Adrenal ☺️ Flashcards
Gross structure of the adrenal gland
- hormone secreted
- adrenal hormone release mechanism
CRH => ACTH (derived from POMC) => cholesterol conversion to steroids
Zona glomerulosa, aldosterone
Zona fasciculata, cortisol
Zona reticulata, androgens
Medulla => chromaffin cells, NA/A
Mineralocorticoid
- function
- secretion regulation
- state in blood, T1/2
Stimulates ENac, NaKATPase in DCT, CD => increased BP, BV, K excretion
- spironolactone (K sparing)
- short T1/2 => less bound to Albumin, CBG
Stimulated by
-Ang2, high K, ACTH
Conn’s syndrome
- pathophysiology
- presentation
- investigations
- management
Idiopathic, adrenal adenoma => hyperaldosteronism
HTN, low K (muscle weakness), alkalosis
High Ald:low renin
CT abdo, adrenal vein sampling => differentiate unilateral/bilateral
Adrenal adenoma => surgery
Bilateral hyperplasia => spironolactone/eplerenone for men
Glucocorticoid
- function
- secretion, regulation
- state in blood, T1/2
- affinity for GC and MC receptors
Upregulate arteriole a1 rec => support RAAS
Increases osteoclastic activity => osteoporosis
Increased insulin resistance => hyperglycemia
Increased gluconeogenesis, lipolysis, proteolysis
Decreased inflammatory, innate immunity action
- long T1/2 => highly bound to CBG
- diurnal secretion, peaks when waking and eating
- stress
Cortisol has high affinity for MCR Aldosterone sensitive tissue -cortisol => cortisone Liver, adipose, muscle -cortisone => cortisol
Cushings syndrome
- pathophysiology
- presentation
- investigations
- management
ACTH dependent -hyperactive pituitary tumour/ectopic production (small cell lung cancer) ACTH independent -steroid use -adrenal adenoma/cancer LOSS OF DIURNAL RHYTHM
Moon red face Acne, hirsuitism Buffalo pads, obese, striae Proximal muscle wasting, easy bruising Infection prone Oligo/amenorrhea DM, HTN
High 24 hour urinary free cortisol
Dexmeth suppression => differentiate between causes
Surgery => remove adrenal, hydrocortisone replacement
Inhibit steroid synth => metyrapone/ketoconazone
Inhibit ACTH release => pasireotide, cabergoline
Inhibit GC rec => mifeprestone
Hypoadrenalism
- causes
- pathophysiology
- presentation
- investigations
- management
Primary -TB, HIV, APS, metastasis -Waterhouse Friderischsen (bacterial infection causes adrenal vessel rupture) -Addisons -abrupt discontinuation of steroids Secondary -pituitary disorders
Fatigue, muscle wasting, weight loss
N+V, dehydration, salt craving => hypotension
Hyperpigmentation (only in primary)
Random cortisol => low
Synacthen => primary or secondary cause
Adrenal AB
Low Na, high K, low aldosterone
MC, GC replacement => hydro/pred/fludro
-higher doses needed for surgery
What is adrenal failure
How would you manage this medical emergency
Collapse, shock, pyrexia
-lack of cortisol and aldosterone
Low BP, Na, glucose
High K
NEEDS NA AND HYDROCORTISONE
-fluid resus
Phaeochromocytoma
- causes
- pathophysiology
- presentation
- investigations
- management
NA/A secreting tumour, linked to
-MEN2(medullary thyroid cancer), Von Hippel-Lindau
HTN
Headache, palpitaion
Sweating, anxiety
24hr urine metanephrine/catecholamine
a blocker (phenoxybenzamine), b blocker (propanolol) stabilisation Followed by surgery
Describe how the sex hormones are made
Effect of excess androgen on premenopausal women
How do amounts of estrogen and androgen change post menopuase
Androstenedione => estrogen and testosterone
Excess androgen => hirsuitism, virilisation
Ovary produces less O
- peripheral conversion in adipose
- more adipose => smaller decline in estrogen
CAH
- common causes
- pathophysiology
- presentation
- management
Autosomal recessive
- most common - 21hydroxylase deficiency => low cortisol, aldosterone
- ACTH, adrenal hyperplasia to compensate => excess androgens
Female virilisation
Precocious puberty in males
Salt wasting
GC, MC replacement
Multiple endocrine neoplasia
- inheritance
- characteristics of each type
AD MEN 1 gene -parathyroid - hypercalcemia -pituitary -pancreas
MEN 2a - RET oncogene
- parathyroid
- phaeochromocytoma
- medullary thyroid cancer
MEN 2b - RET oncogene
- phaeochromocytoma
- medullary thyroid cancer
- marfanoid, neuromas
