Hypertension Flashcards
How do you calculate blood pressure and cardiac output?
BP = cardiac output x total peripheral resistance CO = stroke volume x heart rate
What are the current joint national committee levels for hypertension?
Normal: 120/80
Pre HTN: 120/80 - 139/89
HTN 1: 140/90 - 160/100
HTN 2: >160/100
What has control over blood pressure regardless of how high cardiac output and total peripheral resistance are?
Renal Excretion
How does the carotid sinus regulate blood pressure?
- High blood pressure stretches the carotid sinus.
- The stretch in the vessel wall sends a signal up CN IX to the nucleus tractus solitaries in the brainstem medulla
- sympathetic stimulation is inhibited and parasympathetic stimulation occurs
How does the aortic arch regulate blood pressure?
- High blood pressure stretches the carotid sinus.
- The stretch in the vessel wall sends a signal up CN X to the nucleus tractus solitaries in the brainstem medulla
- sympathetic stimulation is inhibited and parasympathetic stimulation occurs
How is essential hypertension diagnosed?
It is diagnosed by exclusion. When all other etiologies are ruled out you are left with primary or essential hypertension.
What are the 4 theoretical mechanisms explaining how hyperinsulinemia may cause essential HTN?
- Stimulates Renal absorption increasing volume
- Increases SANS activity increasing circulating catecholamines
- Mitogen that stimulates vascular smooth muscle hypertrophy
- Alters membrane transport increasing intracellular calcium and vascular tone
-a mitogen is a chemical substance (like insulin) that encourages mitosis
What is the theory behind leptin contributing to essential hypertension?
Leptin activates the SANS
What is the difference in the proposed cause of essential hypertension in younger patients vs. older patients? What would the treatments then be?
Younger: due to elevated CO
-Tx: beta blockers
Older: due to elevated TPR
-Tx: vasodilators
Top two most common causes of Renovascular HTN (a type of secondary HTN) and treatments for each.
Men: atherosclerosis
-Tx: stent
Women: fibromuscular dysplasia
-Tx: angioplastic balloon
Treatment for a unilateral Renal artery stenosis leading to Renovascular HTN.
ACE-Is
What is the mechanism that leads to secondary HTN in a patient with aortic coarctation?
- Coarctation causes low renal blood flow (RBF)
- Kidneys respond to low RBF with Renin-Ag-Ald system
- Atherosclerosis also occurs proximal to the stenosis and baroceptor’s neural regulation is less sensitive
Radiography clue to aortic coarctation and treatment.
Dx: notched ribs on chest X-ray
Tx: angioplasty
Tx. for pheochromocytoma.
Phenoxybenzamine
Etiology and diagnosis of primary vs. secondary aldosteronism.
Primary
Cause: aldosterone-secreting adenoma in adrenal glands
Dx: high aldosterone levels and low renin levels
Secondary
Cause: renin-secreting tumor
Dx: high renin levels, high Ag II levels, low aldosterone levels