Neuro Flashcards
Define conciousness
Consciousness: Wakefulness and awareness
Assessment relies on physical responses at the bedside
Define minimally conscious state
Legal aspects?
-May move finger
-Continual (>4weeks) versus permanent (years)
-Could get better
Official solicitor protects people with minimal consciousness
Define persistent vegetative state
Some weeks/months after initial injury Unawareness of self Awake but not aware May open eyes, can breathe and heart will pump Will not respond to commands, loved ones Permanent>6 months
Define coma
Not awake and not aware
Eyes are closed
No response to environment, voices or pain
Brainstem involvement in consciousness?
- Survival functions
- Contains ascending reticular activating system (RAS)
- Determines how awake people are, necessary for consciousness
Define locked in syndrome
Patient fully awake and alert but cannot move or speak
Can mimic loss of consciousness
Ocular muscle usually spared (communicate by blinking)
After basilar artery occlusion/pontine injury/ALS/MS
Name 2 confounders of the Glasgow Coma Scale
Spinal cord injury
Deafness
When are pupils small and reactive?
Opioid use
When are pupils small and unreactive?
Pontine haemorrhage
When are pupils unreactive
Atropine
When are pupils unreactive and dilated?
Brainstem herniation
Seizures
Definition of a stroke
Sudden onset loss of CNS functioning lasting >24 hrs due to a vascular cause
Cause of 1/10 deaths in UK
Causes of stroke
- 85% ischaemic
* 15% haemorrhagic
Causes of ischaemic stroke (12)
- Atherothrombosis: 50%, large vessel atheroma causing local narrowing and distal thromboembolism, usually aortic arch, carotid bifurcation, vertebral artery
- Small vessel disease: 20-25%, lipohyalinosis and fibrinoid degeneration of small intracranial vessels, hypertension. Causes small lacunar infarcts of internal capsule
- Cardioembolic: 20-25%, emboli secondary to arrhythmia (AF), valvular disease (replacements, vegetations), poor LV function, post MI. Usually left side of heart-> intracranial vessels unless septal defect, then from DVTs
- Arterial dissection (may present with neck pain and Horner’s syndrome)
- Hypotension-> watershed infarct after cardiac arrest
- Vasculitis
- Hypercoagulability: Antiphospholipid syndrome, malignancy
- Genetic disorders: mitochondrial, homocysteinuria, CT disorders, sickle cell
- Illicit drugs (cocaine)
- Secondary to CNS infection (syphilis, HIV)
- Trauma to neck vessels
- Secondary to venous sinus thrombosis
4 types of intracranial haemorrhage
- Intracerebral
- Subarachnoid
- Subdural
- Extradural
Causes of intracerebral haemorrhage
- Hypertension
- Amyloid angiopathy
- Trauma
- Bleeding disorders
- Illicit drugs (cocaine, amphetamines)
- Vascular malformations
Definition of SAH
Subarachnoid haemorrhage
Blood between arachnoid and pia mater
Most often occurs after trauma
If not trauma, usually a spontaneous haemorrhage due to a vascular anomaly
Symptoms of SAH
- Vary from delayed presentation of low-grade headache to coma or sudden death
- Headache (sudden, thunder clap, worst headache ever, occipital
- Nausea and vomiting
- Meningism (neck stiffness, photophobia)
- Seizure and transient loss of consciousness
Management of SAH
- Assess GCS and look for focal deficits
- Plain CT scan (93% sensitivity 24 hrs, 50% at 1 week)
- If –ve but high clinical suspicion-> LP 12 hrs after onset of symptoms (4 bottles for red cell count, glucose, spectrophotometry and cell counts again)
- CT angiogram/catheter angiography to find vascular anomaly
Treatment of SAH
- Resuscitation, airway protection if GCS<8
- Analgesia and anti-emetics
- IV hydration to maintain cerebral blood flow and avoid ischaemia
- NIMODIPINE 50mg 4hrly for 21 days from onset of symptoms
- BP control (hypertension-> rebleed, hypotension-> ischaemia)
- VTE prophylaxis
- Neuro obs
- Hydrocephalus treatment (shunt?, head up)
- Aneurysm? Embolisation via coiling or craniotomy and clipping
3 main complications of SAH
- Vasospasm (leads to delayed ischaemic neurological deifcits)
- Hydropcephalus (communicating/obstructive, may require LP or shunt)
- Hyponatraemia (cerebral salt wasting and SIADH, risk of seizures)
Factors associated with aneurysm rupture
- Previous rupture of same aneurysm (30% rebleed within 1 month)
- Previous rupture of a contemporaneous aneurysm
- Size
- Posterior circulation
- Smoking
- Evidence of growth/compression (IIIrd nerve palsy)
Describe subdural haemorrhage
- Collection of blood in the potential space between dura and arachnoid mater
- Seen in extremes of age, esp after trauma (eg falls in the elderly)
- May present with cerebral contusions and depressed GCS
- Due to stretching and tearing of the bridging veins as they cross to drain into a dural sinus when shearing force is applied
- Crescent shaped
Describe extradural haemorrhage
- Collection of blood between the inner surface of the skull and the outer layer of dura
- Commonly associated with trauma and associated skull fracture, seen in the young. On-going severe headache, gradually lose consciousness over next few hours.
- Usually the bleeding is associated with a torn middle meningeal artery
- Lens/lemon shaped
- Can cause midline shift/herniation
