Neuro Flashcards
Explain the anterior and posterior circulation of the Circle of Willis
Anterior - branches of internal carotid
- Anterior Choroidal artery
- Anterior/Middle cerebral artery
Posterior - branches of vertebrobasilar arteries
- Posterior Cerebral artery
- Basilar artery
- Superior cerebellar artery
- Anterior/Posterior inferior cerebellar artery
What is Broca’s area, and what does an injury of it cause?
Located in the frontal lobe of person’s dominant side (left in right handed people) and influences motor production of speech.
Causes expressive aphasia - Patients can understand speech but can’t produce it themselves
What is Wernickes area and what does injury of it cause
Located in parietal and temporal lobe of person’s dominant side (left in right handed people) , influences understanding of speech and using correct words to express thoughts
Causes receptive aphasia - Patients can produce speech but don’t understand the meaning of spoken words
What are Wernickes and Brocas areas supplied by?
Middle Cerebral Artery
What is a watershed area?
Areas furthest from blood supply, most susceptible to infarction
Define ischaemic stroke
Reduced cerebral blood flow due to arterial occlusion or stenosis. Account for 85% of all strokes.
Consists of rapidly developing signs of cerebral dysfunction, lasting more than 24 hours, with no apparent cause.
Causes of ischaemic stroke
Disruption of blood supply secondary to:
- Thrombus formation/ embolus
- Atherosclerosis
- Shock
- Vasculitis
- Hypercoagulability (thrombophilia)
Risk factors for stroke (9)
- Male
- Old (>55)
- Black or Asian
- History of Ischaemic stroke or TIA
- Atrial fibrillation
- Sickle cell disease
- Combined contraceptive pill
- Carotid artery stenosis
- Smoking, obesity, HTN, T2DM
Define hemiparesis
Weakness or paralysis on one side of the body
Manifestations of an Anterior Cerebral Artery ischaemic stroke
- Contralateral hemiparesis and sensory loss, affecting lower limbs>upper limbs
Manifestations of middle cerebral artery stroke
- Contralateral hemiparesis and sensory loss affecting upper limbs>lower limbs.
- Aphasia if affecting Broca or Wernickes areas in dominant hemisphere
- Homonymous hemianopia (visual field defect in same side of both eyes)
Manifestations of Posterior Cerebral Artery stroke
- Contralateral homonymous hemianopia with macular sparing (preservation of central visual field)
- Contralateral loss of pain and temperature
Manifestations of Vertebrobasilar artery stroke
Cerebellar signs (intention tremor, nystagmus, hypotonia)
Reduced consciousness
Quadriplegia
Manifestations of Webers syndrome (midbrain infarct)
Oculomotor palsy and contralateral hemiplegia
Manifestations of Lateral medullary syndrome (posterior inferior cerebellar artery occlusion)
Ipsilateral facial loss of pain and temperature
Ipsilateral Horner’s syndrome: miosis, ptosis, anhidrosis
Ipsilateral cerebellar signs
Contralateral loss of pain and temperature
What is lacunar stroke?
Stroke affecting small branches of middle cerebral artery.
Causes one of the following:
Pure motor loss
pure sensory loss,
ataxic hemiparesis
What is pronator drift
Ask patient to raise arms. On the affected side, palm and arm will face inward and downwards. Suggests muscle weakness.
(Symptoms contralateral to affected brain side)
What assessment system is used in acute strokes
ROSIER (Recognition of Stroke In Emergency Room)
Uses symptoms as + points and mimics (syncope, seizure activity) as - points
Investigations on stroke presentation
- Assessment using ROSIER scale
(stroke possible if >0) - Non contrast CT head (rule out haemorrhagic stroke)
- CT Angiogram (identify occlusion - hypoattenuation of brain parenchyma, loss of matter differentiation)
How do strokes appear on CT
Ischaemic - Darkness of brain parenchyma
Haemorrhagic - Brightness surrounded by darkness (blood surrounded by oedema)
Management of ischaemic stroke
Once haemorrhagic ruled out:
- IV Alteplase if presents within 4.5 hours
- Mechanical thrombectomy if after 4.5 hours
Then: 300mg Oral aspirin daily for 2 weeks then clopidogrel lifelong daily
What are the driving rules in ischaemic stroke
Patients must not drive car for 1 month after TIA or stroke, or 1 year for HGV
What classification system is used in stroke?
