6 - Hypertension Flashcards
Blood Pressure equation
Cardiac output x SVR
Optimal BP
120/80
Normal BP
130/85
Grade 1 hypertension
140-159/90-99
Grade 2 hypertension
160-179/100-109
Grade 3 hypertension
> 180/>110
Hypotension
SBP <90mmHg
DBP <60mmHg
Postural Hypotension
SBP decrease in standing >20mmHg or DBP >10mmHg
Symptoms of hypotension
Dizziness Impaired cognition Lethargy Fatigue Angina
Hypertension
systolic is persistently >140 and diastolic persistently >90 mm Hg
Diagnose hypertension
Repeat BP measurements on separate occasions
24 hour BP monitoring
Concentric hypertrophy
size of the ventricle chamber decreases
To maintain cardiac output the heart rate must increase.
HT can cause this
Eccentric hypertrophy
whole ventricle enlarges (and the wall may or may not increase in thickness). The enlarged heart is weaker and this can lead to heart failure
Signs of damage to the retina caused by hypertension
Silver/copper wire arterioles - centre of arterioles shine due to reflected light
Micro aneurysms, swelling of optic disk
Secondary causes of hypertension
5% of all cases Renal disease Cushings syndrome Endocrine disease NSAIDs Thyroid disease
What % of hypertension is primary
95%
How is BP usually controlled
1) Baroreceptors in carotid artery
2) RAAS system
Where is the arbitrating mechanism located and what is it’s funciton
Medulla
Relieve conflicts between two control systems
Which BP control system is chronic hypertension associated with
RAAS
- elevated renin and angiotensin II
Why is dietary salt restriction part of hypertension treatment
high renin and angiotensin levels lead to excess sodium retention
Why are diuretics part of the hypertension treatment
high renin and angiotensin levels lead to retention of water (via raised ADH)
Hyponatremia
EC fluid Na+ is below 135mmol/L
Normal (135-145mmol/L)
can cause brain swelling
Symptoms of hyponatremia
Loss of energy, fatigue, confusion, muscle weakness
Severe - nausea, vomiting, headaches, spasms, restlessness,seizures, coma
Why do a majority of diabetes patients have hypertension
diabetes damages the kidneys and induces excess renin release
Why does obesity cause hypertension
Obesity increases renal renin release, angiotensin formation and sodium retention
High levels of leptin (due to increased number of fat cells) increase sympathetic vasoconstriction
Treatment for hypertension
1) Lifestyle changes - exercise and diet
2) Thiazide diuretic e.g bendroflumethazie
3) Diuretic + BB or ACE inhibitor
4) Angiotensin receptor blocker
5) Calcium channel blocker
(ABCD
Systolic BP
Maximum BP during ventricular contraction
Diastolic BP
Minimum level of BP measured between contractions of the heart
