Hypertension Overview and Pathophysiology

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What percentage of hypertension cases are classified as essential hypertension?

92-94% (correct)

4-5%

1-2%

6-8%

Which of the following is NOT a cause of secondary hypertension related to renal disorders?

Diabetic nephropathy

Pheochromocytoma (correct)

Renal artery stenosis

Chronic pyelonephritis

Which condition is classified as an adrenal dependent cause of hypertension?

Diabetic nephropathy

Hypothyroidism

Cushing syndrome (correct)

Hyperparathyroidism

What is one potential emergency situation related to adrenal dependent causes of hypertension?

Pheochromocytoma crisis Signup and view all the answers

Which of the following is a thyroid dependent cause of hypertension?

Hyperthyroidism Signup and view all the answers

What is the effect of angiotensin-converting enzyme (ACE) inhibitors on blood pressure values necessary for effective natriuresis?

They shift the curve to the left, reducing blood pressure values. Signup and view all the answers

Which of the following mechanisms primarily controls peripheral vascular resistance?

Small arteries and arterioles. Signup and view all the answers

What contributes to microvascular remodeling and arteriolar damage leading to hypertension?

Renal vasoconstriction and subsequent renal ischaemia. Signup and view all the answers

In cases of primary aldosteronism, what is generally observed in the levels of renin?

Decreased renin due to increased aldosterone. Signup and view all the answers

What are early indicators of hypertension and target-organ damage?

Endothelial dysfunction and vascular remodelling. Signup and view all the answers

What percentage of patients with hypertension is estimated to have secondary hypertension with an identifiable cause?

10% Signup and view all the answers

Which of the following risk factors is NOT mentioned as being associated with hypertension?

High physical activity Signup and view all the answers

What is a key renal mechanism for blood pressure (BP) control?

Pressure–natriuresis relationship Signup and view all the answers

Chronic activation of the RAAS has what effect on the pressure–natriuresis curve?

Shifts it to the right Signup and view all the answers

Which of these conditions is associated with an increased risk due to hypertension?

Atrial fibrillation Signup and view all the answers

What type of hypertension accounts for the majority of cases?

Essential (primary) hypertension Signup and view all the answers

What role do the kidneys play in the regulation of blood pressure?

Regulate sodium excretion and volume status Signup and view all the answers

What is one consequence of hypertension if left uncontrolled?

Hypertension-mediated organ damage (HMOD) Signup and view all the answers

Which condition is characterized by gradual onset and often associated with obesity?

Essential Hypertension Signup and view all the answers

What is a characteristic feature of secondary hypertension?

Onset at age extremes Signup and view all the answers

Which of the following conditions is classified as irreversible?

Chronic Renal Failure Signup and view all the answers

Which of these conditions is associated with hypertensive mediated organ damage?

Hypertensive heart disease Signup and view all the answers

What symptom is least likely to be associated with secondary hypertension?

Slowly progressive increase in BP Signup and view all the answers

Which mechanism is a common iatrogenic cause of hypertension?

NSAID use Signup and view all the answers

What is a characteristic feature of essential hypertension?

Lack of laboratory evidence of secondary causes Signup and view all the answers

Which of the following is considered a reversible cause of hypertension?

Acute renal disease Signup and view all the answers

What is considered an indication of postural hypotension?

A decrease of ≥20 mmHg in systolic BP when measured standing Signup and view all the answers

Which condition is more frequently observed in women with respect to hypertension?

Left atrial dilatation Signup and view all the answers

How is diastolic blood pressure most accurately measured using Korotkoff sounds?

At the complete disappearance of the fifth Korotkoff sound Signup and view all the answers

What is a characteristic of automated office blood pressure measurement?

Can be conducted unattended to minimize the white coat effect Signup and view all the answers

What is the significance of an inter-arm difference in blood pressure measurements?

Suggests potential vascular issues if >10 mmHg Signup and view all the answers

What is the definition of white-coat hypertension?

Normal BP readings in clinical settings but elevated in home monitoring Signup and view all the answers

Which of the following best describes systolic blood pressure?

Maximum arterial pulsatile pressure during heart contraction Signup and view all the answers

Which of the following is correct regarding the measurement of diastolic blood pressure under specific conditions?

May be inferred from the fourth Korotkoff sound if the fifth is absent Signup and view all the answers

Study Notes

Hypertension

Associated with 3-4 times increased risk of:
- Coronary artery disease
- Acute coronary syndrome
- Heart failure (mostly HF with preserved LVEF)
- Atrial fibrillation
- Stroke
- Peripheral artery disease
- Renal failure

Pathophysiology of Hypertension

The majority of patients have essential hypertension (cause unknown)
Estimated 10% have secondary hypertension with an identifiable cause (e.g. renal or endocrine problems)
Complex interactions between environmental, behavioral factors, genes, hormones, and multiple organ systems (renal, cardiovascular, and central nervous system) are involved
Vascular and immune mechanisms also play a role
Dysregulation of these processes leads to the development of hypertension, which can lead to hypertensive-mediated organ damage (HMOD)

Renal Mechanisms in Hypertension

Kidneys are key regulators of blood pressure and impaired renal function leads to hypertension.
Two significant mechanisms are the pressure-natriuresis relationship and the Renin-Angiotensin-Aldosterone System (RAAS).
Pressure-natriuresis reflects the kidney's ability to balance sodium excretion with dietary intake to maintain normal blood pressure.
In healthy individuals, the RAAS is activated by low sodium intake, stimulating renal sodium reabsorption, preserving intravascular volume and blood pressure.
High sodium intake leads to suppression of the RAAS to facilitate sodium excretion.
Chronic RAAS activation shifts the curve to the right, requiring higher blood pressure values to excrete similar sodium loads.
ACE inhibitors or ARBs shift the curve to the left, reducing blood pressure.
Impaired tubular ion transport leads to salt-sensitive hypertension with volume retention.
Renal vasoconstriction can lead to renal ischemia, stimulating inflammation, increasing reactive oxygen species, contributing to microvascular remodeling, damage, and hypertension.

