* Stroke & Epilepsy Flashcards
What are neurological disorders?
Disorders of the brain, spinal cord and nerves
Classified into:
1) CNS disorders
2) PNS disorders
3) Blood vessel disorders
4) Tissue and muscle disorders
What are the possible causes of neurological disorders?
- Injury, trauma
- Infections
- Immunity conditions (eg myasthenia gravis)
- Inherited genetic abnormalities
What are the common neurological disorders / diagnosis?
- Cerebral vascular attack (CVA) ie stroke (3 types)
- Traumatic brain injury
- Brain infection
- Epilepsy/seizure
- Headache disorders
- Degenerative disorders
What are the 3 types of stroke?
- Transient ischemic attack (TIA)
~ Temporary disruption of blood flow to the brain -> temporary loss of neurological function
~ Blockage eventually gets removed on its own
~ <24 hours
~ No permanent damage on the brain yet but could be a sign of progressing disease - Ischemic stroke
~ Clot in the brain stops blood supply to that area, causing hypoxia
~ >24 hours - Hemorrhagic stroke
~ Blood leaking into brain tissue due to rupture of blood vessels
What are the symptoms of stroke?
FAST (Face, Arm weakness, Speech problems, Time to call 999)
- Sudden weakness of one side of the body (severity/reach of sensory loss varies p2p)
- Loss of sensation to touch
- Sudden blurred vision or loss of sight
- Sudden, severe headache
- Facial drooping
- Uneven smile
- Inability to answer questions but ability to understand them (Difficulty in answering complete sentences)
- Slurred speech
- Ability to write down thoughts more easily than speaking them
- Higher functions (eg memory, speech) affected depending on part of brain injured
- Sudden memory loss or confusion, dizziness or sudden fall
What are the risk factors of stroke?
- Male gender (females usually protected by certain hormones until menopause)
- Age, race, heredity
- Hypertension
- Diabetes
- HLD
- Vices
- Obesity
What are the factors affecting stroke?
1) Extra-cranial factors (outside brain, systemic)
- Systemic blood pressure (MAP)
- Cardiac output
~ High/low output cardiac failure
- Viscosity of blood
~ More viscous -> Flows slowly -> Increased risk of clots
2) Intracranial factors
- Intracranial pressure
- Atherosclerosis in blood vessels
- Injury to blood vessels in brain
What are the symptoms of TIA?
If carotid arteries are involved:
- Transient loss of vision on one eye
- Hemiparesis
- Inability to speak
If vertebrobasilar arteries are involved:
- Tinnitus
- Vertigo and blurred vision
- Hemiparesis
What is an infarction?
A small, localised area of dead tissue resulting from failure of blood supply/ischemia for more than a few minutes
What are the 2 causes of ischemic stroke?
1) Thrombotic
- Due to atherosclerotic plaque -> most dangerous
- Large vessel injury (eg Middle Cerebral Artery/MCA infarct)
- Small vessel injury (Lacunar infarct) –> S/s milder
- Blood disorders (eg thrombocytosis, polycythemia)
2) Embolic
- Dislodgement of blood clots from other parts of the body
- Carotid plaque (carotid artery link heart to brain)
- Atrial fibrillation
- Atherosclerotic plaques
How does atrial fibrillation lead to stroke?
- Atria beat irregularly and often rapidly, which can cause them to quiver rather than contract effectively -> prevents the atria from fully emptying their blood into the ventricles
~ Because the atria aren’t contracting properly, blood can pool in the atria -> increases the risk of blood clot formation
What causes the difference in s/s in ischemic stroke?
- Site of obstruction
~ Brain area supplied by the affected artery - State of circulation
~ Presence of good arteries in the adjacent area may provide collateral circulation - Onset
~ Sudden, during exertion (embolism)
~ Slow, during rest time (thrombosis)
What is the pathophysiology of ischemic stroke?