Bamford classification - categorises stroke based on area of circulation affected.
- Total anterior circulation stroke - Anterior/middle cerebral artery (all 3 - Unilateral weakness of face,arm or leg, homonymous hemianopia, higher cerebral dysfunction)
- Partial anterior circulation stroke - only part of anterior circulation (2 out of 3 symptoms)
- Lacunar - Either: All sensory, all motor or ataxic hemiparesis
- Posterior circulation syndrome (1 of cranial nerve palsy, bilateral motor/sensory defecit, eye movement disorder, homonymous hemianopia)
Scoring system for risk of stroke after Atrial Fibrillation
CHA2DS2 VASc
Define TIA
Transient Ischaemic Attack. Acute neurological dysfunction that has a sudden onset and resolves in less than 24 hours.
NOT a stroke as involves ischaemia not infarction
Symptoms of TIA
- Contralateral numbness, face drooping, dysphasia, vision loss
- Amaurosis Fugax
Same as stroke but lasts less than 24 hours and no lasting effects
What acronym helps identify stroke in public
FAST
Face
Arms
Speech
Time
Define amaurosis fugax with pathophysiology and causes
Short lived blindness in one eye described as “curtain coming down over vision”. Due to temporary reduction in internal carotid or central retinal artery leading to ischaemia of the retina.
- Occurs in GCA, Stroke, AF
What risk score should be completed after TIA
ABCD2 - risk of stroke after TIA
Age >60
BP >140/90
Clinical features (unilateral weakness =2, just speech disturbance =1)
Duration >60mins =2, 10-59mins =1
> 6 predicts stroke, immediate referral
4 requires referral
Management of TIA
1st line - 300mg Aspirin daily for 2 weeks
- Clopidogrel daily long term
- Atorvastatin
ABCD2 score to assess stroke risk
What is it called when 2 TIAs happen in close proximity
Crescendo TIAs.
Requires urgent referral
What are the layers over the brain called
Meninges of the brain
- Dura mater
- Arachnoid
- Pia mater (innermost layer)
What are the types of haemorrhagic stroke
Extradural haemorrhage - bleeding above dura mater
Sudural haemorrhage - bleeding between dura and arachnoid
Subarachnoid haemorrhage - bleeding between arachnoid and pia mater
Intracerebral haemorrhage - Bleeding within cerebrum
Risk factors for haemorrhagic stroke (6)
Head injury
Hypertension
Aneurysms
Brain tumour
Connective tissue disorder
Family history
General symptoms of haemorrhagic stroke
Reduced GCS
Headache
Vomiting
Seizures
One sided arm/leg/face weakness/paralysis
Give the scoring system for unconsciousness
Glasgow Coma Scale - assessment of eye opening, verbal and motor response.
Minimum score 1 per category
Give the scoring system for consciousness
Glasgow Coma Scale - assessment of eye opening, verbal and motor response.
Eye out of 4
Verbal out of 5
Motor out of 6
Minimum score 1 per category
Glasgow coma scale scoring system in detail (not sure if need to know but probably helpful to have decent idea)
Eye opening
4 - Spontaneous
3 - To speech
2 - To pain
1 - None
Verbal response
5 - Orientated
4 - Confused conversation
3 - Inappropriate words
2 - Incomprehensible sounds
1 - None
Motor response
6 - Obeys command
5 - Localises to pain
4 - Withdraws to pain
3 - Abnormal flexion to pain
2 - Extension of upper and lower limbs to pain
1 - No response
Define Extradural haemorrhage with its main cause and epidemiology
Cranial bleeding above the dura mater.
