Hypertension and Stroke Flashcards
What does normal blood pressure depend on?
Balance of cardiac output and peripheral resistance
What physiological mechanisms are involved in maintaining blood pressure?
Renin angiotensin aldosterone system
Autonomic nervous system
Also : genetics plays a role
What happens when low BP, blood volume and sodium plasma levels are detected?
Renin released
Renin converts angiotensinogen to angiotensin 1
ACE converts angiotensin 1 to angiotensin 2
Angiotensin 2 causes vasoconstriction and increased aldosterone
What are most cases of hypertension due to?
“essential hypertension” - problem with peripheral resistance, exact mechanism unknown - prolonged smooth muscle contraction
What would persistently high BP cause?
Stroke
Heart disease
Renal disease
Visual failure
What increases the risk of developing high BP?
Family history Afro - Caribbean Obese Diabetes Alcohol Smoking Sedentary life
What value is high BP?
Over 140/90 mmHg
How do we test BP?
Sphygmomanometer
Serial clinic readings
Ambulatory BP
Home testing
How is BP managed?
Lifestyle changes Weight loss Smoking cessation Reduce alcohol Exercise Diet
What drugs act on the RAAS?
Calcium blockers and diuretics stimulate renin
Beta blockers inhibit renin
ACE inhibitors inhibit ACE
Angiotensin 2 receptor antagonists (AIIRA) inhibit vasoconstriction in the arteries and inhibit aldosterone release from adrenal gland
What is the biggest modifiable risk for a stroke?
Hypertension
What is the burden of strokes?
Leading cause of hospital mortality
Second leading cause of death
Major cause of acquired disability
110,000 strokes per year - 1/3 will die, 1/3 will be disabled and 1/3 make a full recovery
What is a stroke?
A sudden onset of focal neurological symptoms related to the disruption of the vascular supply to a particular area of the brain, leading to tissue death
Infarction - 80%
Haemorrhage - 20%
Pattern of signs and symptoms is attributable to one part of the brain and a particular vascular supply
Name 6 transient focal neurological events?
Partial seizure Transient global amnesia Demyelination Hypoglycaemia Peripheral nerve compression Migraine
What is a TIA?
Transient ischaemic attack (Differs from stroke only in duration)
Brief episode of neurological dysfunction caused by focal brain or retinal ischaemia
Symptoms last less than an hour
Requires urgent attention
What % of strokes are preceded by a TIA?
23%
What should happen following a TIA?
Assessment within one week, and within 72 hrs if high risk
What is the ABCD2 score?
Predicts risk of stroke at 2 days A = age B = BP C = clinical - weakness / speech D = duration D = diabetes
What do the results of ABCD2 mean?
0 - 3 low risk
4 - 5 mod risk
6-7 high risk
Anything over 4 should be treated as if they’ve had a stroke
What is the Bamford clasification of strokes?
TACS - total anterior circulation stroke
PACS - partial anterior circulation stroke
LACS - lacunar stroke
POCS - Posterior circulation stroke
What comprises a TACS?
Extensive middle cerebral artery infarction
All of:
Contralateral hemiparesis
Contralateral homonymous hemianopia
Cortical higher function loss - dysphagia (dominant hemisphere), visuospatial (non dominant hemisphere)
What comprises a PACS?
Branch of the middle cerebral artery
Any 2 of the 3 components of TACS
What is lacunar syndrome?
Tiny deep infarcts, usually silent
Unsually internal capsule or pontine
Some symptoms - clumsy hands
What comprises POCS?
Ipsilateral cranial nerve defects Motor or sensory Disorder of conjunctive eye movement Cerebellar dysfunction Contralateral homonymous hemianopia
How can a stroke be treated?
PRIMARY PREVENTION - modify risk factors
ACUTE TREATMENT - thrombolysis as long as not due to haemmorhage!!
SECONDARY PREVENTION - lifestyle measures, thromboprophylaxis - anticoags , antiplatelets
REHABILITATION - restores neurological functionality
What is a stroke unit?
Multidisciplinary team Expertise in rehabilitation Regular in service training for staff Involvement of carers in patient care Observations Advice
What occurs on a stroke unit?
Swallow assessment Pressure sore prevention Hydration and nutrition BP management Active glucose monitoring Antipyretic treatment
What is a carotid endarterectomy?
Surgical removal of the fatty deposits that have built up in the carotid
What are the laws for driving after a stroke?
No driving for 1 month
Don’t have to notify DVLA in first month after stroke/TIA
Why is it good to keep BP high following a stroke?
Keep it raised for 2 weeks to maintain brain perfusion
