11.4: Htn Flashcards Preview

MHD V: Renal > 11.4: Htn > Flashcards

Flashcards in 11.4: Htn Deck (38):
1

What is blood pressure a product of?

1. Cardiac output
2. Systemic vascular resistance

2

MAP equation

MAP = DBP + (SBP - DBP) / 3

3

What impacts stroke volume related to kidney?

Na balance

4

How does kidney in pact peripheral resistance?

RAS leads to vasoconstriction

5

Is hypertension usually result of increase CO or PVR?

Usually increased PVR

6

What are EDRF and endothelin?

Endothelium: causes constriction
EDRF: Causes dilation

7

What does increased adrenergic tone lead to?

Hypertension
1. Increases vasc tone
2. Increases NA Retention
3. Increases inotropy
- Blockade of sympathetics reduces BP

8

Effects of angiotensin II?

1. Vasoconstriction
2. Na resorption in prox tubule
3. Increases aldosterone: increases Na reabsorption in ducts

9

Effect of salt on Htn.?

- Increases BP
- There is a subset of hypertensives who show exaggerated increase
- It is recommended everyone should restrain Na although it does not impact everyone

10

What is the guyton hypothesis?

"Pressure natriuresis"
- Kidneys regulate arterial pressure by altering renal Na and water excretion
- Pressure goes up, excretion goes up
- In Htn., pressure natriuresis is maintained at higher BPs

11

What is monogenic Htn. usually result of?

- Na retention
- Most hypertension is polygenic

12

Role of kidneys in development of Htn.?

- Pressure natriuresis is abnormal in all types of Htn.
- No particular renal defect has been determined however

13

Main causes for secondary Htn.?

1. Kidney disease
2. Renal artery stenosis
3. Hyperaldosteronism
4. Pheochromocytoma

14

Volume mediated causes of secondary hypertension?

Non renal:
1. Hyperaldosteronism
2. Cushings
3. Mineralocorticoid tumors
Renal:
1. Renal failure
2. Acute glomerulonephritis

15

Vasoconstrictor mediated causes of secondary Htn.?

1. Pheochromocytoma
2. Unilateral renal artery stenosis
3. Hypercalcemia

16

What is pheochromocytoma?

- Tumor of Adrenal medulla
- Enormous Ne productions
- Leads to massive vasconstriction

17

How is pheochromocytoma treated?

- Surgery is standard of care
- Phenoxybenzamine or Phentolamine used before surgery
- These are Adrenergic blockers

18

What does hypercalcemia cause?

1. Enters smooth muscle cells and causes vasoconstriction

19

Clinical presentation of renal artery stenosis?

1. Severe and Difficult to control Htn.
2. Kidney failure
3. Flash pulmonary edema

20

Disease processes of renal stenosis?

1. Atherosclerotic 95%
2. Fibromuscular dysplasia

21

Physiology when one kidney is stenosed?

- Ischemic kidney releases renin
- Healthy kidney has suppressed renin but demonstrates pressure natriuresis
- Htn develops because ischemic kidney cant turn off RAS
***Treat by blocking RAS system of fix kidney

22

How is treatment of stenosis different if ptn. only has solitary kidney?

- RAS inhibitors can be used
- However, must also couple with diuretic as don't have healthy kidney to decrease volume

23

Problem in bilateral renal stenosis?

- Both kidneys have increased RAS
- Neither can diurese so volume is problem

24

Effect of excess aldosterone?

- Increased Na and H2O retention leading to Htn.

25

What is hyperaldosteronism usually a result of?

- Adrenal hyperplasia
- Tumor is rare
- Diagnosed by high ADH w/ low Angiotensin
- Ratio > 35% means primary aldosteronism

26

How does kidney disease lead to Htn?

- Decrease GFR leads to decrease Na/H20 excretion
- Leads to excess volume worsening Htn.
- In advanced kidney disease, Htn is volume related

27

What leads to fibrinoid necrosis?

Malignant Htn.

28

Kidney size change in essential and malignant Htn.?

Essential: Kidney size shrinks, hyaline arteriosclerosis
Malignant: Fibrinoid necrosis seen, normal kidney size

29

What are the characteristics malignant retinopathy?

1. Flame shaped hemorrhages
2. Cotton wool exudates
3. Papilledema

30

How do kidneys protect self in systemic htn.?

- Vasoconstriction of afferent arteriole

31

What is autoregulatory range of kidney?

- 60 -160 mmHg
- Beyond this GFR increase dramatically

32

2 Mechanisms of autoregulation of GFR?

1. Myogenic response
2. Tubuloglomerular feedback

33

What is the myogenic response?

- Reflex vasoconstriction of afferent in response to increase pressure by smooth muscle contraction
- Can also be dilation
***Main mechanism of autoregulation

34

What impairs autoregulation of kidneys?

- Dihydropyridine Ca antagonists
- Prevent normalization of glomerular pressure
- Prevent Ca from entering which normally would allow for constriction

35

Impact of dihydropyridine Ca antagonists?

Disables ability of kidneys to autoregulate

36

Contraindications of dihydropyridine Ca antagonists?

1. Renal disease
2. Proteinuria

37

Impact of diabetes on autoregulation?

Impairs it

38

In which form of renal stenosis is htn volume related? RAS?

RAS: unilateral, treat with blockers
Volume: Bilateral, one kidney,