Hypertension and Stroke

• Hypertension is elevated blood pressure. When measured by sphygmomanometer, listen to Korotkow sounds:

  • Systolic pressure (contracting) when sounds appear
  • Diastolic when they disappear

  Blood pressure shows variation throughout the day
• Level of blood pressure that constitutes hypertension:

  • Above 140/90 mmHg was the previous standard
  • Now tend to treat according to level of blood pressure and overall cardiovascular risk
• Measuring blood pressure:

  • Use device which is recommended by BHS (British Hypertension Society)
  • Pt should be sitting: at least 2 measurements - then take the average of those 2 readings
  • Ambulatory blood pressure monitoring
  • Variability between home and clinic
  • "White coat effect"
• Pathophysiology of hypertension:

  • Bursting effect
  • Cerebral haemorrhage
  • Dissecting aneurysm
  • Can have more insidious effects
  • CHD (coronary heart disease)
  • Stroke
  • Renal failure
  • Arteriosclerosis
• Aetiology of hypertension = essential hypertension in 90% of cases

  • Poly-causal
  • Essentially a diagnosis of exclusion
  • Multiple gene loci influence
  • Environmental factors: obesity, salt intake, and lack of exercise
• Secondary hypertension:

  • Commonest causes = renal
  • Renal artery stenosis (typically seen in older pts with vascular disease)
  • Endocrine causes
  • Conn's syndrome
  • Cushing's syndrome
  • Instrinsic renal disease eg glomerulonephritis

  
• Effects of elevated blood pressure:

  • Heart = increases risk of coronary heart disease (CHD)
  • LVH (left ventricular  hypertrophy), and possible arrhythmias
  • Aortic aneurysm
  • Peripheral vascular disease - arteriosclerosis
  • Cerebral circulation - increased risk of cerebral infarction and cerebral haemorrhage
  • Hypertensive encephalopathy - severe hypotension, coma and seizures
  • Eye changes
  • Blood vessels attenuated
  • Haemorrhages
  • Can be sight-threatening
• Complications of hypertension:

  • Myocardial infarction
  • Stroke
  • Cerebral infarction
  • Brain haemorrhage
  • Multi-infarct disease
  • Malignant hypertension
  • Hypertensive encephalopathy
  • Dissecting aortic aneurysm
  • Peripheral vascular disease
• Non-therapeutic treatment measures for hypertension:

  • Weight reduction
  • Exercise
  • Decrease salt intake
  • Alcohol reduction
• Treatment measures that reduce cardiovascular risk, but not blood pressure:

  • Stop smoking
  • Reduced saturated fat
  • Increase intake of oily fish
• Tailored treatment for hypertension:

  • Treatment should follow sensible lines
  • Should take account of patient other problems, likely side effects e.g. heart failure, diabetes - ACE inhibitor
• A stroke is a neurological deficit of a presumed vascular cause.
• A TIA (transient ischaemic attack) is a neurological deficit of presumed vascular cause - like a stroke, but lasts <24 hours.
• PRIND (prolonged reversible ischaemic neurological deficit) = like a TIA (transient ischaemic attack), but lasts longer than 24 hours.
• Stokes usually have a rapid onset of symptoms - same symptoms over weeks/months suggest alternative diagnosis

  
• Symptoms of a stroke:

  • Paralysis
  • Loss of sensation
  • Double vision
  • Unsteadiness
  • Loss of speech
  • Loss of ability to use and understand language
• Stroke symptoms depend on what part of the brain is affected, and what part of the brain is affected depends on the arterial territory affected.

  
• Prevalence of risk factors for strokes:

  • Hypertension - 52%
  • Vascular disease elsewhere - 38%
  • Smoking - 45%
  • Diabetes - 10%
  • TIA (transient ischaemic attack) - 14%
  • Atrial fibrillation - 5%
• Treating raised blood pressure reduces the risk of stroke in those who are at risk of stroke and those who have had a stroke/TIA (transient ischaemic attack) before.
• Forms of stroke prevention:

  • Surgery - for pts with narrowed carotid arteries
  • Aspirin and other anti-platelet drugs
  • Lower cholesterol
  • Warfarin (dental treatment ok if INR <4)
  • In pts with atrial fibrillation (irregular pulse)
  • Or other cardiac source