- Reduced blood flow in arteries due to thrombosis or embolism -> deprives cells of O2 and glucose
~ Lack of energy causes membrane dysfunction and entry of ions -> cytotoxic edema then death of cells
~ Vascular changes aggravate edema
Progression in brain
- Ischemia in one area -> moves on to penumbra (surrounding of stroke area) which remains viable for several hours after ischemic attack due to COLLATERAL ARTERIES supplying it
~ After some time, extent of penumbra decreases
- Ischemia and inflammation damages the BBB, allowing proteins and fluid to leak from `blood vessels into brain tissue (vasogenic edema)
~ ^ ICP and compresses brain structures further
What are the arteries in the brain that can be affected and cause ischemic stroke?
1) Anterior cerebral artery (in medial aspect of frontal lobes)
2) Middle cerebral artery (in most of the lateral cerebral hemisphere)
3) Posterior cerebral artery (in occipital lobe and medial aspect of temporal lobe)
4) Vertebro-basilar territory (group of arteries supplies parts of the posterior brain, including cerebellum)
What are the s/s for ischemic stroke when ACA is affected?
Superficial branches:
- Confusion, disorientation (prefrontal lobe)
- Paralysis and sensory loss in OPPOSITE leg
- Apraxia (difficulty with motor planning to perform tasks or movement)
- Abulia (lack of will or initiative, lack of motivation)
- Urinary incontinence
Deep branches:
- Well tolerated due to collateral flow
What are the s/s for ischemic stroke when MCA is affected?
Superficial branches:
- Paralysis of face and hand
- Conjugate gaze paralysis
- Motor aphasia (left-sided stroke)
- Conduction or sensory aphasia
- Construction of dressing apraxia
Deep branches:
- Paralysis of opposite side
What are the s/s for ischemic stroke when PCA is affected?
Superficial:
- Vision loss
- Memory loss
- Agraphia (impaired writing ability, either due to language or motor problems)
Deep:
- Thalamic syndromes
What are the s/s for ischemic stroke when vertebro-basilar territory is affected?
- Ataxia
- Intention tremor (low-frequency tremor that affects fine motor movements)
- Incoordination
- Cerebellar dysfunction
If brain lesion present:
- Crossed paralysis and sensory loss
What are the characteristics of cerebellar dysfunction?
- Ipsilateral lesion (affected side on the same side of cerebral lesion)
- Cerebellar ataxia
~ Wide-based staggering unstead gait - tends to fall on side side as lesion
~ Truncal ataxia - Intention tremor
~ Incoordination of arm and leg (despite voluntary)
~ Worse when approaching target
~ Finger-nose test, heel-shin test - Dysmetria
~ Error in judging distance -> overshooting
~ May be accompanied by tremor - Rebound phenomenon
~ Difficulty in stopping movement when resistance is withdrawn suddenly - Dysdiadochokinesia
~ Inability to perform rapid alternating opposite movement
~ eg Pronation-supination, ankle flexion-extension - Decomposition of movements
~ Inability to perform actions that may involve more than one joint simultaneously
~ Movement appears robotic - Nystagmus
~ Rapid uncontrollable eye movements - Scanning speech
~ Words are broken into many component sounds (staccato speech) - Hypotonia
~ Decreased muscle tone - Asthenia
~ Muscles are weaker and tire more easily than normal muscles
What are the different s/s in right vs left brain damage?
Right:
- Paralysed left side
- Spatial-perceptual deficits
- Quick and impulsive
- Memory deficits in performance
- Indifference to disability
Left:
- Paralysed right side
- Speech-language deficits
- Slow and cautious
- Memory deficits in language
- Distress and depression in relation to disability
What is the general treatment for ischemic stroke?
- Tissue Plasminogen Activator (tPA)
- Anticoagulant and antiplatelet therapy
- Carotid endarterectomy
~ Surgically remove plaque - Balloon angioplasty/stents
