Adrenal Disorders Flashcards
Adrenal failure
Addison’s disease
Excess cortisol
Cushing’s syndrome
How many central veins do the adrenal glands have?
one central vein despite many arteries
What lies next to the left adrenal gland?
spleen
easily damaged during left adrenalectomy (high vasculature and proximity)
patient must be immunised with HIB and pneumovax (against strains of Streptococcus pneumococcus)
How are hormones from adrenal gland mobilised?
arteries pass through cortex and pick up hormones made by adrenal gland
these are then delivered to the central vein
What are the 3 main hormone groups?
peptides (prolactin, somatotrophin, ACTH)
steroids (testosterone, cortisol)
amines (adrenaline)
What determines the product steroid hormones derived from C27 cholesterol?
enzymes present in the target tissue
each zone of adrenal cortex has different enzymes
What is the pathway for aldosterone production?
pregnenolone
progesterone (3)
ONLY IN ADRENALS (contain 21-hydroxylase enzyme needes)
11 deoxycorticosterone (21)
corticosterone (11)
aldosterone (18)
What is the pathway for cortisol production?
17 OH pregnenolone
progesterone
17 OH progesterone (17)
ONLY IN ADRENALS (contain 17-hydroxyprogesterone enzyme)
11 deoxycortisol (21)
cortisol (11)
What is the pathway for oestrogen production?
progesterone 17 OH progesterone androstenedione converted further in gonads sex steroids androgens oestrogens
What is POMC?
precursor for ACTH
it is cleaved into smaller peptides (ACTH, MSH and endorphins)
high ACTH also inappropriately tanned (MSH high too)
Describe the cause of Addison’s disease
Clinical features
primary adrenal failure
- autoimmune disease destroys adrenal cortex
- tuberculosis of adrenal glands
INCREASE PIGMENTATION - Pituitary secretes excess ACTH to compensate for lack of cortisol so increases MSH
Low blood pressure as adrenals do not make aldosterone/cortisol
Autoimmune vitiligo may coexist
Salt loss
Eventual death
What the most common worldwide and UK causes of primary adrenal failure?
worldwide - TB of adrenal glands
UK - autoimmune disease destroys cortex
What is the urgent treatment plan for Addisonian crisis?
rehydrate with normal saline
give dextrose to prevent hypoglycaemia which could occur due to glucocorticoid deficiency
give hydrocortisone/glucocorticoid medication
What are the biological effects of excess cortisol and cause?
impaired glucose tolerance(diabetes) - increased blood glucose []
weight gain, thin skin, easy bruising, striae/stretch marks (increase fat, lose protein)
proximal myopathy - weakness of large muscles
mental changes - depression as steroids affect CNS
hypertension
fat redistribution (centripetal obesity - lemon on sticks)
inter-scapular fat/buffalo pad
hirsutism/acne - zona reticularis secretes more testosterone
immunosuppression (TB reactivation)
What is Cushing’s Syndrome?
excess cortisol
also excess of any other glucocorticoid
- take steroids by mouth
- pituitary adenoma producing too much ACTH (Cushing’s Disease)
- Ectopic ACTH (lung cancer cells can produce ACTH)
- adrenal adenoma/carcinoma
What is the difference between Cushing’s syndrome and disease?
syndrome = collection of symptoms with any cause disease = cause is PITUITARY ADENOMA
What are the side effects of steroids similar to ?
Cushing’s syndrome
hypertension, diabetes, osteoporosis, reactivation of infection, easy bruising, poor wound healing, thin skin
What is Conn’s syndrome?
aldosterone producing adenoma tumour of zona glomerulosa - retain Na and lose K - hypertension - oedema - low blood K
What is made by the zona reticularis?
testosterone
How is progesterone formed from cholesterol?
cholesterol side chain cleaved
form pregnenolone
this is oxidised to give progesterone
What is the cause of bitemporal hemianopia?
optic nerve chiasm compression (where information decussates across the optic nerve)
confirms pituitary tumour >10mm (macroadenoma)
middle and outer areas of retina not working
How to ensure no child whilst breastfeeding?
very high prolactin
inhibits FSH/LH
How to treat pituitary tumour?
if acromegaly/cushings operate if prolactinoma do not operate - use dopamine agonist to cause tumour to shrink - cabergolin/bromcriptine - may become resistant
