Neurology Flashcards
What are the 3 layers of the meninges?
Dura - outer
Arachnoid- keeps CSF in contact with brain
Pia- on brain surface, present between vessels and neurons
Where does the circle of Willis lie?
Subarachnoid - between arachnoid and pia
What myelinates axons in the brain?
Oligodendrocytes
What myelinates axons in the rest of the body?
Schwann cells
What are 3 functions of the frontal lobe?
Voluntary movement on opposite side of body
Dominant hemisphere controls speech and writing (right handed = left dominant)
Reasoning
Memory
Intellectual functioning
What is the primary function of the parietal lobe?
Receives and interprets sensations (pain, touch, size, shape and proprioception)
What is the primary function of the temporal lobe?
Understand spoken word (wernickes) and sounds
What are the 2 primary functions of the occipital lobe?
Understanding visual images
Understanding meaning of written words
Where is CSF produced?
Ependymal cells in choroid plexuses of lateral ventricles
Where is CSF absorbed?
Arachnoid granulations in superior sagittal sinus
Where do sympathetic nerves arise from?
Thoracic and lumbar regions of spinal cord
What receptors are present at Presynaptic sympathetic neurones?
Nicotinic
What receptors are present at postsynaptic sympathetic neurones?
Adriinergic receptors
What neurotransmitter is used at presynaptic sympathetic neurones?
Acetylcholine
What neurotransmitter is used at postsynaptic sympathetic neurones?
Noradrenaline
What neurotransmitter is used at presynaptic parasympathetic neurones?
Acetylcholine
What neurotransmitter is used at postsynaptic parasympathetic neurones?
Acetylcholine
What receptors are present at presynaptic sympathetic neurones?
Nicotinic
What receptors are present at postsynaptic parasympathetic neurones?
Muscarinic
What are 3 functions of the sympathetic system?
Inc HR
Increases force of contraction
Vasoconstriction
BronchoDILATION
Reduces gastric motility
Male ejaculation
What are 3 functions of the parasympathetic nervous system?
Decreases heart rate
Decrease force of contraction
Vasodilation
BronchoCONSTRICTION
Increases gastric motility
INCREASED gastric secretions
Male erection
Define dermatome
Area of skin supplied by a single spinal nerve
Define myotome
Volume of muscle supplied by a single spinal nerve
Define transient ischaemic attack (TIA)
Brief episode (5-15 mins) of neurological dysfunction due to ischaemia without infarction
What are the risk factors of TIA?
Age
Smoking
HTN
Past TIA
Heart disease
AF
What are 3 causes of TIA?
Atherthromboembolism from carotid (MC)
Small vessel occlusion
Valve disease
Hyperviscosity
What 2 regions of circulation can be affected by TIA?
90%= anterior circulation (carotid artery)
10% = posterior circulation (vestibulobasilar artery)
What are the symptoms of an anterior/carotid TIA?
Weak/ numb contralateral leg
Amaurosis fugax
Dysphasia
Hemiparesis (one sided weakness)
Define amourosis fugax
Sudden transient loss of vision in one eye
“Curtain comes down vertically into one field of vision”
What causes amaurosis fugax?
Temporary reduction in blood flow to the retinal,ciliary or ophthalmic artery causing temporary retinal hypoxia
What is amaurosis fugax a sign of?
Imminent stroke
What are the symptoms of a posterior TIA?
Diplopia (double vision)
Vertigo
Vomiting
Choking
Ataxia (no control of body movement)
Transient global amnesia
Can be unconscious
What is the differential diagnosis of TIA?
Stroke
- impossible to differentiate until after
- TIA usually resolves, stroke often doesn’t
- stroke infarct
How is TIA diagnosed?
Usually clinical
Diffusion weighted MRI (1st line)
Carotid artery doppler ultrasound to find issues
Bloods: polycythaemia, vasculitis ect
How is stroke risk predicted after TIA?
ABCD2
What ABCD2 score strongly predicts a stroke?
6<
Greater than 4 should be seen within 24 hrs
How is TIA treated acutely?
Immediate 300mg aspirin
AF = anticoag
How is TIA treated long term?
Aspirin + Clopidogrel (P2Y12 inhibitor) 75mg
Long term statin
Control CV factors
What is an example of a statin?
Simvastatin
What are the 2 types of stroke?
Haemorrhagic
Ischaemic
Define stroke
Rapid neurological disturbance lasting >24 hours caused by infarction
Who is most commonly affected by strokes?
BAME
Men
Increases with age
What type are most strokes?
Ischemic
Define ischaemic stroke
Arterial embolism occludes a vessel resulting in infarction
Define haemorrhagic stroke
Rupture of blood vessel leading to infarction
What are 3 risk factors of strokes?
Increased age
HTN
Smoking
Past TIA
DM
Heart disease
What are 3 causes of ischaemic stroke?
Thromboembolism
Cardioembolism
Hyperviscosity
Hypoperfusion (blood loss)
What are the symptoms of a stroke in the ACA region?
Leg weakness
Gait apraxia (loss of function in lower limbs)
Incontinence
Drowsiness
What are the symptoms of a stroke in the MCA region?
Contralateral arm and leg weakness+ sensory loss
Aphasia/ Dysphasia
Facial droop
Homonymous hemianopia
What is the MC stroke region presentation?
MCA
What are the symptoms of a stroke in the PCA territory?
Contralateral homonymous hemianopia (visual field loss in same halves of both eyes)
Cortical blindness
Visual agnosia
Prosopagnosia (cant see faces)
Unilateral headache
What are the symptoms of a stroke in the posterior (vestibulobasilar) region?
Very catastrophic
Facial paralysis
Quadriplegia
Altered consciousness
What are 2 differential diagnoses of stroke?
