Adrenal Diseases Flashcards
What are the two parts of the adrenal gland?
- cortex
- medulla
What does the cortex secrete?
glucocorticoids, mineralocorticoids and androgens
What does the medulla secrete?
catecholamine
Describe the main mineralcorticoid?
Aldosterone
Involved in the renin-angiotensin system and ADH in the maintenance of blood volume
Causes of adrenocortical hyperfunction?
Hyperplasia (includes cushings, pituitary disease, congenital issues), adenoma and carcinoma
Causes of primary adrenocortical hypofunction?
Chronic: Addison’s disease
Acute: Water-Friderichsen syndrome (bleeding in glands due to severe bacterial infection)
Describe location of the adrenal glands?
Bilateral and sit superior and medial to the upper pole of the kidneys
Weight of normal adrenal glands?
4-5g (so can be quite hard to find)
Describe pathology of adrencortical adenomas?
Well circumscribed, encapsulated yellow brown lesions, cells resemble adrenal cortical cells, well differentiated, more often non-functional so can be an incidental finding
Describe pathology of adrenocortical carcinomas?
Rare, more likely to be functional, can closely resemble adenoma. Can be difficult to distinguish between benign and malignant, and sometimes only definite is if it has metastasised. Other features: large size, haemorrhage, necrosis, frequent mitoses, atypical mitoses, lack of clear cells, capsular or vascular invasion (added together)
Cushing’s syndrome vs Conn syndrome?
Cushings= corticosteroid excess Conn= mineralocorticoid excess
What is Addison’s disease?
Chronic Adrenal Insufficiency
3 causes of addison’s disease?
Auto-immune adrenalitis- most common
Tuberculous destruction of adrenals
Metastatic neoplasms
What cells in the medulla secrete catecholamines?
Chromaffin cells
What are three adrenal medullary tumours?
Phaeochromocytoma
Ganglioneuroma
Neuroblastoma
What type of cells are phaeochromocytomas composed of? What do they therefore secrete?
Chromaffin cells
Catecholamines
What are neuroblastomas? Who do they arise in?
very malignant tumour of primitive nerve cells occurring in children
Describe phaeochromocytomas and if you know if they are malignant?
More of a spectrum. Difficult to tell if malignant from histology as like with most endocrine tumours it cells don’t predict how the tumour will act, only really know if it has metastasised. Malignant tumours tend to be larger.
Layers of cortex from outside to inside closest to medulla?
Zona glomerulosa
Zona fasciculata
Zona reticularis
Zona glomerulosa secretes ___1____
Zona fasciculata secretes ____2____
Zona reticularis secretes ____3___
1) aldosterones/ mineralocorticoids
2) cortisol/ glucocorticoid
3) Androgens
Cortisol and androgen secretion is controlled by which axis? What axis is aldosterone controlled by? Clinical implications?
Cortisol and androgens by hypothalamic pituitary. Mineralocorticoids by the RAAS system, so if pituitary disease it shouldn’t be affected.
Major actions of cortisol?
Changes mood- euphoria and psychosis
Accelerates osteoporosis, decreases serum calcium, decreases collagen formation and wound healing
Decreases capillary dilation and permeability, decreases leucocyte migration, decreases macrophage activity and inflammatory cytokine production
Increases blood sugar, increases fat deposition, central redistribution, increases proteolysis
Increases CO, BP, renal blood flow and GFR
Does RAAS system increase or decrease blood pressure? What system counteracts it?
Increase
Natriuretic Peptides
3 main components of the RAAS system?
Renin
Angiotensin
Aldosterone
Describe activation of the RAAS system
Stimulated by renal artery hypotension, renal sympathetic nerves or decreased sodium in renal tubular fluid
- Renin is released from the kidneys and stimulates the formation of angiotensin I in the blood from angiotensinogen (produced by the liver)
- Angiotensin I is converted to angiotensin II by Angiotensin converting enzyme - ACE (mainly produced by pulmonary vascular endothelium)
- Angiotensin II (1) stimulates the release of Aldosterone from the adrenal cortex (2) Causes systemic vasoconstriction - increases SVR. It also stimulates thirst and ADH release - i.e. contributes to increasing plasma volume mainly brought about by aldosterone
- Aldosterone (a steroid hormone) acts on the kidneys to increase sodium and water retention – increases plasma volume
Primary hypoadrenalism/ addisons causes?
Usually due to auto-immune destruction of adrenal gland- more than 90% destroyed before symptomatic
In developing countries may be TB related
Could be caused by metastatic neoplasms
(often Addisons just refers to auto-immune form)
Addisons is more common in male or females? What else is associated?
Females
Other autoimmune diseases and 21 hydroxylase antibodies
Most common antibody in addisons?
21 hydroxylase