Addisons disease

Question 1

Definition

Answer 1

Primary adrenocortical insufficiency

When there is complete destruction of the entire adrenal cortex

Addisons disease leads to a marked lack of glucocorticoid and mineralocorticoid from the adrenal cortex
– symptoms won’t manifest until at least 90% of the adrenal cortex has been destroyed

Question 2

Aetiology

Answer 2

More than 90% of cases are from destruction by organ-specific
So they are antibodies produced against adrenal cells
Associated with other disease:
– autoimmune thyroid disease
– ovarian failure
– pernicious anaemia
– Type 1 diabetes mellitus

Rarer causes:
– adrenal gland TB
– surgical removal
– haemorrhage
– malignant infiltration
– also radiation treatment for malignant infiltration

Question 3

Epidemiology

Answer 3

Rare disease (incidence of 1 in 100’000 people)

Most cases present in young to middle aged adults

Women are affected more than men

Question 4

Clinical presentation

Answer 4

Insidious presentation with non specific symptoms (this makes the diagnosis challenging)

– weight loss is prominent and the main symptom you will see
– lethargy
– tiredness
– anorexia
– weakness
– nausea
– vomiting
– diarrhoea
– tachycardia (due to decreased mineralocorticoids)
– low grade fever
– loss of hair
– cachexia
Loss of libido seen more in women (androgens)

Question 5

Pathophysiology

Answer 5

Hypothalamus releases CRH, which targets the anterior pituitary gland to release ACTH, which will act on the adrenal gland to release mineral corticoids (aldosterone) and glucocorticoids (cortisol)
– cortisol will have a negative feedback on the hypothalamus, meaning it will communicate with it and tell it to stop releasing CRH

90% of cases are autoimmune antibody attacks on the adrenal cells:
– this is where there is damage to the adrenal gland meaning there is a decreased release of mineralocorticoids and glucocorticoids

Decrease in mineralocorticoids:
– will decrease the sodium uptake which means there will be a decreased water uptake, leading to a decreased BP due to an decreased blood volume, so tachycardia will occur

Decrease in glucocorticoids:
– may cause generalised skin pigmentation and weight loss

Decreased libido in women:
– due to a decreased release of androgens from the adrenal cortex, this has more of an affect on women, leading to them having a decreased libido