week 1 brain- medical Flashcards
stroke
“Brain attack”: sudden impairment of cerebral circulation causing acute focal neurological disorder
Results in injury/death of brain tissue
ischamic stroke
Cerebrovascular obstruction by thrombosis or emboli
thrombotic stroke
Thrombosis of cerebral (typically atherosclerotic) vessel
Often at arterial bifurcations
Either:
Acute local thrombosis & occlusion at site of chronic atherosclerosis, (with or without causing distal plaque embolus)
Critical perfusion failure distal to stenosis (narrowing of vessel)
embolic stroke
Moving embolism that travels from it’s origin to brain
Most from thrombus in left heart
May also be from atherosclerotic plaque in carotid arteries
Travels quickly to brain, lodges in smaller artery & cannot pass
Usually sudden onset, immediate maximal deficit
Hemorrhagic stroke
Most frequently fatal stroke
Sudden spontaneous rupture of cerebral blood vessel
Often when patient is active
Focal haematoma, oedema & compression of brain contents
Immediate rise in ICP, exerts pressure on brain
Progresses rapidly to coma, & often, death
Either intracerebral or subarachnoid
Common predisposing factors are age & hypertension
Also trauma, tumours, blood coagulation disorders, vasculitis, & drugs.
Subarachnoid Haemorrhage
- Rupture of cerebral aneurysm; haemorrhage into subarachnoid space
- Commonly occur in the Circle of Willis
- Usually occurs without any prior symptoms, although associated with prolonged hypertension and arterial degeneration
- Mean age for subarachnoid haemorrhage is 50 years
- Mortality & morbidity high
intracerebral haemorrage
Sudden, severe headache
Decreased LOC
Hemiplegia
Possible seizures
Hypertensive atherosclerosis & cerebral amyloid angiopathy (CAA) responsible for 80% of haemorrhages
Poorly controlled hypertension often identified
Usually occurs during physical activity
stroke symptoms
Right brain: Paralysis on left side of body Vision problems Quick, inquisitive behavioural style Memory loss Left brain: Paralysis on right side of body Speech/language problems Slow, cautious behavioural style Memory loss
Facial Nerve (Bell’s) Palsy
Inflammatory disease of facial nerve (cranial nerve VII)
Causes inappropriate neural stimulation to muscle fibres controlled by facial nerve
Unilateral or bilateral facial weakness
Multiple causes (E.g. infection, tumour, trauma)
generalized seizure
Most common type of seizure Begin simultaneously in both hemispheres Involves unconsciousness & varying bilateral degrees of symmetric motor responses These seizures are divided into six categories: Tonic-clonic Absence seizure Myoclonic Clonic Tonic Atonic
Seizures
Temporarily abnormal behaviour caused by an electrical discharge from one or more groups of neurons in the cerebral cortex
Signs & symptoms vary according to site of neuronal discharge in the brain
Typically include sensory, motor, autonomic, or psychic phenomena
Most people experience first seizure episode pre 20 years old
focal (partial seizure)
-begin in specific area of cerebral hemisphere
-either discretely localized or become widely distributed.
Differentiated into two major groups:
Without impairment of consciousness
With impairment of consciousness/awareness
Generalised: Tonic-Clonic Seizures
-Tonic-clonic seizures most common major motor seizure
-Tonic-clonic phases usually last 60-90 seconds
Specific progression of events:
aura
loc
tonic phase
hypertonic phase
clonic phase
post seizure
postical
tonic phase
continuous muscle tension- contraction
hypertonic
extreme muscle rigidity
