Addison's disease Flashcards
What is Addison’s disease on a postcard?
ie what’s the thing that’s missing/excessive
Primary adrenal insufficiency
(aldosterone and cortisol .: lacking most importantly)
Primary - problem with the adrenal gland itself
Anatomy of the adrenal gland - name the layers
Outer to inner Cortex: 1 - zona glomerulosa Cortex: 2 -zona fasciculata Cortex: 3 -zona reticularis Medulla
large functional reserve - so if sympoms are present - a lot has probs been destroyed
Zona glomerulosa; what hormone does this produce, and what are its effects; where?
Aldosterone - Decrease potassium, increase sodium in the blood
This increases blood volume and pressure
Secreted in response to renin - then it activates Na/K pumps at the distal convoluted tubule of the nephron and the ATPase which pumps H+ ions out of the cell into the urine
zona fasciculata; what hormone does this layer produce and what makes it get released?
cortisol (etc) - released in times of stress (physical/emotional).
Hypothalamus releases corticotropin-releasing hormone
This stimulates the anterior pituitary gland to secrete ACTH (adrenocorticotropic hormone)
Which then stimulates the Z.F. of adrenal gland to secrete cortisol
Cortisol - what does it cause?
Gluconeogenesis -from amino acids (from protein) and from free fatty acids (from fat)
So increases glucose in blood.
Also anti-inflammatoy
Levels highest in the morning then fall throughout the day
zona reticularis - what does it make
A precursor to testosterone
seems to be stimulated by ACTH too - but peeps are unsure
causes of addisons disease
Autoimmune
tuberculosis (spread from lungs)
metastatic carcinoma
symptoms of addisons disease
Hyperkalaemia, hyponatraemia, hypovolaemia, metabolic acidosis
> nausea, vomiting, fatigue, lightheadedness (aldosterone lost)
Weak, tired, disorientated (even when challenged) (cortisol lost)
hyperpigmentation (especially in sun exposed areas)
usually progresses very slowly - unless a stressor appears and the required aldosterone/cortisol cant be made (addisonian crisis)
Why does hyperpigmentation occur in Addison’s disease?
Low cortisol in the blood means that the a. pituitary glad produces more proopiomelanocortin (the ACTH precursor). This is also a precursor for melanocyte-stimulating hormone - which causes hyperpigmentation in addisons
who would be affected more if the zona reticularis was destroyed - men or women? why?
women - men have their testes which make most of their testosterone anyway
women may lose pubic hair and sex drive
Addisonian crisis - signs
After major stressor - surgery, infection etc
Malaise/fatigue
low grade fever
Pain in abdomen/muscle cramps
vomiting and diarrhoea ->low BP/ dehydration ->loss of consciousness ->death
Diagnosis of addisons
ACTH stimulation test SYNthetic ACTH (synacthen) is given to patient then cortisol is measure 30mins later
Treatment of addisons
Cortisol, aldosterone and androgens are given to patient
hydrocortisone (take more when unwell etc), Fludrocortisone,
Exogenous steroids could cause…
secondary adrenal insufficiency
It’s not important, but for the lols:
what is Waterhouse-Friderichsen syndrome.
adrenal gland failure due to bleeding into the adrenal gland. It is usually caused by severe meningococcal infection or other severe, bacterial infection. Symptoms include acute adrenal gland insufficiency, and profound shock
can also be caused by sudden rise in BP
