15.10 Adrenal Cortex Flashcards
What is generated in the glomerulosa?
Mineralocorticoids - aldosterone
What is generated in the fasciculata?
Glucocorticoids - cortisol
What is generated in the reticular?
Sex Steroids
Cushing Syndrome
Excess cortisol
What are the features of Cushing syndrome?
- Moon facies
- Buffalo hump
- Truncal obesity
- Muscle weakness
- HTN
- Osteoporosis
- Immune suppression
How does cortisol cause HTN?
Upregulation of alpha-1 receptors
How does cortisol cause immunosuppression?
- Inhibition of IL-2
- Inhibition of phospholipase A2
- Inhibits histamine
What are the causes of Cushing syndrome?
- Exogenous corticosteroids
- Adrenal adenoma, hyperplasia or carcinoma
- ACTH-secreting pituitary adenoma
- Paraneoplastic ACTH secretion
What tumor can cause paraneoplastic ACTH secretion?
SCC of the lung
What cause of Cushing syndrome will cause bilateral adrenal atrophy?
Exogenous corticosteroids
What will respond with decreased ACTH in response to dextromethasone?
Pituitary adenoma - SCC of the lung will NOT
Hyperaldosteronism
Excess aldosterone
What are the features of hyperaldosteronism?
- Hypernatremia
- Hypokalemia
- Metabolic Alkalosis
- HTN
What is the most common cause of primary hyperaldosteronism?
Adrenal Adenoma
What are the lab findings for renin and aldosterone in primary hyperaldosteronism?
- High aldosterone
- Low renin
What are the causes of secondary hyperaldosteronism?
Activation of the RAA system leading to high aldosterone with high renin - often due to renovascular HTN
Congenital Adrenal Hyperplasia
Excess sex steroids with hyperplasia of both adrenal glands
What is the most common cause of congenital adrenal hyperplasia?
21-hydroxylase deficiency
Why is there hyperplasia in the adrenals in congenital adrenal hyperplasia?
There is a deficiency of cortisol as all steroid genesis is shunted towards sex steroids - leads to increased ACTH and adrenal hyperplasia
What is 21-hydroxylase required for?
Mineralcorticoid and cortisol production
What are the clinical features of congenital adrenal hyperplasia?
- Hyponatremia
- Hyperkalemia
- Hypovolemia
- Hypotension that is life threatening
What happens with 11-hydroxylase deficiency?
- No cortisol
- Only weak mineralocorticoid production so no salt wasting
- Most is shunted to sex steroid production
What is required for pregnenolone to enter into the synthesis pathway and become cortisol or sex steroids?
17-hydroxylase - if deficient there will be excess mineralocorticoids
Adrenal Insufficiency
Lack of adrenal hormones
Waterhouse-Friderichsen Syndrome
Often in a young child with N. meningitides who develops DIC with bilateral adrenal atrophy - “sack of blood”
Chronic Adrenal Insufficiency
Slow destruction of the adrenal glands
What are some of the causes of chronic adrenal insufficiency?
- Autoimmune (common in West)
- TB (common in 3rd world)
- Metastatic Carcinoma
What cancer often metastasizes to the adrenal glands?
Lung cancer
