Adrenal Cortex and Medulla Flashcards
What are some of the golden rules of endocrinology
Think in diagnostic pairs
Hormone deficiency? = Stimulation test
Hormone excess? = Suppression test
Think, examine clinically, measure hormones then image
What is primary adrenal failure (Addison’s Disease)
Adrenal itself damaged
ACTH high, low cortisol + aldosterone. Renin remain high
What is secondary adrenal failure
Problem in hypothalamus/pituitary
ACTH & Cortisol low
Normal aldosterone + renin
What is the danger of exogenous glucocorticoids
Taking tablets can shrink adrenals as it is not stimulated so once tablets taken off, go into acute adrenal crisis
What cells release renin
Juxtoglomerular
What is the action of mineralcorticoids on kidneys
Net Na+ resorption with K+/H+ loss
What are the causes of Addison’s Disease
Autoimmune adrenalitis
TB
Congenital Adrenal hyperplasia
Adrenoleukodystrophy
NB: If Abs (-) & Male, measure V. Long chain fatty acid to exclude Adrenoleukodystrophy
If Abs + FA (-), CT adrenals to exclude TB
What are the signs of adrenal insufficiency
Weight loss
Hyperpigmentation = In area’s with a lot of friction
Anaemic = Cortisol important in production of RBC
Hyponatraemia = Low serum Na
Hyperkalaemia = High serum K
Hypertension = especially postural
How do you diagnose adrenal insufficiency
Low plasma cortisol that fails to respond to exogenous ACTH
What is the treatment for adrenal insufficiency both acute and long term
Acute = IV Saline + Hydrocortisone
Long term = Replace glucocorticoids and mineralcorticoids
Sick Day Rule 1: Double oral hydrocortisone if inter-current illness with feber
Sick Day Rule 2: Inject hydrocortisone in major illness eg. trauma
What is the difference between Cushings Syndrome/Disease
Syndrome = in general for too much glucocorticoid Disease = pituitary tumour that overproduces glucocorticoids
How do you define Cushings
Constellation of symptoms and signs that reflect prolonged and inappropriately high exposure of tissue to glucocorticoids
What are the causes of Cushings
Exogenous corticosteroids
Pituitary tumour
Adrenal adenoma/carcinoma
Ectopic ACTH syndrome eg. Small cell ling carcinoma
What are the signs/symptoms of Cushings
Muscle dystrophy Striae in skin Central obesity Facial fullness Bruising due to thinning of skin
How is Cushings diagnosed
24hr urinary free cortisol
Dexamethasone suppression test
Late night salivary cortisol. Cortisol should be undetectable
Measure ACTH to determine wether dependent or not
Pituitary or ectopic
Image
How is Cushings treated
Surgery
Drugs
- Metyraprone = block adrenal enzymes so stop cortisol production
- Mitotaine = destroy adrenal tissue
What are some of the effects of glucocorticoids on the system
Hypertension
Stop menstrual cycle + gonadal failure
Immunosuppression
Peripheral insulin resistance
What is Conns disease
Primary aldosteronism
Characterised by hypertension & hyperkalaemia
What are the causes of Conns disesase
Adrenal adenoma
Bilateral adrenal hyperplasia
How do you diagnose Conns disease
Suppression of plasma renin activity
How do you treat Conns disease
Surgery for adenoma
NB: Ineffective for hyperplasia
Drugs eg. Eplerenoma
What is a phaeochromocytoma
Tumours of chromaffin tissue secreting NAd
So excess catecholamines
What are the symptoms of phaeochromocytoma
Headache
Sweating
Palpitations
What is the treatment for phaeochromocytoma
Alpha or beta blockers
Take out mass
What is the difference between adenoma and carcinoma
Adenoma = benign. Fatty. Tumour density low.
Carcionoma = malignant. Not fatty
Larger tumours are more likely to be malignant
What must you not do with phaeochromocytoma
Needle it as this will release catecholamines causing massive hypertension
It is difficult to measure catecholamines, so what do we measure
Ad/NAd = short half lives
Broken into VMA which we measure
In a case of adreno incidentaloma what do you have to think about
Exclude primary aldosteronism, cushings, adrenal androgen xs, phaeochromocytoma
Determine if malignant