Usually caused by trauma to pterion of skull, causing rupture of middle meningeal artery in temporo-parietal region. Can associate with temporal bone fracture.
Usually found in young adults
Why can extradural stroke present slowly at first before becoming more severe
If bleeding is slow, symptom onset is slower (lucid interval) before there is a sudden, rapid decline when intracranial pressure increases enough to compress brain
Describe Non contrast CT appearance in Extradural haemorrhage (3)
- Biconvex, hyperdense haematoma
- Blood doesnt cross suture lines
- Shows midline shift (increased pressure can cause cause brain shifting/herniation)
What are the main 2 herniation complications of haemorrhagic stroke
Supratentorial herniation (cerebrum against skull, compressing arteries and causing ischaemic stroke)
Infratentorial herniation (Cerebellum pushed against brainstem, compressing area that controls consciousness, respiration, heart rate)
What is Cushing’s triad and how is it treated
Body’s response to increased intracranial pressure, signifies severe lack of oxygen in brain tissue
- Bradycardia
- Irregular respirations
- Widened pulse pressures (increased systolic, decreased diastolic)
Treated with IV mannitol to reduce ICP
Define Subdural haemorrhage with main cause and epidemiology
Bleeding below dura mater, caused by bridging vein rupture.
Usually occur in elderly/alcoholic patients but can occur in babies (shaken baby syndrome)
Define acute acute on chronic and chronic subdural haemorrhage
Acute - symptoms <2 days since injury
Acute on chronic - 3-14 days
Chronic - >15 days
Causes of bridging vein rupture
- Brain atrophy; with age. Stretches bridging veins, meaning they stretch over gaps unsupported.
- Alcohol abuse: Causes walls of vein to thin
- Trauma
- Falls
- Shaken baby syndrome
- Acceleration/deceleration injury
Non contrast CT appearance of Subdural haemorrhage
- Bleeding between the dura mater and arachnoid
- Follows contours of brain and crosses suture lines, forming a crescent shape
- Acute (Hyperdense mass)
- Chronic (Hypodense mass)
- Acute on chronic (both)
What GCS score requires intubation
8 or below
Specific surgical management used in subdural haemorrhage
Burrhole washout if haemorrhage small
Craniotomy if large haemorrhage
Define subarachnoid haemorrhage with main cause
Bleeding below the arachnoid layer, where CSF is located.
Main cause is a ruptured saccular (or Berry) aneurysm, with majority located between anterior communicating artery and anterior cerebral artery
Other causes of subarachnoid haemorrhage
- Trauma
- AV malformations
- Vasculitis
- Bleeding disorders
- Brain tumour bleeding
Risk factors for subarachnoid haemorrhage (7)
PKD (Associated with berry aneurysm)
Connective tissue disorders (Ehlers-Danlos, Marfans)
Family history
Increasing age
HTN
Smoking
Alcohol
Pathophysiology of subarachnoid haemorrhage
- Berry aneurysm rupture causes bleeding into subarachnoid space, increasing ICP, which puts pressure on nearby tissue and blood vessels, causing tissue infarction
- Blood vessels bathing in pool of blood vasospasm. If this affects circle of Willis, further ischaemic damage to brain
- Blood irritates meninges, causing inflammation/scarring of surrounding tissue (meningism symptoms). Scar tissue obstructs normal outflow of CSF, causing buildup known as hydrocephalus
Typical presentation of subarachnoid haemorrhage
Sudden onset occipital “thunderclap” headache, following strenuous activity, with associated neck stiffness and photophobia. Smaller, “Sentinel” headache may have preceded thunderclap
Black, female, 45-70
Signs/symptoms of subarachnoid haemorrhage
- Thunderclap headache
- Meningism (Headache, photophobia + neck stiffness)
- Fixed dilated pupil (third nerve palsy - especially in posterior communicating artery rupture)
- 6th nerve palsy
- Kernigs and Brudzinskis due to meningism also
Nausea/vomiting, weakness, confusion, coma, reduced consciousness, speech reduction
Investigations in subarachnoid haemorrhage
Urgent non contrast CT head (blood in subarachnoid space/basal cisterns)
CT angiography to locate bleed source
ECG to detect arrhythmia/abnormality
If CT non conclusive,
- Lumbar puncture (RBCs in CSF and Xanthochromia) 12 hours after onset.
