Week 8: Acute Neurological Deterioration Flashcards
What are some causes of unconsciousness?
Decreased oxygen to brain Decreased BP Hypo/hyperglycaemia Opiates Seizures Infection Toxins MODS Alcohol
How does hypoxia cause cerebral oedema?
Inadequate O2 to brain inhibits production of ATP necessary for Na-K pump to move Na out of cells. As Na builds up in brain cells, water is drawn in as well by osmosis, causing cytotoxic cerebral oedema
How can carbon dioxide affect cerebral blood flow?
Hypercarbia –> cerebrovascular vasodilation
Hypocarbia –> cerebrovascular vasoconstriction
Vasodilation increases ICP
What is the Monro Hellie Hypothesis?
Brain, intravascular volume and CSF are in dynamic equilibrium. If one component icnreases in volume then another must decrease otherwise ICP will increase
What are compensatory mechanisms for volume-pressure changes in the intracranial space?
Displacement of CSF to spinal subarachnoid space
Compression of low pressure venous system
Decreased CSF production
Vasoconstriction
What are factors which affect cerebral blood flow?
CO2
O2
Blood vessel integrity (multi infarct dementia)
Blood viscosity
Other: arousal and pain, seizures, hyperthermia, REM sleep
What is a Cushing response?
Ischemia to brain stem:
Elevated SBP
Widening pulse pressure
Bradycardia
Why is temperature an important sign in neurological conditions?
Hyperthermia:
Lesions of hypothalamus
Petechial haemorrhage
Infection
Hypothermia:
Spinal shock (vasodilation)
Exposure
Lesions on brain stem tract
What metabolic problems can cause seizures?
Acidosis Electrolyte imbalance Hypoglycaemia Hypoxia Alcohol or barbiturate withdrawal Dehydration Water intoxication
What extracranial disorders can cause seizures?
Heart, lung, kidney or liver disease
NIDDUM
HTN
Sepsis
What are some typical assessment findings of a person with a seizure?
Aura LOC Incontinence Tachycardia Diaphoresis Tonic clonic movements
Post ictal:
Lethargy
Reduced LOC
Confusion and headache
What is the emergency management for a person with a seizure?
Protect from injury Do not force jaw open or restrain Remove loose or tight clothing Stay with patient Suction if needed Observe length of seizure, precipitating events Conduct A-G
What is delirium?
Sudden, transient and organic: confusion, disorientation, agitation, disturbed sleep or hallucinations
Who is at risk of delirium?
➢ Older adults ➢ People who have been in ICU ➢ Use of physical restraints ➢ Pain ➢ Emotional stress ➢ Sleep deprivation ➢ Immobility ➢ Visual or hearing impairment ➢ People on anticholinergic drugs ➢ People on multiple drugs ➢ Sedatives ➢ Alcohol withdrawal ➢ Drug withdrawal
What are common precipitating factors for delirium?
➢ 1/ Hypoxia ➢ 2/ Hypotension ➢ 3/ Hypoglycaemia ➢ 4/ Major electrolyte disturbance ➢ 5/ All of medication history ➢ 6/ Infections ➢ 7/ Urinary retention ➢ 8/ Constipation or faecal impaction ➢ 9/ Thirst, hunger, pain ➢ 10/ Alcohol withdrawal
What are the 3 subtypes of delirium?
Hyperalert: Restless Agitated Oversensitive to stimuli Hallucinations
Hypoalert:
Lethargy
Slowness
Reduced speech
Fluctuating symptoms:
Alternating between hyper and hypo
How do you manage delirium?
Prevention: anticipate precipitating factors and reduce them, regularly assess
Reverse cause
Non-pharma: fluids and nutrition, ambulation, optomise senses, sleep
Pharma: pain management, constipation management, psychotropic medication
What is a stroke?
Sudden interruption of blood flow to a part of the brain, killing the cells and destroying/impairing the functions controlled by that part of the brain
What is the difference between a haemorrhagic and ischemic stroke?
