Adrenal Disease Flashcards
Why do adrenal carcinomas have a poor prognosis?
Symptoms do not appear until nerves have become involved - this occurs late in disease progression pathway.
What features suggest an adrenal carcinoma, rather than an adenoma?
Large size
Presence of haemorrhage/necrosis
Frequent and atypical mitoses
A lack of clear cytoplasm
Capsular/vascular invasion
How is adrenal function affected in long-term steroid therapy?
It will be reduced (as ACTH release is suppressed by these steroids).
What are causes of acute adrenocortical insufficiency?
Rapid removal of long-term steroids
Haemorrhage
Disseminated intravascular coagulation
Sepsis
What is the most common cause of chronic adrenocortical insufficiency?
Addison’s disease
What is a neuroblastoma?
A cancer usually diagnosed in the first 18 months of life.
Around 40% of these affect the adrenal medulla, however can develop anywhere along the sympathetic chain.
What are phaeochromocytomas?
Tumours derived from chromaffin cells in the adrenal medulla.
What is secreted by phaechromocytomas?
Catecholamines, causing hypertension.
How does aldosterone raise BP?
It increases the rate of salt and water resorption, increasing the volume of blood.
How do steroids work?
They act on nuclear receptors, interacting with DNA directly. Produces a change in the way genes are expressed.
What is the role of mineralocorticoids?
Regulate the body’s sodium/potassium balance, blood pressure regulation and the maintenance of extracellular volume.
What are primary causes of adrenal insufficiency?
Addison’s disease (most common)
Congenital adrenal hyperplasia
Adrenal infection
Malignancy
What are secondary causes of adrenal insufficiency?
A lack of ACTH production
Iatrogenic (due to excess exogenous steroids which inhibit CRH and ACTH)
Pituitary/hypothalamic disorders
What is Sheehan’s syndrome?
A potentially life-threatening condition in which, following labour, a mother loses a significant amount of blood, producing damage to the pituitary gland.
What is Addison’s disease?
Autoimmune destruction of the adrenal cortex.
Symptoms present when >90% of the gland has been destroyed.
How does Addison’s disease present within electrolyte sample?
High potassium
Low sodium
How does Addison’s disease show on a synacthen test?
ACTH will be very high, renin will be raised and aldosterone will be low.
How is adrenal insufficiency treated?
Give hydrocortisone to replace cortisol, and fludrocortisone to mimic aldosterone.
During this, ensure to monitor BP and potassium levels.
How should adrenal-insufficient patients adjust their steroid dose when unwell?
Increase dose
At no point should steroid replacement ever be stopped.
How can primary and secondary adrenal insufficiency be differentiated?
Secondary adrenal insufficiency will not cause hyperpigmentation (as there is no excess ACTH).
Why is hydrocortisone replacement NOT given in some patients?
No hyperpigmentation signals that there is no shortage of aldosterone as an excess of ACTH is not present, hence hydrocortisone therapy is not indicated.
What are common features of Cushing’s syndrome?
Easy bruising
Facial plethora
Skin striae
Proximal myopathy
Central obesity
What is Cushing’s often dependent on?
ACTH (as this is needed to produce cortisol).
What tests can be used to diagnose Cushing’s syndrome?
Overnight dexamethasone suppression test
24hr urinary free cortisol
Low dose dexamethasone suppression test (GOLD standard)
