Hypofunction Flashcards
Give 4 causes of primary adrenal insufficiency?
Addison’s disease, congenital adrenal hyperplasia, adrenal TB, adrenal malignancy
Give 3 causes of secondary adrenal insufficiency?
Lack of ACTH stimulation, iatrogenic (overuse of steroids), hypothalamic/pituitary disease
Give 3 causes of acute primary adrenal insufficiency?
Rapid withdrawal of steroids, Addison crisis, adrenal haemorrhage
Give 5 causes of chronic primary adrenal insufficiency?
Addison’s disease, autoimmune adrenalitis, infections, metastatic malignancy, sacroidosis/amyloid/haemochromatosis
What is the most common cause of primary adrenal insufficiency?
Addison’s disease
What happens in Addison’s disease?
Autoimmune destruction of the adrenal cortex (90% destroyed before any symptoms)
Are autoantibodies present in Addison’s disease?
Yes, in 70% of cases
What other autoimmune diseases is Addison’s disease in association with?
Type 1 diabetes, autoimmune thyroid disease, pernicious anaemia
What is the onset of Addison’s disease?
Insidious- it manifests once there has been significant hormone losses
What does decreased mineralocorticoid in Addison’s disease result in?
K+ retention and Na+ loss (hyperkalaemia, hyponatraemia). Also volume depletion and hypotension.
What does decreased glucocorticoid in Addison’s disease result in?
Hypoglycaemia
What are some more vague symptoms of Addison’s disease?
Weakness, fatigue, anorexia, weight loss, nausea, vomiting, abdominal pain, diarrhoea
What causes increased pigmentation in Addison’s disease?
Increased ACTH
Is hyperpigmentation a feature of secondary adrenal insufficiency?
No
What may cause an Addisonian crisis?
Stress
What are symptoms of an Addisonian crisis?
Abdominal pain, vomiting, hypotension, shock, death
What is the suspicious biochemistry which would suggest a diagnosis of Addison’s?
Hyperkalaemia, hyponatraemia, hypoglycaemia
What is the stimulation test used for adrenal insufficiency?
Synacthen test
When should you measure cortisol in a synacthen test?
Before, and 30 mins after giving the ACTH injection
What would normal baseline readings be in a synacthen test?
Before ACTH= > 250nmol/l. After ACTH= > 550nmol/l.
What will the levels of ACTH be in primary adrenal insufficiency?
Raised
What will the levels of renin and aldosterone be in Addison’s disease?
Renin- high, aldosterone- low
Should you wait for a diagnosis of Addison’s disease before you give treatment?
No
What hormones need to be replaced in Addison’s disease?
Cortisol and aldosterone
What is used as cortisol replacement in Addison’s?
Hydrocortisone
How should hydrocortisone be given in Addison’s disease?
Give IV if acutely unwell, otherwise give 15-30mg/day in divided doses
Why is hydrocortisone given in divided doses?
To mimic the normal diurnal variation of cortisol
What is used as aldosterone replacement in Addison’s?
Fludrocortisone
What needs to be carefully monitored in patients on fludrocortisone?
K+ and BP
What must patients with Addison’s disease be educated about?
Sick days, wearing ID and the dangers of stopping medication suddenly
What are congenital adrenal hyperplasia syndromes?
Rare conditions of steroid synthesis, associated with enzyme defects in the steroid pathways
What is the cause of 95% of CAH cases?
21 alpha hydroxylase deficiency
How is 21 alpha hydroxyls deficiency inherited?
Autosomal recessive
What are some ways that CAH may present in boys?
Adrenal insufficiency, poor weight gain, biochemical pattern of Addison’s
How does CAH generally present in girls?
Genital ambiguity
What are some non-classical presentations of CAH in girls?
Acne, oligomenorrhoea, precocious puberty, infertility
How is CAH treated in children?
Glucocorticoid and mineralocorticoid replacement, possible surgical correction and achieving maximal growth potential
How is CAH treated in adults?
Controlling androgen excess, restoring fertility and avoiding hormone over-replacement
What are the two main causes of secondary adrenal insufficiency?
Failure to stimulate the adrenal cortex or suppression of the adrenal cortex
How can there be failure to stimulate the adrenal cortex?
Lack of CRH and/or ACTH from tumours, surgery or radiation
How can there be suppression of the adrenal cortex?
Exogenous steroid use as this suppresses release of CRH/ACTH
The clinical features of secondary adrenal insufficiency are similar to primary, with the exceptions of what?
The skin is not hyperpigmented, aldosterone production is normal
Why is aldosterone production normal in secondary adrenal insufficiency?
Aldosterone is monitored by RAAS, not ACTH
What hormone replacement is necessary for secondary adrenal insufficiency?
Hydrocortisone only