Define Kernigs and Brudzinskis signs
Kernig - Inability to straighten bent leg without pain when hip flexed to 90 degrees
Brudzinski - Passive flexion of neck in supine patient elicits hip and knee flexion
Suggest meningitis/meningism
CT Appearance in subarachnoid haemorrhage
- Blood in subarachnoid space (hyperdense)
- Star shaped lesion (blood filling in gyro pattern)
Management of Subarachnoid haemorrhage
Surgical 1st/GOLD
- Endovascular coiling (clipping also possible but more complications)
Nimodipine to prevent vasopasms
IV Mannitol to reduce ICP
Sodium valproate for seizures
Define intracerebral haemorrhage with causes
Bleeding directly into brain tissue. Presents the same as ischaemic stroke.
Can occur spontaneously, due to ischaemic infarct, tumour or aneurysm rupture
Treatment options for intracerebral haemorrhage
Surgical:
- Craniotomy (if close to surface)
- Stereotactic aspiration (aspirate blood, relieve ICP)
IV Mannitol for ICP
Define meningitis
Inflammation of the meninges (specifically leptomeninges - pia and arachnoid). Can be due to viral, bacterial or fungal cause.
Notifiable disease
Viral causes of meningitis
More common but less severe
- Coxsackie virus
- HSV (Herpes simplex virus)
- Varicella Zoster virus
- Mumps
Bacterial causes of meningitis
Most common - S. pneumoniae and N. meningitidis
Children - ^ and H influenzae
Elderly and pregnant - Listeria Monocytogenes (pregnant avoid cheese)
Newborns - ^ and Group B strep
Why is group B strep common in neonatal meningitis
Because group B strep lives harmlessly in the maternal vagina
How do N meningitidis, S pneumoniae, Group B strep and Listeria monocytogenes present on gram film
- N meningitidis - Gram negative diplococci (Only one that causes non blanching rash!)
- S pneumoniae/Group B strep - Gram positive cocci in chains
- Listeria monocytogenes - Gram positive bacillus
Pathophysiology of meningitis
Infection of leptomeninges and CSF. Infection route via direct spread or haematogenous spread. WBC. Causes white blood cell infiltration of CSF (>5 diagnostic). Bacterial and viral cause increase in protein. Bacterial causes decrease in glucose and forms pus.
Fungal infection can cause chronic meningitis.
Signs/symptoms of meningitis
Signs
- Neck stiffness, headache, photophobia (avoids light)
- Phonophobia (avoid sound)
- Papilloedema (optic disk swelling)
- Kernig sign
- Brudzinski sign
- Non blanching rash (N meningitidis only)
Pyrexia, reduced GCS
Investigations in meningitis
Blood culture 1st line - Bacterial or negative for viral
Lumbar puncture GOLD
Bacterial
- Cloudy/yellow
- Protein high
- Glucose low (<50% normal)
- WCC high (Neutrophil)
Viral
- Clear appearance
- Protein small raise/normal
- Glucose normal (>60% normal)
- WCC high (lymphocytes)
(Gram stain identifies bacteria and CSF PCR identifies viruses)
Fungal appearance of CSF in meningitis
Cloudy and fibrous
Protein high
Glucose low
WCC high - Lymphocytes!
