Lec 14- Stroke and ischemic hearth disease Flashcards
Definition of stroke and TIA
- Insufficient blood to the brain due to a block (ischemic) or rupture of arteries (haemorrhagic)
- TIA- transient ischemic attack (temporary interruption)
Those at risk from stroke
- HTN
- Diabetes
- AF
- High cholesterol
- Smokers
- High alcohol intake
- Positive family history
- Often associated with older people 65+, but 25% occur in younger people
- Ethnicity also a risk factor: south Asian; African or Caribbean
Symptoms of stroke
- Sudden numbness or weakness of the face, arm or leg, especially if it occurs on one side of the body
- Sudden confusion, trouble speaking or understanding
- Sudden trouble seeing in one or both eyes, double vision
- Sudden trouble walking, dizziness, loss of balance or coordination
- Sudden severe headache
- F.A.S.T
Diagnosis and treatment of stroke (If ischemic)
-Diagnosis through brain imaging (CT scan) –> urgency dependant on presentation
IF ISCHEMIC:
-Alteplase therapy (if within 4.5 hours of stroke)
-Mechanical clot removal
-Decompressive hemicraniectomy (middle cerebral artery infarction)
-Immediately start anti-platelet therapy
AFTER: SALT assessment, stroke rehab and statin therapy
Treatment of stoke if Haemorrhagic
-Referal to neurology
-Surgery or conservative management depending on size of bleed and predisposing factors
AFTER: SALT assessment, stroke rehab and statin therapy
Monitoring following acute stroke
- Swallowing reflex
- O2 sat
- BM’s
- BP
- GCS
Angina
- The pain of angina is variously described as tightness and gripping sensation in the chest
- Pain may also be described in arm, neck, jaw, ear
- Symptom not a disease- usually due to underlying atherosclerosis
- Often but not always associated with exertional breathlessness
- Need to distinguish from non-cardiac causes of chest pain e.g. GI-reflux, psychological pain
- Brought on by exertion and stress
Prevalence of angina
- 1.5 million sufferers in UK
- Considered to affect 9% of males 55-64 and 5% of females. Age 65-74 14% male and 8% female
- 40-50% of angina patients have silent angina: estimated that 60-70% of all ischaemic episodes are silent
- Diabetics are most likely to have silent angina
Cardiac O2 supply and demand
- O2 supply: oxygenation of the blood + blood flow (microvasculature is autoregulated)
- O2 demand: ventricular wall tension + HR+ contractility (increased by sympathetic B-stimulation
- Double product = HR x SBP (demand)
- NB- triple product = aortic pressure x HR x ejection time
- NB- increase in ventricular wall tension and marked increases HR may reduce blood flow
Diastolic crunch
- Most coronary flow occurs during diastole
- Sub-endocardial regions receive least flow
- Sub-endocardial perfusion pressure = diastolic BP (DBP) - ventricular end diastolic pressure (VEDP)
- Pain is caused by high pressure during diastole
Classification of angina
ANGINA PECTORIS: (exertional angina)- angina of effort and or emotion
-Most common form
-the onset of pain is predictable (usually stress or exercise)
UNSTABLE ANGINA: ‘intermediate syndrome’ due to the breakup of unstable plaques causing embolism or thrombosis. may precede AMI
-Symptoms are more severe and last longer
-Symptoms may occur at rest; may also involve arterial spams
-Symptoms may be more frequent
Classification of angina (prinzmetals angina)
VARIANT ANGINA
- Caused by spasm of epicardial coronary arteries due- to electrical instability associated with arterial tone (in 25% of cases AT is not present)
- Varient angina can occur at rest or at night
- High incidence among cocaine users
- Arterial spasm is also likely if angina is variable threshold
Classification of angina (prinzmetals angina)
VARIANT ANGINA
- Caused by spasm of epicardial coronary arteries due- to electrical instability associated with arterial tone (in 25% of cases AT is not present)
- Variant angina can occur at rest or at night
- High incidence among cocaine users
- Arterial spasm is also likely if angina is variable threshold
Glyceryl Trinitrate (GTN)
Mode of action is due to liberation of NO, activation of guanyl cyclase and increased levels of c-GMP:
- Enzymatic conversion to NO involving thiols
- Ineffective if injected into coronary arteries
- Effective if administered systematically
- Sublingual administration
- Treatment of angina attacks
- S/E: headache, hypotension
- Recurring pain after 2 administrations= hospital
Other nitrate based therapies
ORAL
-Isosorbide dinitrate active SL and orally
-Isosorbide and dinitrate are usually modified release preps
-Tolerance does occur and is clinically significant- incorporate nitrate free period
-Normal preps of ISMN use BD or TDS
-MR preps of ISMN OD and ISDN use BD or TDS
TOPICAL
-Patched used for once daily application, usually when oral route unavailable
IV
-Emergency reduction of BP or ischemic pain
