Primary and Secondary Hypertension

Question 1

How many cases of HTN are primary? Secondary?

Answer 1

• primary: 85 - 90%

- secondary: 10 - 15%

Question 2

What are the two leading causes of Secondary HTN?

Answer 2

• renal disease and primary aldosteronism

Question 3

Primary Aldosteronism is also known as:

Answer 3

• Conn’s syndrome

Question 4

How can we tell the difference between Secondary HTN due to Renal Disease vs. due to Primary Aldosteronism?

Answer 4

• in renal disease, there will be high aldosterone AND high renin (the renin will cause the aldosterone)
• in primary aldosteronism, there will only be high aldosterone

Question 5

Other than Renal Disease and Primary Aldosteronism, what are three other causes of Secondary HTN?

Answer 5

• phaeochromocytoma, Cushing’s disease, congenital adrenal hyperplasia

Question 6

Phaeochromocytoma

Answer 6

• tumor(s) in the adrenal gland, resulting in an increase in adrenaline or noradrenaline
• can lead to paroxysmal/episodic bursts of secondary HTN

Question 7

Cushing’s Disease

Answer 7

• gluco-corticoid excess usually due to an issue with the hypothalamic-pituitary-adrenal axis
• the excess cortisol can lead to secondary HTN

Question 8

Pathophysiology of Cushing’s Disease in the context of a broken hypothalamic-pituitary-adrenal axis.

Answer 8

• hypothalamus secretes CRH, causing the pituitary gland to secrete ACTH, which triggers the adrenal cortex to release cortisol (excess cortisol –> high BP)

Question 9

What can cause Cushing’s Disease?

Answer 9

• prolonged use of corticosteroids (iatrogenic), ACTH hypersecretion from a pituitary adenoma, ectopic ACTH secretion, cortisol hypersecretion from adrenal issue

Question 10

Congenital Adrenal Hyperplasia

Answer 10

• 95% of cases are due to a 21-hydroxylase deficiency (secondary HTN does NOT occur in these patients)
• 5% are due to an 11-hydroxylase deficiency (secondary HT DOES occur here)

Question 11

In Primary Aldosterone, what type of cells would you see on histology of the malignant adrenal gland?

Answer 11

• tons of glomerulosa type cells (these cells are responsible for aldosterone secretion)

Question 12

ACTH

Answer 12

• adrenocorticotropic hormone
• secreted by the pituitary gland in response to the hypothalamus’ CRH
• acts on the adrenal cortex to stimulate release of cortisol

Question 13

CRH

Answer 13

• corticotropin releasing hormone
• secreted by the hypothalamus in response to stress and low blood glucose
• acts on the pituitary gland to stimulate the release of ACTH

Question 14

Cortisol

Answer 14

• secreted by the zona fasiculata in the adrenal cortex
• increases blood glucose via gluconeogenesis, suppresses immune system, and increases metabolism of fat, protein, and carbohydrates