotensin receptor
What are the functions of insulin
Antagonist to insulin - promoting gluconeogenesis and fat and protein breakdown
Lowers the immune reactivity of the body
Inhibits bone synthesis
Raises blood pressure
Give examples of therapeutic steroids and their cortisol equivalents
Hydrocortisone - 1 Prednisolone - 4 Triamcinolone - 5 Dexamethasone - 25 Beclamethasone - 30
What are the positive effects of therapeutic steroids
Enhanced glucocorticoid effect - immunosuppression and reduced inflammatory response
Enhance mineralcorticoid effect - salt and water retention
What are the adverse effects of therapeutic steroids (just name some)
Hypertension Type 2 diabetes Osteoporosis Increased infection risk Peptic ulceration Thinning of the skin Easy bruising Cataracts and glaucoma Hyperlipidaemia Atherosclerosis Increased cancer risk Psychiatric disturbance
What can cause hyperfunction of the adrenal gland
Glucocorticoids - Cushing’s syndrome:
-adrenal tumour - primary
-pituitary tumour - secondary
Aldosterone - Conn’s syndrome - adrenal tumour
What can cause hypofunction of the adrenal gland
Addison’s disease - primary
Pituitary failure - secondary
Who is most affected by Cushing’s syndrome
Female to male ratio of 4:1
What are the different causes of Cushing’s syndrome
Cushing’s disease - pituitary ACTH tumour, 70% of patients
Adrenal adenoma or hyperplasia
Ectopic ACTH production - some lung tumours
What are the symptoms of Cushing’s syndrome
Diabetes mellitus features Poor resistance to infection Psychiatric disorders Hirsutism Skin and mucosal pigmentation Amenorrhoea, impotence and infertility
What are the signs of Cushing’s syndrome
Centripetal obesity - moon face and buffalo hump Hypertension Thin skin and purpura Muscle weakness Osteoporotic changes and fractures
How may a Cushing’s patient present to the dentist
Oral fungal infection due to the high levels of corticosteroid reducing the appropriate immune response to an invader
Describe the appearance of a patient with Cushing’s syndrome
Typical moon face and centripetal obesity
Arms and legs are thin but face and trunks are large
Stretching of the skin over the fat being deposited on the trunk will result ion abdominal straie
Fat enlargement around the back of the neck - buffalo hump
How may ACTH cause pigmentation of the skin and mucosa
Similarities in sequence between ACTH and MSH - melanocyte stimulating hormone - means that high ACTH levels will stimulate pigment cells
What are the primary and secondary causes of adrenal hypofunction
Primary (Addison’s disease) - autoimmune gland destruction, infection and infarction
Secondary (Pituitary failure) - compression from other adenoma or Sheehan’s syndrome
What are the causes of Addison’s disease
TB - now rarer but still the biggest cause worldwide
Autoimmune adrenalitis - 90% of cases, organ specific autoimmune disease
What are the signs of Addison’s disease
Postural hypotension - absence of aldosterone causes salt and water depletion
Weight loss
Lethargy
Hyperpigmentation - not in secondary, only if ACTH levels rise
Vitiligo
What are the symptoms of Addison’s disease
Weakness
Anorexia
Loss of body hair (females)
What investigation results suggest a patient has Cushing’s syndrome
High 24 hour urinary cortisol excretion
Abnormal dexamethasone suppression tests - feedback suppression of cortisol via ACTH as dexamethasone by negative feedback should suppress ACTH production
CRH tests - Cushing’s disease show rise in ACTH with CRH
What investigation results suggest a patient has Addison’s disease
High ACTH levels as the pituitary is lacking the feedback inhibition from cortisol, so tries to stimulate the gland more by increasing ACTH output
Negative synACTHen test as patient has autoimmune destruction
