Neurology Flashcards
What are some causes of Neurological Deterioration?
- Alcohol
- Epilepsy
- Insulin
- Opiates
- Uraemia
- Tumour
- Injury
- Psychiatric
- Stroke
- Sepsis
(AEIOU TIPSS)
What is Increased intra-cranial pressure (ICP)?
Occurs when there is an imbalance inside the cranium, following brain injury or other medical conditions that cause an increase in pressure inside the skull.
What are the main elements generating ICP?
Brain tissue, blood volume and cerebrospinal fluid (CSF)
What is the patho of raised ICP?
A rise in ICP greater than cerebral perfusion pressure, (CPP), results in reduced blood flow to the brain as vessels are squashed from the pressure
Reduced blood flow = reduced oxygen and glucose delivery which results cerebral ischaemia.
What is the Monro-Kellie Hypothesis?
States that the sum of volumes of brain, cerebrospinal fluid (CSF) and intracerebral blood is constant
An increase in one should cause a reciprocal decrease in either one or both remaining two
What is Cushings Triad?
- Rise in ICP greater than CPP causes reduced blood flow to the brain. Reduced blood flow means less O2/glucose delivery to tissue causing cerebral ischaemia.
- Cerebral ischaemia stimulates a sympathetic response (adrenaline release to increase BP & HR) in order to increase blood flow and therefore O2 delivery
- Parasympathetic response initiated by increase BP is detected by baroreceptors. This results in an attempt to reduce BP by decreeasing HR
- Ongoing increased BP causes further rise in ICP and further restriction of blood flow. A switch of aerobic cellular respiration to anaerobic respiration results in decreased ATP production for cellular function (cerebral ischaemia)
- Breakdown of Na+/K+ pump causes water to enter the cell, resulting in cell death. As cerebral oedema worsens, the brainstem is compressed causing irregular respirations before death is imminent
What are the early signs of raised ICP?
Confusion
Drowsiness
Headache
Forgetfulness
Limb weakness
Nausea
Photophobia
Diplopia
Oval pupils (from round)
Impaired extra-ocular movement
What are the late signs of raised ICP?
Projectile vomiting
Seizures
Fixed and dilated pupil/s
Loss of gag reflex
Abnormal flexion/extension of upper and lower limbs
Hypertension (widening pulse pressure)
Bradycardia
Irregular respiratory pattern
How would someone’s LOC be with raised ICP?
Drowsiness
Lethargy
Dizziness
How would someone’s speech be with raised ICP?
Slurred (dysarthria)
Delayed
Word finding difficulty (expressive/receptive dysphasia)
No speech (aphasia)
How would someone’s motor strength be with raised ICP?
Mild/mod/severe weakness
Hemiplegia (one sided arm/leg/face weakness)
Sensation changes
Swallowing difficulties (dysphagia)
Uncoordinated
How would someone’s behaviour be with raised ICP?
Disinhibition
Personality change
Emotional
How would someone’s pupils be with raised ICP?
Unequal
Sluggish
Oval
Pinpoint
How would someone’s cognition be with raised ICP?
Poor memory
Inability to sequence
Change in comprehension
Confusion
What are the two priority assessments you would preform to assess neurological function?
AVPU
GCS
What does the brain need to function?
Oxygen and glucose
- when body is resting brain uses 20-25% of oxygen & glucose
Blood flow
- interruption causes irreversible damage within 3-8 minutes
Electrical conduction
- relay and process information
What is autoregulation?
A way of maintaining brain blood flow despite changes in cerebral perfusion pressure (the pressure required to deliver adequate oxygen and glucose)
Once cerebral perfusion pressure (CPP) is outside the range of 60-160mmHg, autoregulation is lost
If autoregulation is lost, the brain relies on mean arterial pressure (MAP) to maintain it’s blood supply
This means that if there is injury to the brain and a patient’s blood pressure is too low, there is not enough pressure to drive the blood around the brain
↓ oxygen ↓ glucose = brain tissue hypoxia and death
What are other neurological assessments?
Nervous system assessment
-Cranial nerves (CNI – XII)
-Spinal nerves (C1-8, T1-12, L1-5, S1-5, Co1)
–Reflexes
–Sensation
–Strength
Coordination and balance
Gait
Mini mental state examination (MMSE)
Speech and language
What are some diagnostic tests include?
Computerised tomography (CT)
Magnetic resonance imaging (MRI)
Carotid ultrasound/Doppler (measures cerebral blood flow)
EEG – electroencephalograms (electrical activity in brain)
Cerebral angiography: identify responsible blood vessel
Lumbar puncture for CSF analysis (can also be sampled
from ventricles)
Pharmacotherapy
Antiemetics
May provide nausea relief
Antipyretics
Reduce metabolic activity
Diuretics
Control fluid balance
Corticosteroids
Reduce cerebral oedema
Antiepileptics
Control of neurotransmitters
Thrombolytics
Fast dissolution of blood clots
Antiplatelets
Prevents platelets from sticking together and clumping
Analgesics
Reduce SNS activity and reduce ICP
Skeletal muscle relaxants
Ease contractures
Anti-parkinson
Increase dopamine/reduce acetylcholine activity to improve motor coordination
Faecal Softeners
Prevent straining and increasing ICP
Antibiotics
Reduce systemic inflammation and cerebral oedema
Antiarrhythmics
Improve cardiac output and cerebral perfusion
Antihypertensives
Prevent secondary cerebral ischaemia through raised ICP
