Adrenal insufficiency Flashcards
What does adrenal insufficiency refer to
A reduced production of the hormones secreted by the adrenal cortex
Causes of primary adrenal insufficiency include
Diseases affecting the adrenal cortex such as Addison’s disease
Causes of secondary adrenal insufficiency include
Pituitary/ hypothalamic disease or long term steroid use and suppression of the hypothalamic pituitary adrenal (HPA) axis
What is Addison’s disease
an isolated autoimmune adrenal insufficiency which occurs predominantly in males and females in the 3rd decade
Thereafter, predominantly females
What is the most common cause of primary adrenal insufficiency
autoimmune adrenalitis
What is the first evidence of autoimmune adrenal insufficiency
an increase in plasma renin activity, suggesting that the son glomerulosa failure and reduction in aldosterone occur first
What causes APS (Autoimmune adrenal insufficiency) type 1
Autosomal recessive disorder caused by mutations in the AIRE gene which encodes a nuclear transcription factor
What is characteristic of APS type 1
chronic mucocutaneous candidiasis and hypoparathyroidism followed by Addisons
What is APS type 2
an autosomal recessive, dominant or polygenic manner that is characterised by Addison’s disease, autoimmune thyroid disease and diabetes mellitus
What are some of the causes of primary adrenal insufficiency
Autoimmune
Infection - TB, fungal, cytomegalovirus
Infiltration - metastases, lymphoma, amyloidosis, haemochromatosis
Infarction - due to thrombosis caused by thrombophilia
Haemorrhage - meningococcal septicaemia , anticoagulants
What is the second most common cause of Addison’s disease
TB
Name the groups of patients that are likely to have adrenal insufficiency secondary to HPA axis suppression by longterm glucocorticoid use
Those who have received a glucocorticoid dose equivalent to or more than 20mg of prednisolone per day for more than 3 weeks
those who have received an evening or bedtime dose of prednisone or more than a few weeks
those who have a Cushingoid appearance
How does adrenal iris most commonly present as
Shock
What patients might an acute adrenal crisis be seen in
those with previously undiagnosed adrenal insufficiency who have been subject to acute stress or illness (e.g. infection)
those with known adrenal insufficiency who have not increased their steroid does during and infection or other illness, or who have been vomiting
Describe the clinical presentation of primary adrenal insufficiency
Malaise, fatigue, weakness, anorexia, weight loss
Nausea, vomiting, abdo pain, diarrhoea
postural hypotension, improved BP in hypertensive patients
Hyponatraemia, hyperkalaemia, hypoglycaemia, hypercalcaemia
Hyperpigmentation
Impairment of memory, confusion, depression
What can be given to cause the hyerpigmentation to disappear
A few months of treatment with glucocorticoids
What do vitiligo resit from
autoimmune destruction of dermal melanocytes
What are some of the differences in the presenting complaint of secondary and primary adrenal insufficiency
Secondary - no hyperpigmentation
No dehydration or hyperkalaemia
GI symptoms are less common
Hypoglycaemia is more common
What would be seen in a blood test at presentation
Hyponatraemia Hyperkalaemia Acidosis High urea Mild hypercalcaemia eosinophilia Hypoglycaemia (rare in adults)
When should cortisol be measured
9am
What level of cortisol is diagnostic of adrenal insufficiency
9 am serum cortisol level of less than 100nmol/L
What is the next step for those who have a 8-9am cortisol level of 100-550nmol/L
short ACTH stimulation test –> 250g of synthetic ACTH is given intramuscularly and serum cortisol is measured at time 0, 30 mins and 60 mins
What is a normal response to ACTH stimulation test
Peak cortisol of over 550nmol/L
What sort of test may be used to distinguish primary from secondary adrenal insufficiency
Prolonged ACTH stimulation test
What other conditions should patients with autoimmune adrenal failure also be investigated for
Diabetes mellitus: fasting glucose
Thyroid disease: Free T3/T4 and TSH
parathyroid dysfunction: calcium and phosphate
Pernicious anaemia: parietal cell antibodies
Primary gonadal failure: LH, FSH, either testosterone or estradiol
What are the investigations required in an Addisonian crisis
Blood for serum cortisol ACTH, renin and serum urea and electrolytes should be drawn and therapy started immediately
What are the 3 main treatments initially for an Addisonian crisis
Fluids - 1-3L of saline IV with IV dextrose if hypoglycaemic
Glucocorticoids: dexamethasone IV
Underlying cause - infection etc.
Why is dexamethasone preferred to hydrocortisone
Not measured by serum cortisol assays
Describe the long term treatment for adrenal insufficiency
Glucocorticoid replacement: hydrocortisone - 1-mg am, 5mg noon and 5mg evening
doubling this dose at times of intercurrent illness
Emergency supply of IM hydrocortisone - times of vomiting on their way to hospital
steroid card and medic alert bracelet
What other replacements may be required for patients with adrenal insufficiency
Mineralocorticoid replacement (fludrocortisone) Androgen replacement
What should we do for patients who have a withdrawal from glucocorticoids
The dose must be reduced gradually