Management of bacterial meningitis
Primary care: Immediate IV or IM benzylpenicillin (if suspected meningococcal) and hospital referral
Hospital
- Dexamethasone (steroid)
- Cefotaxime or Ceftriaxone IV
- Give Amoxicillin if under 3 months or over 50 to cover listeria
- Contact tracing and single dose oral ciprofloxacin for contacts
Management of viral meningitis
Supportive (Analgesia, hydration etc)
Aciclovir
Complications of meningitis
Hearing loss
Seizures
Cognitive impairment
Hydrocephalus
Sepsis
Define Encephalitis
Inflammation of brain parenchyma, mostly frontal and temporal lobes.
Usually viral cause but can be autoimmune
Causes and epidemiology of encephalitis
Usually in elderly or babies, or immunosuppressed
Infective
- Infective: Herpes simplex virus (HSV-1 - Cold sores, HSV-2 genital herpes)
- N meningitidis
- TB
Non infective: Autoimmunity
Signs/symptoms of encephalitis
Triad:
- Fever, headache, altered mental status
Meningism:
- Stiff neck, headache, photophobia
Also presents with neurological deficit
- Aphasia/Dysphasia
- Hemiparesis
Investigations in encephalitis
FBC - high WCCs (infection)
ESR/CRP raised
Lumbar puncture - high lymphocytes
Throat swab for viral culture
CT/MRI head GOLD (Areas of inflammation in brain)
Management of encephalitis
Urgent hospital admission and aciclovir
(Ganciclovir if cytomegalovirus)
Upper motor neurone lesion signs vs lower motor neurone lesion signs
Type of paralysis
-reflexia
Fasciculations
Babinski sign
Voluntary movement
Muscle tone and power
UMN
Spastic paralysis
Hyperreflexia
No fasciculations
Babinski positive
Voluntary movement slowed
Muscle tone and power kept
LMN
Flaccid paralysis
Hyporeflexia
Fasciculations
Babinski negative
Voluntary movement gone
Muscle tone and power lost
(babinski - toes curl up when bottom of foot is stroked
fasiculations - brief spontaneous contractions under skin)
Define Multiple sclerosis
Type 4 hypersensitivity reaction in which there is autoimmune attack against oligodendrocytes (which create myelin) in the CNS (Brain/Spinal cord). Causes plaques of demyelination.
Risk factors for multiple sclerosis (6)
Female
20-40
Vitamin D deficiency
Family history (HLA-DR2)
Autoimmunity
EBV infection
Pathophysiology of multiple sclerosis
T cells cross Blood Brain Barrier and launch immune response against oligodendrocytes. Eventually, plaques form.
Lesions vary, meaning plaques are “disseminated in space and time” - affect different areas of CNS at different times/ events.
Disease progression types in MS
- Relapsing remitting (most common) - Episodic flare ups without full recovery in between, meaning flares worsen over time. (Most common and often progress to secondary progressive)
- Secondary progressive - Symptoms start getting worse without remission
- Primary progressive - Symptoms worsen without remission (/)
- Progressive relapsing - Constant attack with superimposed flare ups
What is Uhtoff’s phenomenon and why does it occur in MS
Symptoms worsen with heat (e.g. hot bath) or exercise.
New myelin is inefficient, and doesn’t tolerate temperature rise effectively.
What triad is associated with MS
Charcot’s neurological triad
- Nystagmus (involuntary side-to-side/up-down rapid eye movements)
- Dysarthria (slowed, slurred speech)
- Intention tremor
Signs and symptoms of MS
- Optic neuritis usually first (Loss of vision, eye pain, pale optic disk, double vision)
- Internuclear ophthalmoplegia (eye muscle paralysis which impairs lateral gaze)
- Lhermitte’s sign - Electric shock sensation when flexing neck
- UPPER motor neurone signs
Bowel, bladder, erectile dysfunction
Ataxia
Sensation loss
(Uhthoff’s and Charcot’s neurological triad already mentioned)
What criteria is used in diagnosis of MS
McDonald criteria (think McDonald’s M!)
- 2 or more relapses with evidence of 2 or more lesions, or one lesion with reasonable history of relapse