Cardiovascular - Hypertension Midterm Notes PDF

3 1 CARDIOVASCULAR - Hypertension Hypertension Hypertension is a chronic medical condi3on where the blood pressure (BP) in the arteries is persistently elevated. It is classified into Primary (Essen9al) Hyper...

3 1 CARDIOVASCULAR - Hypertension Hypertension Hypertension is a chronic medical condi3on where the blood pressure (BP) in the arteries is persistently elevated. It is classified into Primary (Essen9al) Hypertension and Secondary Hypertension. 1. Most Likely Cause Primary Hypertension (accounts for 90-95% of cases): o No specific iden9fiable cause is established for primary hypertension o It results from a complex interac9on of gene9c and environmental factors that affect cardiac output and total peripheral resistance (TPR). o Contribu3ng factors for primary hypertension include: § Disturbance of auto-regula9on of blood flow. § Excess sodium intake and subsequent renal sodium reten9on. § Dysregula9on of the Renin-Angiotensin-Aldosterone System (RAAS) § Increased sympathe9c nervous system (SNS) drive【97:0†source】. § Endothelial dysfunc9on (impaired release of nitric oxide). § Insulin resistance and inflamma9on. Secondary Hypertension (5-10% of cases): o Caused by an iden3fiable underlying systemic disease or condi9on that increases vascular resistance or cardiac output. o Examples of causes of secondary hypertension: § Renal disease (renal artery stenosis, renal failure). § Endocrine disorders (e.g., pheochromocytoma, Cushing's syndrome). § Arteriosclerosis (hardening of the arteries). § Certain medica9ons (e.g., oral contracep3ves) and obstruc9ve sleep apnea. 2. Pathophysiology Primary Hypertension: o Sympathe9c Nervous System (SNS) Ac9va9on: § Overac3va3on of the SNS leads to vasoconstric9on, increased heart rate, and increased cardiac contrac9lity, all of which raise cardiac output and blood pressure. o Renin-Angiotensin-Aldosterone System (RAAS) Dysfunc9on: § Dysregula3on of the RAAS increases angiotensin II produc3on, leading to vasoconstric9on. § Aldosterone causes renal sodium and water reten9on, increasing blood volume and cardiac output. o Endothelial Dysfunc9on: § Reduced nitric oxide (NO) produc9on impairs vasodila3on, leading to increased peripheral resistance. o Increased Peripheral Vascular Resistance:  2 § The arteries and arterioles experience vascular remodeling, with increased smooth muscle cell prolifera3on and fibrosis of the in3ma layer. Secondary Hypertension: o Renal Dysfunc9on: § When kidneys fail to regulate blood volume and electrolytes, blood pressure increases due to fluid overload. o Endocrine Dysfunc9on: § Excess produc3on of aldosterone (as in primary aldosteronism) causes sodium and water reten3on, increasing blood volume. o Arteriosclerosis: § Hardening of blood vessel walls reduces their ability to dilate, leading to increased peripheral resistance. o Drug-Induced Hypertension: § Medica3ons like oral contracep9ves increase blood pressure through mechanisms involving RAAS and fluid reten3on. 3. Disease Transmission Transmission: o Hypertension is not a transmissible disease. o It results from a combina3on of gene9c predisposi9on and environmental factors. o Family history is a known risk factor, but it is not an infec3ous disease. 4. Risk Factors The risk factors for hypertension are classified into modifiable and non-modifiable factors. Modifiable Risk Factors Lifestyle and Dietary Factors: o Excess sodium intake (high-salt diets increase blood pressure). o Low potassium, calcium, or magnesium intake (these electrolytes play a role in vasodila3on). o Alcohol consump9on (more than 2 drinks per day). o Smoking (nico3ne causes vasoconstric3on and increases sympathe3c drive). o Physical inac9vity (sedentary lifestyle increases the risk of hypertension). o Obesity (especially central/abdominal obesity). o Stress (chronic stress ac3vates the sympathe3c nervous system). Metabolic and Endocrine Factors: o Glucose intolerance and insulin resistance (common in individuals with metabolic syndrome). o Hyperlipidemia (high levels of LDL cholesterol) indirectly increase blood pressure by contribu3ng to atherosclerosis. Non-Modifiable Risk Factors Age: o Hypertension becomes more prevalent with age due to arterial s3ffening and loss of vascular compliance.  3 Gender: o Men are at higher risk before age 55, but postmenopausal women have a higher risk a\er age 70 due to loss of estrogen's protec3ve effects. Race/Ethnicity: o African Americans are at higher risk of developing hypertension, poten3ally due to increased sensi3vity to dietary salt. Family History: o A family history of hypertension increases the risk of developing the disease due to gene3c predisposi3on. Summary Table Criteria Primary Hypertension Secondary Hypertension No single cause (90-95% of cases). Caused by renal, endocrine, and Cause Involves gene3cs, diet, and lifestyle. cardiovascular diseases. SNS overac3va3on, RAAS dysfunc3on, Disease-specific mechanisms like renal Pathophysiology endothelial dysfunc3on, increased failure or adrenal tumor peripheral resistance. (pheochromocytoma). Not transmissible (inherited Not transmissible (disease- Transmission suscep3bility). dependent). Modifiable: High sodium, low Risk factors relate to underlying potassium, obesity, stress, alcohol, Risk Factors systemic diseases (renal disease, smoking. Non-modifiable: Age, sex, pheochromocytoma, etc.). gene3cs, race.