10.6 Cerebrovascular Diseases Flashcards
Define stroke
- A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot or bursts (or ruptures). When that happens, part of the brain cannot get the blood (and oxygen) it needs, so it and brain cells die
WHO
Stroke was defined by the World Health Organization (WHO) more than 40 years ago as “rapidly developing clinical signs of focal (or global) disturbance of cerebral function, lasting more than 24 hours or leading to death, with no apparent cause other than that of vascular origin
Define TIA (transient ischeamic attacks)
- Acute neurological event due to a vascular cause lasting less than 24 hours
…but most resolve within an hour
What are the 3 big problems that strokes cause?
- disability (leading cause of disability)
- dementia
- mortality
Define
Oligaemia
Penumbra
Infarction
Oligaemia = ↓ blood flow, but normal function
Penumbra = neurological fallout but potentially viable tissue SNL = Selective Neuronal loss
Infarction = Neurological fallout, cells have died
Types strokes
- Obstruction in artery ➡️ Ischaemic stroke
- Rupture of blood vessel ➡️ Hemorhagic stroke (blood leaks into brain and surrounding tissue)
- Venous sinus thrombosis (thrombus in venous structure: superior sagittal sinus)
List the Causes of stroke
- Haemorrhage 20%
- Ischaemia 80%
Haemorrhage causes
- Hypertensive bleed
- Aneurysms eg SAH -> subarachnoid haemorrhage
- Vascular Malformation - AV
- Tumour
- Bleeding diathesis
- Cerebral Amyloid Angiopathy – Lobar haemorrhages (in elderly) rare
- Haemorrhagic transformation of an ischaemic OR venous infarct
Ischemia causes
Common
- Cardiac origin of emboli: 20-30%
- Atherosclerosis (thrombo-embolic): 25%
- Small vessel disease: 20% (Hypertension; Diabetes; Smoking; Alcohol)
- No cause found: 20% [younger pt]
Less common -> Virchows Triad
- Nonatherosclerotic vasculopathy: 5-10% {vessel wall}
➡️Fibromuscular Dysplasia
➡️Carotid & vertebral dissection 6-10% patients 30-50y
➡️Arteriitis: (Takayasu, isolated CNS angiitis, SLE, Wegeners, HIV, infective causes)
- Hematological causes: 5% {constituents}
➡️SC disease, Hemoglobin SC disease, PNH
➡️Polycythemia / Thrombocytosis / Leukaemia
➡️TTP / DIC / Disorders of fibrinolysis
➡️Pregnancy, Cancer, Nephrotic syndrome, acute infection,..
➡️Hypercoagulable states
➡️Antiphospholipid syndromes
- Hyperhomocysteinemia
Causes of stroke in the young
- cardiovascular myelopathy
- haemotological conditions
- drugs
Illicit drug use
- Present in up to 12%
- Varies by location and drug type
- Consider tox screen
- IV drugs can produce embolisation of foreign material or
- Endocarditis
- Drugs with a sympathomimetic effect (amphetamine, cocaine, crack) can cause ischaemic stroke through several mechanisms such as:
➡️acute hypertension
➡️enhanced platelet aggregation
➡️and rarely vasculitis (mainly related to amphetamine intake) of the periarteritis nodosa or giant cell-granulomatous types
Sources of emoboli
- Left atrium
- Left ventricle
- Aorta
- Carotid
Risk factors for strokes
- history of hypertention
- physical inactivity
- waist-to-hip ratio
- smoking
- diet risk
- cardiac causes
- diabetes
- depression
- alcohol intake
- psychosocial stress
all of them are modifiable
Cardio-Embolic stroke
Risk factors
Risk factors
- mechanical cardiac valves,
- dilated cardiomyopathy,
- myocardial infarction (AMI) within the last month left ventricular or - atrial thrombi,
- infective endocarditis
Atrial fibrillation & Stroke
- The most common arrhythmia
- 1 of 6 strokes are due to AF (1 in 3 of pts > 80)
- In patients with non valvular AF the stroke risk varies 1-14% per year
- Rheumatic heart disease patients have a 17-fold increase compared to age-matched controls
- Recent data suggests a significant proportion of cryptogenic stroke is due to paroxysmal AF
Stroke etiology
Toast classification
- atherothrombotic
- cardioembolic
- lucunar / small vessel
- other / uncommon
- cryptogenic