Haemorrhagic: rupture of blood vessel damages surrounding tissue
Higher mortality
Ischemic: embolism or thrombus obstructs cerebral artery which blocks blood flow to part of the brain
More common
What are the types of haemorrhagic stroke?
Intracerebral: bleeding into brain tissue due to ruptured small artery
Subarachnoid: bleeding into subarachnoid space due to ruptured aneurysm or anteriovenous malformation
What is stenosis?
Gradual process of atherosclerotic plaque accumulating in cerebral artery and occluding it. Ischemia and neurological deficits occur over hours to days
What is a thrombotic stroke?
Blood clot formed in cerebral blood vessel and blocks blood flow
What is an embolic stroke?
Embolus travels from a distant site and is caught in cerebral blood vessel
Sudden deficit
AF: blood pools in atria, clots and travels to cerebral artery
Atherosclerosis: plaque breaks off and travels to cerebral artery
What occurs during an ischemic stroke?
Blood flow interruption
After 4-5 minutes, cellular metabolism ceases:
O2, glucose and glycogen cannot be delivered to cells
No ATP
No Na-K pump
Na builds up in cells, attracts water –> cell swells
Blood vessel walls also swell, further diminishing blood flow
Cytotoxic oedema
Electrical paralysis
Excessive glutamate-calcium influx and oxygen free radicals further damage cells
What are the two zones of an ischemic stroke?
Primary zone:
Cell death, cannot be salvaged
Secondary zone: supplied by collateral blood flow, cells intact although have minimal metabolic activity
Affected by reduced blood flow, oedema and toxic substances released by damaged cells
Need to maintain airway, circulation and administer TPA
What is a transient ischemic attack?
Lasts less than 24 hours
Warning that stroke may occur in near future
Medical emergency
What are the signs and symptoms associated with a stroke on the left side?
Right hemiplegia Expressive, receptive or global aphasia Intellectual impairment Slow or cautious behaviour Defect in right visual fields
What is aphasia?
Impairment of language
Expressive: talking
Receptive: understanding
Global: both
What are the signs and symptoms associated with a stroke on the right side?
Left hemiplegia Spacial-perceptual deficits Unilateral neglect Distractibility Impulsive behaviour Poor judgement Defects in left visual fields
What is unilateral neglect?
Not recognising a limb on one side of your body
What are the signs and symptoms of an occlusion in the internal carotid artery?
➢ Contralateral paralysis of the arm leg and face
➢ Contralateral sensory deficits of the arm leg and face
➢ Aphasia (dominant hemisphere)
➢ Apraxia, agnosia unilateral neglect (non-dominant hemisphere)
➢ Homonymous hemianopia
What does ‘contralateral’ mean?
The side of the body opposite to that on which a particular structure or condition occurs
What is agnosia?
Inability to interpret or process sensory information
What is apraxia?
Difficulty planning motor movements
What is homonymous hemianopia?
Loss of one half of the visual field in each eye
What are the signs and symptoms of an occlusion in the ophthalmic artery?
➢ Amaurosis fugax
➢ Transient greying and fogging or blurred vision
➢ A ‘shade’ descending over line of vision
What is amaurosis fugax?
Painless temporary blindness in one or both eyes
What are the signs and symptoms of an occlusion in the middle cerebral artery?
➢ Hemiparesis (more arm than leg)
➢ Hemianaesthesia
➢ Contralateral motor or sensory deficits to face or limbs
➢ Aphasia (if the dominant hemisphere is involved)
➢ Apraxia, agnosia unilateral neglect (non-dominant hemisphere)
What are the signs and symptoms of an occlusion in the anterior cerebral artery?
➢ Contralateral hemiplegia (foot and leg)
➢ Impaired gait
➢ Sensory - toes, foot, leg
➢ Flat affect (lack of spontaneity, slowness, distractibility
➢ Cognitive impairment – inability to make decisions
➢ Urinary incontinence
What are the signs and symptoms of an occlusion in the vertebral artery?
