Adrenocortical Hypofunction Flashcards
what are some causes of acute primary adrenocortical insufficiency
rapid withdrawal of steroid treatment
massive adrenal haemorrhage
- newborn, anticoagulant treatment, DIC, septicaemic infection
what can occur as a crisis in patients with chronic adrenocortical insufficiency due to stress
acute adrenocortical insufficiency
eg in Addison’s patients after infection or not increasing dose of steroid treatment
DIC
disseminated intravascular coagulation
widespread activation of the clotting cascade
waterhouse-friderichsen
causes acute adrenocortical insufficiency
adrenal gland failure due to bleeding into the adrenal glands, commonly caused by severe bacterial infection eg Neisseria meningitides
addison’s disease
destruction of the adrenal cortex leads to glucocorticoid and mineralocorticoid deficiency
signs are capricious
reduced cortisol levels lead to increased CRH and ACTH production
what is the most common cause of primary adrenal insufficiency
addison’s
causes of Addison’s
80% are due to autoimmunity
(autoimmune adrenalitits results from the destruction of the adrenal cortex by antibodies, 21-hydroxylase as the common antigen)
infection: TB, fungal, HIV
metastatic malignancy: breast and lung
unusually: amyloid, sarcoidosis, haemochromatosis
what can be used as a marker in autoimmune causes of Addison’s
21-hydroxylase
autoantibodies present in 70%
what is associated with autoimmune causes of Addison’s
other autoimmune diseases eg T1DM, autoimmune thyroid disease, pernicious anaemia
what fungal infection can cause Addison’s
histoplasma
what is often seen in patients with HIV causing Addison’s
mycobacterium avium complex
kaposi’s sarcoma
Kaposi’s sarcoma
mostly seen in people with advanced HIV infection, causes patches of abnormal tissue to grow under skin and in lining of organs etc
onset of Addison’s
delayed presentation and insidious onset
signs and symptoms are only present once 90% of the gland has been destroyed
often non-specific signs and symptoms
clinical features of Addison’s: vague symptoms
weakness
fatigue
anorexia
nausea and vomiting
weight loss, diarrhoea
pigmentation
postural hypotension
what mood changes are seen in Addison’s
depression, psychosis and low self esteem
describe the pigmentation seen in Addison’s
especially of new scars and palmar creases
increased ACTH stimulates the production of POMC
why is there postural hypotension in Addison’s
due to decreased mineralocorticoids, is common even when supine BP is normal
there is K retention and Na loss - hypovolaemia
mineralocorticoid deficiency also results in hyperkalaemia, hyponatraemia, volume depletion and hypotension
what are the results of decreased glucocorticoids in Addison’s
hypoglycaemia (cortisol is a stress hormone that causes blood glucose levels to rise)
what are the symptoms of an addisonian crisis
occur due to stress (trauma, infection, surgery)
causes vomiting, abdominal pain, hypotension, shock and death
management of an Addisonian crisis
give 100ml IV hydrocortisone
IV fluid bolus to support BP
monitor BG and check for hypoglycaemia
diagnosis of adrenal insufficiency
suspicious biochemistry - decreased Na and increased K, hypoglycaemia
short synACTHen test
ACTH levels
renin/aldosterone levels
adrenal autoantibodies
short synACTHen test to diagnosis adrenal insufficiency
small amount of ACTH injected (IV/IM) and cortisol response measured
normal: baseline >250nmol/L and post ACTH >550nmol/L
ACTH levels in adrenal insufficiency
should be increased
this causes skin pigmentation due to production of POMC
renin and aldosterone levels in adrenal insufficiency
increased renin and decreased aldosterone
management of adrenal insufficiency
treatment must not be delayed to confirm diagnosis
replace steroids: 15-25mg hydrocortisone a day. give steroids in 2-3 doses to try to mimic diurinal rhythm
replace aldosterone: fludrocortisone - corrects postural hypotension and Na/K balance. Monitor K and BP carefully
education
how should steroids be given in the initial management of adrenal insufficiency if the patient is unwell
intravenously first
what education must be given for the management of adrenal insufficiency
There must be warning about abruptly stopping steroid use, and emphasis that prescribing doctors/surgeons/nurses etc. must know about steroid prescription.
A steroid treatment card must be carried at all times
what causes secondary Adrenocortical Insufficiency
lack of CRH/ACTH
- pituitary/hypothalamic disease
- tumours
- surgery/radiotherapy
- exogenous steroid use
what is the most common cause of secondaryAdrenocortical Insufficiency
exogenous steroid use
how do the clinical features of secondary Adrenocortical Insufficiency differ to those of Addison’s
skin is pale - no increased ACTH
aldosterone production is usually intact (as this is mainly under RAAS control not the HPA)
treatment of secondary Adrenocortical Insufficiency
hydrocortisone replacement
fludrocortisone not required
steroid dosing in illness
- double hydrocortisone dose in febrile illness, injury or stress
- fludrocortisone dose does not need to be increased
