L3: Hypertension

Question 1

Where is systolic blood pressure measured?

Answer 1

Brachial artery of the arm

Question 2

What are the classifications of normal, prehypertensive and hypertensive blood pressure?

Answer 2

Normal = 90 - 119 systolic / 60 - 79 diastolic 
Prehypertensive = 130 - 139 systolic / 80 - 89 diastolic 
Hypertensive = >140 systolic / >90 diastolic

Question 3

What is the statistic of global hypertension and what about predicted levels in 2025?

Answer 3

Approximately 25% of global population is hypertensive and is predicted to reach 30% by 2025 (Kearney et al, 2005)

Question 4

Explain the prevalence of hypertension in terms of gender, country and age?

Answer 4

Hypertension is more prevalent in women beyond the age of 50.
Hypertension is more prevalent in low socio-economic countries which implicate westernised lifestyle
Hypertension is predominately a condition that effect older individuals, with very little effect on individuals below the age of 30.

Question 5

Why do women have higher prevalence of hypertension than men

Answer 5

1. Menopause reduces oestrogen production, a hormone involved in blood pressure regulation
2. Women live longer than men, thus survivorship means a larger population of older women will have hypertension
3. Most studies where done on men so treatment and guidelines may be better suited to men.

Question 6

What are the short term methods of blood pressure regulation?

Answer 6

1. SNS epinephrine
2. ANS baroreceptor feedback and the activation/inhibition of vasomotors and cardioacceleratory/cardioinhibitory
3. Nitric oxide
4. Endothelin-1

Question 7

What are the long term methods of blood pressure regulation?

Answer 7

Renin-angiotensin system:

1. Kidneys release renin which converts angiotensinogen into angiotensin 1.
2. Angiotensin I is converted to angiotensin II via angiotensin converting enzyme (ACE)
3. Angiotensin II is responsible for vasoconstriction of blood vessels, encourages the release of aldosterone which increases kidney water and sodium resorption.

Question 8

What are the different types of hypertension?

Answer 8

1. Essential hypertension
2. Secondary hypertension
3. Pulmonary hypertension
4. Pre-eclampsia (pregnancy)

Question 9

What is the INTERSALT STUDY (Dyer et al, 1989)?

Answer 9

Cross-sectional study looking at the relationship between body weight and blood pressure. Identified that 10kg of body weight increased systolic blood pressure by 3mmHg and diastolic by 2.2mmHg. 30% of hypertension cases can be attributable to obesity.

Question 10

What was the study from Neter et al, 2003?

Answer 10

Meta-analysis on weight loss and blood pressure, and identified an average reduction of 4.4 mmHg systolic and 3.6mmHg diastolic for every 5kg weight loss.

Question 11

What are the possible reasons for why weight loss reduces blood pressure?

Answer 11

1. Adipocytes produce leptin which reduces hunger but also increases sympathetic nervous activity causing the release of epinephrine which causes vasoconstriction.
2. Leptin also over stimulates the renin-angiotensin system leading to sodium reabsorption increasing blood pressure.
   - Renin activity and aldosterone is higher in obese individuals.