➢ Dysarthria ➢ Dizziness ➢ Nystagmus ➢ Dysphagia ➢ Diplopia ➢ Bilateral blindness ➢ Ipsilateral numbness and weakness of face ➢ Clumsiness ➢ Pain in face, nose and eyes
What is dysarthria?
Slurred or slow speech
What is nystagmus?
Rapid and involuntary eye movement
What is diplopia?
Double vision
What does ipsilateral mean?
Same side of body
What are the signs and symptoms of an occlusion in the basilar artery?
➢ Quadriplegia
➢ Locked in syndrome
➢ Weakness of face, and pharyngeal muscles
What are the signs and symptoms of an occlusion in the cerebellar arteries?
Ataxia
Vertigo
Dizziness
How do you assess a person with a suspected stroke?
A-G
History: activity during onset, time of onset, health history, lifestyle and risk factors
Neurological assessment
What is the nursing management for a patient with a stroke?
A: semi fowlers to prevent obstruction
B: O2 if hypoxic
C: do not lower BP unless severe (>220/110), continue existing hypertensives unless hypotensive, control arrhythmias
D:
E: monitor 4 hourly, >37.5 remove blankets etc, 1g paracetamol, > 38 alert medical team, tkae MSU, blood culture, CXR
F:
G: monitor 6 hourly, maintain within 5-10 mmol/L
Swallowing assessment and management
Why is BGL control important for a person with stroke?
Hyper associated with poor outcome
Hypo can lead to further brain injury
What are the 3 phases of swallowing?
Oral (preparatory and oral phase)
Pharyngeal
Oesophageal
What is the oral phase of swallowing?
Mastication: mechanical breakdown, mixed with saliva to form bolus
Food voluntarily pushed into pharynx
Soft palate blocks nasopharynx
What can affect the oral phase of swallowing/what are signs of dysphagia at the oral phase?
Weakened facial muscles: leaking, dribbling, poor mastication
Inadequate salivation: bolus formation
➢ Facial asymmetry, tongue weakness, inability to close lips
➢ Weak or absent gag
➢ Loss of sensation to the oral cavity
➢ Drooling, pocketing, excessive chewing, nasal drainage
What is the pharyngeal phase of swallowing?
Involuntary reflex triggered by bolus passing over back of pharynx
Involuntary
Pharyngeal muscles propel bolus into oesophagus
Tongue and pharangeal folds block oral cavity
Larynx lifts up and forward to become blocked by epiglottis
What are signs of dysphagia at the pharyngeal phase?
Delayed or absent swallowing, coughing, history of aspiration, wet gurgling voice, frequent clearing of throat
What is the oesophageal phase of swallowing?
Wave of peristalsis which propels bolus through oesophagus to stomach
What are signs of dysphagia at the oesophageal stage?
Burning or substernal distress
Coughing or wheezing
What are the goals of care for dysphagia?
Prevent aspiration
Meet nutritional needs: kilojoules and protein requirements
Prevent dehydration
Restore normal swallowing
What are strategies for swallowing with dysphagia?
Sit upright Tilt head forward and tuck in chin Take small bites Place food on affected side Correct consistency Sweep mouth for pocketing Smaller, more frequent meals
What are the pharmacological strategies for restoring circulation after a stroke?
Anticoagulant therapy: warfarin, heparin, enoxaparin
Tissue plasminogen activator: within 3 hours of stroke, closely monitor for signs of haemorrhage or reperfusion injury
What is central post stroke pain?
CNS changes
Ipsilateral mostly
Continuous burning, pain, coldness, numbness, tingling, aching, throbbing, pinching, tearing
What is shoulder-hand syndrome?
Pain and oedema in hand, arm and shoulder from improper positioning, lack of ROM and immobility
What are the modifiable risk factors for a stroke?
HTN AF Smoking Hyperlipidaemia NIDDUM
What are the non-modifiable risk factors for a stroke?
Age
Gender
Previous stroke
Family history
