Stroke Flashcards
To learn about stroke
How is Stroke defined?
Clinical syndrome of rapidly developing clinical signs of focal disturbance of cerebral function, lasting more than 24h, or death with no apparent cause other than that of vascular origin.
What is a TIA?
A transient ischaemic attack (TIA) is defined as a stroke and symptoms that resolve within 24h
How does stroke come about?
- Cerebral infarction (84%)
- Secondary to thrombosis (54%)
- Embolus (31%)
- Primary intracerebral haemorrhage (10%)
- Subarachnoid hemorrhage (6%)
How is a non disabling stroke defined?
A stroke with symptoms that last for more than 24 hours, but later resolve leaving no permanent damage
What are the approaches to thinking about stroke?
Anatomically:
1. With respect to vascular territory
2. With respect to the cerebral structures affect
Pathologically
What are the modifiable risk factors for stroke?
- Hypertension
- Smoking
- AF
- DM
- Diet, XS alcohol
- Obesity, little exercise
- Raised cholesterol
What are the non modifiable risk factors for stroke?
- Increasing age
- Male gender
- Afro-caribbean descent
- Hx of stroke in family
What is the aetiology of thrombotic stroke, affecting major arteries?
- Atherosclerosis
- Dissecting aneurysm (especially in the young)
- Fibromuscular dysplasia
What is the aetiology of thrombotic stroke affecting the small vessels?
- Hypertension
- Arteriosclerosis
- DM
What hypercoagulable states contribute to thrombotic stroke?
- Congestive heart failure
- Polycythaemia
- Thrombocythaemia
- Malignancy: myeloma, leukaemia
- Sickle cell disease
- Pregnancy, oral contraceptive
- Anti phosholipid syndrome
What is the aetiology of an intercranial haemorrhage?
Rupture of Charcot-Bouchard aneurysms is the main cause.
What are other causes of Inter cerebral haemorrhage?
- Arterial rupture maybe spontaneous
- 50% of ICH no history of high BP
- Drugs: amphetamine, cocaine
What further causes if ICH?
- Amyloid angiopathy: third of cases in elderly
- Vascular malformations:
- Bleeding diastheses: thrombocytopaenia, leukaemia, haemophilia,
- Anticoagulant therapy
- Head injury
What is the aetiology of a subarachnoid heamorrhage?
- 80% due to Berry aneurysm
- 10-15% due to other aneurysms:
(i) arteriosclerotic
(ii) inflammatory
(iii) traumatic - 5% due to arteriovenous malformations
- Bleeding diastheses, tumours
What are the clinical features of a stroke?
- Sudden onset hemiparesis in person > 60
2. Focal brain may reflect distribution of affected artery
What are the clinical features of a cerebral hemisphere infarct?
- Contra lateral hemiplegia: limb first becomes flaccid then spasticity
- Homonymous hemianopia
- Sensory loss
- Dysphagia
- Upper motor neurone signs
Describe an anterior cerebral artery stroke?
- Occlusion of the anterior cerebral artery by embolus or thrombus.
- Effects may depend on site of occlusion
What is the anatomy of the anterior cerebral artery?
- The anterior cerebral artery. is a branch of the internal carotid
- Deep branches passes to the internal capsule and basal nuclei
- Cortical branches supply the medial surface of the orbital, frontal and parietal lobes
What are the clinical features of the anterior communicating artery when the occlusion is proximal?
Occlusion proximal to the anterior communicating artery is often well tolerated due to collateral flow
What are the clinical features when there is a proximal occlusion when both arteries arise from the same anterior cerebral stem?
- Paraplegia, usually of both limbs
- Sensory loss
- Incontinence
- Mental symptoms
- Grasp, snout and pout reflexes
What are the clinical features of an anterior communicating artery infarct when the occlusion is distal?
- Contralateral hemiplegia/hemisensory loss of lower limbs with upper limbs spared
- Occasionally a contralateral grasp reflex
Describe a middle artery stroke?
- The middle cerebral artery maybe occluded by thrombus or embolus
- TIA in MCA produce a transient hemiparesis in association with dysphasia
What is the anatomy of the middle cerebral artery?
- The MCA is the largest branch of the internal carotid artery.
- Gives off branches to anterior limb of internal capsule and basal nuclei.
- Gives branches to temporal, frontal and parietal structures.
- A rough approximation of the distribution may be obtained by placing a hand over the side of one’s own head, with fingers spread and pointing forwards
What are the clinical features of an occluded middle cerebral artery?
- Contra lateral hemiplegia: face tongue, upper limb affected leg spared (ish)
- Contralateral hemisensory loss/hemianopia
- Neuropsychological fx:
(i) Neglect of Contralateral limbs and dressing
ability
(ii) Global dysphasia and Gerstmann’s synd
