Addison’s Disease

Addison’s Disease/Primary adrenocortical insufficiency/Adrenal hypofunction:
Rare – maybe 8/1000000. Originates in adrenal gland (secondary type originates outside). Characterised by decreases secretion of mineralocorticoids, glucocorticoids and androgens.

Aetiology:
70-80% due to idiopathic hypertrophy of adrenal cortex – probably autoimmune (symptoms occur when 90% of gland destroyed).
Other causes – granuloma (eg TB), tumour, tuberculosis, amyloidosis, inflammatory necrosis, haemorrhage into gland.

Inadequate aldosterone  disturbances of sodium, potassium and water metabolism.
Inadequate cortisol  abnormal metabolism of fat, protein and carbohydrate metabolism.

Clinical features:
May be insidious or acute.
Weakness, weight loss, fatigue, nausea, vomiting, hypoglycaemia, hypokalaemia, orthostatic hypotension, low metabolic rate, increased insulin sensitivity, hypoglycaemia, increased pigmentation (appears like diffuse tanning/bronzing, due to MSH from pituitary), joint and muscle pains, confusion, craving salty foods

Adrenal crisis – profound asthenia, abdominal pain, weakness, dehydration, peripheral vascular collapse, renal shutdown. Often precipitated by acute infection, trauma, surgery in those with adrenal hypofunction – stores of glucocorticoids are exhausted..

In children – behavioural problems; in newborn  gravely ill (tachycardia, hypotension, tachypnoea, ever, cyanosis, cold and clammy skin)

Treatment:
Glucocorticoid replacement therapy (lifelong).
Restoration of fluid and electrolyte imbalance (high sodium, low potassium, fluids)
If adrenal crisis  fluid replacement, glucose, IV hydrocortisone
In children, weight gain and poor growth can be consequence of long term corticosteroid replacement.