The Renin-Angiotensin-Aldosterone System (RAAS)

Plays a crucial role in regulating blood pressure.
Excessive activation of the RAAS can lead to hypertension
Primary causes of RAAS activation:
- Primary adrenal adenomas, hyperplasia
- Increased aldosterone, decreased renin
Secondary causes of RAAS activation:
- Congestive heart failure
- Renal disease
- Pregnancy Increased renin and aldosterone levels

Autonomic Nervous System Activities

Plays a crucial role in regulating blood pressure
Sympathetic nervous system stimulation increases heart rate and blood pressure
Parasympathetic nervous system stimulation decreases heart rate and blood pressure

Vascular Mechanisms in Hypertension

Structural and functional changes in small and large arteries play a role in the pathophysiology of hypertension.
Peripheral vascular resistance is controlled mainly at the level of small arteries and arterioles.
Endothelial dysfunction and vascular remodeling are early signs of hypertension and target-organ damage.
These vascular alterations both initiate and maintain hypertension, therefore, are both a cause and consequence of high blood pressure.

Causes of Hypertension

Essential hypertension: 92-94% of cases
Secondary hypertension: 6-8% of cases
- Renal: 4-5%
- Miscellaneous: ~2%
- Endocrine: 1-2%

Secondary Hypertension due to Renal Disorders

Chronic pyelonephritis
Acute and chronic glomerulonephritis
Polycystic kidney disease
Renal artery stenosis
Arterial nephrosclerosis
Diabetic nephropathy
Renin-secreting tumors

Endocrine Causes of Hypertension

Adrenal Dependent Causes

Pheochromocytoma
Primary aldosteronism
Hyperdeoxycorticosteronism:
- Congenital adrenal hyperplasia (11β hydroxylase/17α hydroxylase deficiency)
- Deoxycorticosterone-producing tumor
- Primary cortisol resistance
Cushing syndrome

AME/11β-HSD Deficiency

Genetic:
- Type I AME
Acquired:
- Licorice or carbenoxolone ingestion (Type I AME)
- Cushing syndrome (Type II AME)

Thyroid Dependent Causes

Hypothyroidism
Hyperthyroidism

Parathyroid Dependent Causes

Hyperparathyroidism

Pituitary Dependent Causes

Acromegaly
Cushing disease

Reversible and Irreversible Causes of Secondary Hypertension

Reversible Causes

Renal:
- Renal Artery Stenosis
- Chronic renal failure due to pyelonephritis
- Acute renal disease
- Renal parenchymal disease
- Hydronephrosis
- Renin-producing tumors
Endocrine
Vascular:
- Aortic Coarctation
- Vasculitis:
  - Polyarteritis Nodosa (PAN)
  - Scleroderma
  - Takayasu Arteritis
Iatrogenic Toxic:
- Glucocorticoids, NSAIDs, decongestants, liquorice, alcohol

Irreversible Causes

Renal:
- Chronic renal failure
- Polycystic kidney disease
- Monogenic syndromes:
  - Gitelman
  - Liddle
  - Barter syndrome

Essential Hypertension

Onset in 30s and 40s
Gradual onset
Gradual progression of hypertension, requiring the addition of medications over time
Lack of severe end-organ damage
Family history
Often associated with obesity
Lack of signs and symptoms of secondary causes
Lack of laboratory evidence of secondary causes

Secondary Hypertension

Hypertension onset at age extremes (over 50)
Lack of family history
Refractory (resistant) hypertension
Rapid onset of severe hypertension
More severe hypertension-mediated organ damage (e.g. Grade III/IV retinopathy, left ventricular hypertrophy, CHF, CKD)
Signs and symptoms of secondary etiologies
Laboratory evidence of secondary etiologies

Clinical Consequences of Hypertension

Longstanding hypertension causes organ damage, leading to cardiovascular, cerebrovascular, and renal disease.
Evidence of HMOD typically indicates long-standing elevated blood pressure or hypertension, and confers increased risk with regards to CVD.
Untreated HMOD can progress from asymptomatic to symptomatic, resulting in overt CVD events.

Hypertensive Mediate Organ Damage (HMOD)

Includes damage to the heart, vasculature, brain, kidneys, and eyes
Both structural and functional changes due to hypertension can differ between men and women.

Blood Pressure Measurement

Systolic blood pressure (SBP): arterial blood pressure during systole (max pulsatile pressure).
- Measured at the onset of the first Korotkoff sound.
Diastolic blood pressure (DBP): arterial blood pressure during diastole (min pulsatile pressure).
- Measured at the time of disappearance of the Korotkoff sounds (fifth sound).
- Fourth sound is considered as DBP if no fifth sound is heard.
Inter-arm difference: SBP difference of >10 mmHg when measured sequentially in each arm.
Postural/orthostatic hypotension: decrement of ≥20 mmHg in SBP and/or ≥10 mmHg in DBP when measured in the standing position.

Office Blood Pressure Measurement

Office BP can be measured manually or with automated devices.
Automated office blood pressure can be conducted in a setting attended by a healthcare professional or unattended.
White coat hypertension: BP that is above the threshold for diagnosing hypertension in the office but below the threshold in home/ambulatory settings.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores key concepts related to hypertension, including risk factors, pathophysiology, and renal mechanisms involved in blood pressure regulation. Understand how essential and secondary hypertension can lead to serious health complications. Test your knowledge on this critical health topic.