Week 4 - Strokes Flashcards
Explain the basics of cerebral blood supply:
- 80% from internal carotid arteries (ICA) which feed into the circle of willis
- Remaining 20% from the posterior circulation
What are the S/S of stroke?
- limb weakness or paralysis
- facial paralysis
- sensory loss
- slurred speech (dysarthria)
- Inappropriate or jumbled speech (dysphasia)
- Visual loss (hemianopia)
- Gaze deviation
- Poor balance, unsteady gait (ataxia)
- Difficulty swallowing (dysphagia)
- Double vision (diplopia)
- 80-90% have some motor deficit at stroke onset
Explain the assessment and management of a stroke pt?
National Institute of Stroke Scale is gold standard - 11 elements of neurological impairment e.g. LOC, orientation, commands, eye movements
Alteplase is the drug used in thrombolysing stroke: criteria incl. clear onset within 4.5hrs, measurable and clinically significant deficit, CT doesn’t show haemorrhage or non-vascular cause of stroke
Explain the basics and causes of Intracerebral Haemorrhagic stroke and Subarachnoid:
- Intracerebral: Caused by the rupture of a diseased small intracerebral vessel, at least 50% caused by HTN, which accelerates atherosclerosis; bleed results in raised ICP, can result in coma as brain stem compression occurs
- Subarachnoid: usually rupture of saccular (berry) aneurism; thunderclap headache usually followed by LOC, lethal in up to 50% at first rupture
What are the key findings and history of SAH?
Severe, sudden onset headache is cardinal feature
Neck stiffness, photophobia and low back pain due to inflammatory response to blood in subarachnoid space
N/V, may have LOC, 10-15% suffer seizures, 10-15% suffer symptoms before rupture
20% associated with activities such as defecation, coitus and lifting
What are the 5 grades of SAH?
- Mild headache with/without meningeal irritation
- Severe headache and a nonfocal examination, with/without mydriasis
- Mild alteration in neurological exam, incl. mental status
- Obviously depressed LOC or focal deficit
- Patient either posturing or comatose
What is a TIA?
Episode of cerebral or retinal dysfunction resulting from inadequate supply of blood to the brain.
If everything has resolved in <24hrs without intervention considered to be TIA
What are impacts of damage to the Right hemisphere?
Problems with movement on left side of body, lack of feeling on left, trouble thinking clearly, solving problems or concentrating, impulsive behaviour, trouble estimating distance/size, decreased facial expression
What are impacts of damage to the Left hemisphere?
Problems with movement on right side, trouble speaking or understanding, trouble reading/writing/listening
What are impacts of damage to the Cerebellum?
Dizziness, loss of balance, loss of coordination, slurred speech, N/V
What are impacts of damage to the Brain stem?
Brain stem connects the 2 hemispheres with spinal cord, therefore both sides of body may be effected.
Some changes: coma, total paralysis, problems with speech/swallowing, double vision, N/V, hiccups
What are some stroke mimics?
- Electrolyte disturbances (Na+, K+, Ca2+)
- Hypoglycaemia or hyperglycaemia
- Seizures (absence, post ictal states)
- CNS infections (encephalitis)
- Brain tumour
- Syncope
- Middle ear (vestibular) disorders
- Stress
- Migraine
- Systemic infection (sepsis)
- Intoxication (drugs or alcohol)
- Trauma (subdural haematoma)
What are the risk factors for stroke?
HTN Diabetes Ischaemic heart disease Smoking Age and gender Race and ethnicity
Define stroke:
Any disturbance of cerebral function (>24 hrs) caused by abnormalities of blood vessels. - estimated 1.9 million neurons/min lost
What are the different types of stroke:
- Ischaemic (85%): thrombotic, embolic, hypoperfusion
- Haemorrhagic (15%): intercerebral, subarachnoid, extradural, subdural
- Transient Ischaemic Attack
