Flashcards in Diagnosis of Adrenal Disorders Deck (38)
What is the structure that is common to all steroids?
What is cortisol also know as?
What is cortisone?
Very weak glucocorticoid
Biologically inactive metabolite of cortisol
What happens to cortisone after administration to a patient?
Metabolised to cortisol in liver
What is the major glucocorticoid?
What is the action of glucocorticoids?
Stimulation of gluconeogenesis in liver
Mobilisation of amino acids in muscle
Stimulation of lipolysis in adipose tissues
What does too much cortisol lead to?
Salt retention > hypertension
Inhibition of linear growth
What can cause ACTH-dependent hypercortisolism?
Pituitary adenoma = Cushing's disease
Ectopic ACTH syndrome
What can cause ACTH-independent hypercortisolism = Cushing's syndrome?
ACTH-independent nodular hyperplasia
Administration of glucocorticoids
What is the most common cause of Cushing's syndrome?
Administration of glucocorticoids
What happens in abnormal states when you deliberately stimulate/suppress the hormone to test for its function?
Hormone won't rise into normal range when you stimulate it
Won't fall into normal range if you suppress it
What is a 24 hour urine assay useful for?
Tell you about variation throughout day
How do you investigate suspected Cushing's syndrome?
24 hour urine free cortisol
Check diurnal variation: serum cortisol and plasma ACTH
- 8 am
- 12 am
Check negative feedback loop working: dexamethasone suppression test
Cranial MRI/adrenal CT as indicated
What is dexamethasone?
Very powerful glucocorticoid
What happens when someone is given dexamethasone?
Should decreased ACTH and cortisol
What does it mean if ACTH and cortisol don't decrease when dexamethasone is given?
Something wrong with pituitary
What does not enough cortisol cause?
Can't cope with new stress; eg: infection
- Much sicker than they should be
- Weight loss
Salt wasting > low BP
Darkening of skin if ACTH secretion stimulated
What are the possible causes of adrenocortical insufficiency?
- Enzyme defect in cortisol biosynthesis
- Metabolic defect = adrenoleukodystrophy
Autoimmne adrenal destruction
- Adrenal destruction by TB
What is the most common cause of Addison's disease in Australia?
Autoimmune destruction of adrenal cortex
What are the clinical findings for Addison's disease?
Salt-wasting state > low Na and high K
How do you treat Addison's disease?
Where does Addisonian pigmentation commonly occur?
Knuckles of hands
Gums and oral mucosa
What happens when there is an excess of adrenal androgens?
Premature pubic hair
Enlargement of penis/clitoris in child
Linear growth spurt
Rapid epiphyseal fusion in child
Deepening of voice
What is the cause of congenital adrenal hyperplasia (CAH) in 90% of cases?
What is the inheritance pattern of CAH?
What is the pathophysiology of CAH?
Variable impairment of cortisol and aldosterone synthesis > ACTH stimulation > adrenal hyperplasia > increased androgen > virilisation
What are the three different presentations of CAH in females?
Exposed to high levels of androgens in utero > infant with ambiguous genitalia
In utero androgens not that high > happens more slowly > premature pubic hair and enlarged clitoris
Adolescent hirsutism and acne
What are the presentations of CAH in males?
Adrenal crisis in baby aged 2-3 weeks
Premature sexual development at age 2-3 years
Why is there a decrease in oestrogen in CAH?
Made from testosterone and aromatase very tightly regulated
Do have slightly elevated levels