1b Adrenal Disorders Flashcards
What hormones are produced in the adrenal cortex?
Corticosteroids
What are the corticosteroids?
Mineralcorticosteroids
Glucocorticoids
Sex Steroids
What is the precursor for steroid hormones?
Cholesterol
What is the effect of angiotensin II on the adrenals?
Activation of the following enzymes
Side Chain Cleavage
3 Hydroxysteroid dehydrogenase
21 hydroxylase
11 hydroxylase
18 hydroxylase
What is the action of aldosterone?
Increases blood pressure, retains sodium and lowers potassium
What is the effect on ACTH on the adrenals:
Activation of the following enzymes
Side Chain Cleavage
3 Hydroxysteroid dehydrogenase
21 hydroxylase
11 hydroxylase
17 hydroxylase
Describe the rhythm of cortisol release?
Diurnal secretion
What is primary adrenal failure?
Autoimmune disease where the immune system destroys the adrenal cortex, therefore insufficient steroid hormone production
What are the symptoms of an adrenal crisis?
Fever
Syncope
Convulsions
Hypoglycaemia
Vomiting
Diarrhea
What are the symptoms of an adrenal crisis?
Fever
Syncope
Convulsions
Hypoglycaemia
Vomiting
Diarrhea
Why do patients with Addison’s have a good tan?
POMC is a large precursor
protein that is cleaved to form
a number of smaller peptides,
including ACTH, MSH and
endorphins
Thus people who have
pathologically high levels of
ACTH may become tanned
Describe the changes to the skin in patients with Addisons?
Autoimmune Vitiligo
Hyperpigmentation
Good Tan
What are the three causes of adrenocortical failure?
TB - tuberculous Addisons Disease
Autoimmune destruction - Autoimmune Addison’s disease
Born without the necessary enzymes
What is POMC?
Pro-opio melanocortin
Where is POMC made
Pituitary
What is POMC broken down into?
ACTH, MSH, Endorphins and enkephalins
What are the consequences of Adrenocortical Failure?
Fall in blood pressure
*Loss of salt in the urine
*Increased plasma potassium
*Fall in glucose due to glucocorticoid
deficiency
*High ACTH resulting in increased
pigmentation
Describe the visual symptoms of Addison’s?
Hyperpigmentation
Vitiligo
Mucous Membrane hyperpigmentation - therefore definately not sun tan as these areas are not accessible
Darkening of hair
Muscles weakness
What is the test for Addison’s?
SynACTHen test
How does the SynACTHen test work?
Measure cortisol at 9am
Administer injection of SynACTHen and remeasure cortisol levels
What test results of ACTH suggest Addisons?
Low Cortisol following synACTHen administration
Why can aldosterone not be given to patients with Addison’s?
Aldosterone has too short a half life, therefore would have to be given multiple times a day in order to be effective
What is give to patients with Addisons?
Fludrocortisone - does not exist in natural steroids, therefore presence slows metabolism
Prednisolone - longer half life and more potent than cortisol, rapidly absorbed with half life suitable for once daily administration
What is the dose for prednisolone daily?
3.75mg daily
What is the dosage of fludrocortisone?
50 to 100 mcg daily
Which hormones will be completely absent in complete 21-hydroxylase deficiency?
Aldosterone and Cortisol
How long can you survive without treatment with 21-hydroxylase deficiency?
less than 24 hours
Which hormones will be in excess in complete 21-hydroxylase deficiency?
Sex steroids like testosterone
What is the youngest age of presentation with Adrenal Disorders?
As a neonate with a salt losing Addisonian Crisis