Cushing's and Addison's Flashcards
Adrenal gland layers
Outer- zona glomerulosa
Middle- zone fasciculate
Inner- zona reticularis
Zona glomerulosa function
Produces mineralcorticorticoids
E.g. aldosterone
Aldosterone function
Salt: water balance
Targets distal convoluted tubule and collecting duct of nephrons
Causes Na+ to leave tubules
Causes water to leave tubules again, reabsorbed into body
NET effects- dec urine vol, inc blood pressure
Zona fasciculata function
Produces glucocorticoids
E.g. cortisol
Cortisol function
Main stress hormone
Fight or flight
Release promotes gluconeogenesis from fat and protein
In doing so, glucose released into blood, causing blood sugar levels to inc providing energy required to deal with threatening situations
Hypothalamic-pituitary-adrenal axis
System by which glucocorticoid hormones are managed
Hypothalamic-pituitary-adrenal axis stages
Stressful stimuli
Corticotropin releasing hormone released from hypothalamus
Adrenocorticotrophic hormone released from ant pituitary
Cortisol released from zona fasciculate of adrenal cortex
-ve effect of chronic stress
Extended release of cortisol
Lack of energy
Hypertension
Migraines
Anxiety or depression
Zona reticularis function
Produces androgens
Testosterone-like hormone
Key role in growth, reproduction and development
Adrenal medulla
Synthesises modified amino acid hormones (class of non-steroid)
Medulla inner region of organ/tissue
Contains chromatin cells- secretes catecholamines
Secrete following cat
- Epinephrine (adrenaline)- 80%
- Norepinephrine (noradrenaline)- 20%
Catecholamines
Modified amino acid hormone (non-steroid)
Secreted by chromatin cells
Types- epinephrine (adrenaline), norepinephrine (noradrenaline)
Epinephrine and norepinephrine role in fight or flight
Released in response to perceived threat, a dangerous situ, excitement or stress
Prime the body for rapid response to threat
Breathing rate inc
Cardiac output inc
Inc breakdown of fats for energy
Adrenal gland disorders- primary causes
Tumours- typically benign
Genetics- autoimmune disorders
Certain medications
Infection of adrenal glands, hypothalamus and pituitary
Cushing’s syndrome
Rare disorder resulting from overproduction of cortisol from zona fasciculata and over production of aldosterone from zona glomerulosa of cortex
Hypersection of cortisol from zona fasciculate of cortex produces symptoms
Cushing’s symptoms- hyper secretion of glucocorticoids
High cortisol
Inc lipolysis (breakdown of fat)
Inc break down of protein
Hyperglycaemia
Obesity
Redistribution of fat- upper back, chest, face, abdomen
Symptoms of Cushing’s- hyper secretion of aldosterone
o High aldosterone
o Water retention
o Inc blood volume
o Dec urine output
o Muscle weakness (typically in arms and thighs)
Symptoms of Cushing’s- hyper secretion of androgens
o Development of male characteristics in females
o Cessation of menstrual cycle
Symptoms of Cushing’s- skin changes
o Thin and wrinkled
o Inc ease of bruising
o Deep purple stretch marks
o Poor ability to heal
o Hirsutism- condition in which women develop male-like growth of hair on face, chest, back and arms
Symptoms of Cushing’s- bee
o Dec libido- 90-100%
o Lethargic, depression, anxiety
Other symptoms of Cushing’s
o Impaired glucose tolerance/diabetes
o Memory loss and trouble concentrating
o Osteopenia- dec bone density resulting in weakening of bones
o Adrenal or pituitary tumour
Arteriosclerosis
Cushing’s cause
- Adenoma of ant pituitary- inc ACTH causes hypersecretion of glucocorticoids
- Adrenal gland tumours- hyperaldosteronism (over-production of aldosterone)
- Ectopic- rare. As a result of a tumour which is not in pituitary gland, causes cortisol to be released from zona fasciculata of adrenal cortex
- Long term use of cortisol-like steroids
Cushing’s diagnosis
Cortisol measurement- salivary cortisol levels, urinalysis
Dexamethasone suppression test
Presence of tumours- ant pituitary and adrenal gland tumours detected via imaging- CT or MRI
Dexamethasone suppression test process
Use synthetic steroid (dexamethasone) to check if ACTH secretion by ant pituitary can be suppressed
Dexamethasone binds same hormone receptor as cortisol
In healthy people- dexamethasone will reduce ACTH secretion, levels will be low
In those with Cushing’s- ACTH will be abnormal
Cushing’s treatment
- Depends on cause
- Steroid medication= reduce intake
- Tumour= removal
Addisons disease
Rare disorder which results from under production of cortisol from zona fasciculate and under production of aldosterone from zona glomerulosa
Addisons symptoms- hypo secretion of glucocorticoids
Low cortisol
Weight loss
Dec appetite
Addisons symptoms- hypo secretion of aldosterone
Low aldosterone
Inc urine output- loss of Na+ (tend to crave salt_, risk of dehydration
Dec blood pressure- inc urea, bradycardia (<50bpm), muscle weakness
Addisons symptoms- skin changes
o Dehydrated/prone to cracking
o Hyperpigmentation
o Impaired healing- mouth ulcers
Addisons beh symptoms
o Lethargic
o Fatigue
o Dep and anxiety
Adrenal crisis- Addisons
Can develop or worsen over time. Symptoms- very low blood sugar/pressure, severe dehydration, vomiting. Medical emergency
Addisons cause
- Autoimmune- body attacks cortex of adrenal glands
- TB- bacterial infection that can affect any part of body, mainly- adrenal glands, bones, nervous system. Damages adrenal cortex which interrupts secretion of hormones including cortisol and aldosterone
- Long term use of cortisol-like steroids
Addisons diagnosis
- Initial visual and stats- medical Hx reviewed alongside weight records to identify any unexpected weight loss, blood pressure low, skin discolouration
- Cortisol measurements- salivary cortisol levels, urinalysis
- ACTH measurements- high levels
- Synacthen test- synthetic version of ACTH, blood test taken before and after injection, high synacthen and low cortisol and/or cortisol indicates +ve
- Presence of tumours- CT/MRI
Addisons treatment
- Restoring adrenal function
- Depends on cause
- Hormone replacement medication if autoimmune
- Glucocorticoids
- Surgeyr to remove tumour
