Stroke and sub-arachnoid haemorrhage

HideShow resource information
  • Created by: z
  • Created on: 15-03-16 18:00

Stroke

  • WHO definition- neurologicla deficit of sudden onset, w/ focal rather than global dysfunction, in which symptoms presumed to be of no-traumatic vascular origin and last for >24hrs
  • 110,000 people have first stroke each year w/ 7% per aunnum risk of further stroke
    • 10,000 people <55yrs, 1000<30yrs
  • 3rd leading cause of death (67,000/year)
  • pathological classification:
    • cerebral infarct - 81%
    • primary intracerebral haemorrhage - 10%
    • SAH - 5%
    • other - 5%
1 of 9

Cerebral infarct

  • mean CBF 50ml/100g/min
    • 10-20ml/100g: electrical failure, penumbra part of injury (ischaemic but still functional)
    • <10ml/100g: metabolic failure, core part of injury
    • penumbra is progressively recruited to core- 1.9million neurones lost/min
  • mechanisms of infarct:
    • large artery atherothrombosis
      • cholesterol plaque rupture (acute clot superimposed on chr. stenosis) 
    • cardioembolic stroke- e.g. from AF
    • lacunar strokes
      • occlusion of small, perferator arteries; involves deep white matter and brainstem
      • RFs: HTN, DM, hyperlipidaemia
    • cryptogenic strokes
    • other: carotid dissection, vasculitis, endocarditis
  •  CT- infarcts are dark (low attenuation), difficult to see initially (loss of grey/white matter differentiation, sulcal effacement), develops over period of days, eventually well demarcated and dark- same as ICH strokes
2 of 9

Non-traumatic ICH

  • mechanisms
    • primary (80%)
      • chronic HTN, amyloid angiopathy (+amyloid deposits in vessels)
    • secondary 
      • vascular abnormalities (AVM, aneurism, cavernoma "berry appearance", venous angioma)
      • tumour
      • impaired coagulation (e.g. warfarin Rx)
      • vasculitis
      • drug induced
  • CT
    • bright 'high attenuation' due to Hb content
    • immediate appearance but becomes isodense after a few days
    • oft surrounded by low attenuation area of oedema and necrosis
    • mass effect is common (midline shift etc)
3 of 9

Extradural/subdural haemorrhage

  • extradural 
    • oft due to # of pterion, temporal/parietal and disruption of MMA/V
    • blood between bone and dura
    • no LOC on trauma, lucid interval (hrs to days) then sharp deterioration
    • vomiting, headache, fits, confusion
    • lens shaped haemotoma on CT
  • subdural
    • bleeding of bridging veins b/w cortex and sinuses
    • esp in old people, alcoholics, epileptics 
    • blood b/w dura and arachnoid
    • crescenteric shape on CT- mid line shift
    • fluctating GCS, unsteadiness, headache, gradual mental slowing
4 of 9

Anterior circulation syndromes

  • anterior circ synrdomes- due to ACA, MCA, carotid occlusion
    • dominant (usually left cortex)
      • contralat weakness/numbness in arm, face, leg
      • contralat upgoing plantar and brisk reflexes
      • contralat homonymous hemianopia
      • aphasia (Broca's, Wernicke's, both)
    • non-dominant (right cortex)
      • contralat weakness/numbness in arm, face, leg
      • contralat upgoing plantar and brisk reflexes
      • contralat homonymous hemianopia
      • apraxia
      • contralat neglect
    • carotid dissection: (triad: need 2/3) (commonest cause of young stroke)
      • unilateral pain (face, head, neck)
      • Horner's syndrome
      • anterior circ stroke or TIA
5 of 9

Lacunar sydrome

  • infarc of small penetrating art in pons and basal ganglia or deep (subortical) haemorrhage
    • contralat hemiplegia
    • contralat hemisensory loss
    • contralat upgoing plantar
    • NO cortical signs (hemianopia, dysphasia, apraxia, neglect)
  • assoc w/ chronic HTN
6 of 9

Posterior circulation syndrome

  • Posterior cerebral artery infarct or occipital haemorrhage
    • often unnoticed by pt
    • contralat homonymous visual field defect (b/c CNII lesion before chiasm)
  • cerebellar infarction/haemorrhage
    • nausea, vomiting, loss of balance, vertigo, headache
    • DANISH- Dysdiadochokinesis & Dysmetria (past-pointing), ipsilat Ataxia, Nystagmus, Interntion tremor, Scanning dysarthria, Heel-shin incoordination
    • risk of obstructive hydrocephalus and coma
  • basilar artery occlusion
    • bi/unilat CN palsies
    • severe quadriplegia
    • bilat upgoing plantars
    • coma, resp arrest
    • locked in syndrome: complete m. paralysis except upward gaze
7 of 9

TIA

  • stroke syndrome resolves <24hrs
    • mean carotid territory TIA - 14mins
    • mean vertebral artery TIA - 8mins
  • 10% will have stroke in next 90 days (5% in next 2 days)
  • sudden onset of focal signs
    • motor, expressive dysphasia, amaurosis fugax
      • amaurosis fugax: retinal art occlusion, transient monocular blindness 1-5mins, moves peripheral to centre, painless (headache-migraine or temporal arteritis)
    • hemianopias, hemisensory symtpoms
    • diplopia, vomiting, vertigo, dysarthria, dysphagia, ataxia
  • almost never cause:
    • global symptoms (e.g. syncope, dizzines)
    • migrainous symtpoms (headache, visual disturbances)
    • buring or pain in limbs
    • recurrent falls
    • seizure-like symptoms
8 of 9

Subarachnoid haemorrhage

  • causes:
    • ruptured aneurysm (85%)
    • perimesencephalic (10%)
    • rare causes (5%)
      • Wegner's, dissection, AVM, cavernoma, sickle cell disease, coagulopathies, tumours, cocaine, warfarin
  • thunderclap headache (85-100%)
    • any location, onset to peak w/in 5 min
    • DDx- meningitis, venous thrombosis, ischaemic stroke, acute HTN crisis
  • assoc features
    • vomiting (75%)
    • depressed consciuosness (67%)
    • precipitating factor (20%)- sex, exercise
    • subhyaloid haemorrhage (14%)
    • neck stiffness
    • preceeding headache 
9 of 9

Comments

No comments have yet been made

Similar Medicine resources:

See all Medicine resources »See all Neurology resources »