Hypoglycaemia
Intracranial lesion
Syncope
Define lacunar stroke
Infarct of small arteries supplying the midbrain (internal capsule, basal ganglia ect)
What are the symptoms of a lacunar stroke?
Pure sensory loss
Ataxic hemiparesis
Unilateral weakness
How is stroke diagnosed?
- Immediate non contrast CT (identifies haemorrhagic)
GS: MRI
ECG for AF or MI
Bloods: thrombocytopenia ect
How is stroke classified?
Bamford classification
How is ischemic stroke treated?
Immediate 300mg aspirin
Thrombolysis with altepase (within 4.5 hours)
After:
Aspirin for 2 weeks
Clopidogrel
How is haemmoragic stroke treated?
Neurosurgery immediately
Stop anticoags
Mannitol (diuretic) to decrease pressure
What is a specific sign of stroke?
Pronator drift
- arm on affected side will pronate with palm down when patient asked to lift arms to ceiling
What are 4 types of haemmorhage?
Intracerebral
Subarachnoid
Extradural
Subdural
Define subarachnoid haemorrhage (SAH)
Spontaneous bleeding into subarachnoid space (between arachnoid and pia)
What is the MC cause of SAH rupture?
Berry aneurysm
Also
Trauma
AV malformation
Idiopathic
What age is commonly affected by SAH?
35-65
Define berry aneurysm
Rupture at the junction of circle of Willis
What is the MC site of a berry aneurysm?
Anterior communicating/ ACA junction
What are the risk factors of SAH?
HTN
FHx
Polycystic kidneys
Connective tissue disorders
Coarctation of aorta
What is the mortality rate of SAH?
50% <
The rest usually left with significant disability
What are the symptoms of SAH?
Sudden onset of severe occipital headache ‘thunderclap”
May have sentinel headache (early sign before)
Meningitis signs
Decreased consciousness
Fixed dilated pupils
What are 2 differential diagnoses of SAH?
Migraine
Meningitis
Intracerebral bleeds
How is SAH diagnosed?
Head NC-CT (GS)- star shaped
Lumbar puncture if CT doesn’t confirm
- xanthochromia confirms
What does a star shape in the middle of the brain on CT indicate?
SAH
How is SAH treated?
Refer to neurosurgeon - endovascular coiling
Nimodipine (CCB)
What are 2 complications of SAH?
Re bleeding
Hydrocephalus
Cerebral ischaemia
Define Subdural haemorrhage (SDH)
Accumulation of blood between the arachnoid and dura mater following the rupture of a bridging vein between cortex and venous sinus
What are the risk factors of SDH?
Small brain: babies, alcoholics, dementia
Trauma- can be long ago or very minor
Anticoag
What are 3 causes of SDH?
Deceleration trauma
Shaken babies/abuse
Brain atrophy
Outline the pathophysiology of SDH
Bleeding from bridging veins into SD space -> clot -> later clot autolyses (draws water and expands) -> increase in ICP -> shifting of midline structures -> hernia and death
What are the symptoms of SDH?
Long interval between injury and symptoms and gradual onset
Decreased/ fluctuating consciousness
Drowsiness
Behaviour change
Signs of increased ICP: Cushing triad
How is SDH diagnosed?
NC-CT head - crescent shaped/banana
Acute = hyperdense, chronic = hypodense
Midline shift
What is banana shape on CT indicative of?
SDH
suBdural = Banana
What is Cushings triad? (signs of ICP)
Bradycardia
Irregular breathing
hypertension
How is SDH treated?
Surgery: burr hole and craniotomy
IV mannitol to decrease ICP
Define extradural haemorrhage (EDH)
Collection of blood between the dura mater and bone usually due to head injury
What is the MC cause of EDH?
Rupture of middle meningeal artery after fracture of the temporal bone
What are the risk factors of EDH?
Young adult - decrease risk when age increases
Trauma
Why is EDH uncommon in older people?
Dura more adhered to skull
What are the symptoms of EDH?
Head injury -> initial loss of consciousness and drowsiness -> lucid interval -> rapid deterioration
“I feel fine”
Late onset = severe headache, nausea, vomiting, decreased GCS, death (resp arrest) ect
What are the differential diagnoses of EDH?
Epilepsy
CO poisoning
Meningitis
How is EDH diagnosed?
NC-CT head: shows lemon shape
Confined to cranial sutures
May show skull fracture
Midline shift
What is a lemon shape on CT head indicative of?
EDH
How is EDH treated?
Urgent surgery to evacuate clot and ligate vessel
ABCDE
IV mannitol
What causes Intracerebral haemorrhage?
Spontaneous due to ischemic infarction or aneurysm rupture
What are the signs of Intracerebral haemorrhage on CT?
Acute/fresh bleed is hyperdense on CT (bright white)
Define meningitis
Inflammation of the meninges
What is the MC cause of meningitis in pregnancy?
Listeria monocytogenes
What are 2 causes of meningitis in neonates?
Group B haemolytic strep (colonises vagina)
- S.agalactiae
E. Coli
What are 3 causes of meningitis in children?
N. Meningitidis
Strep. Pneumoniae
Haemophilius influenzae
What are 3 causes of meningitis in elderly people/immunocompromised?
Cytomegalovirus
Cryptococcus neoformans
TB
HIV
HSV
What is fungal cause of meningitis?
Cryptococcus neoformans
What type of bacteria is n. Meningitidis?
Gram negative diplodoccus
What is the MC cause of meningitis?
Viral (Enteroviruses) eg
HSV2
Varicella
Measles
What is the sign of N. Meningitidis?
Non blanching purpuric rash
What is the appearance of S. pneumoniae?
Gram positive diplococcus in chains
What vaccine is available against N.Meningitidis?
Men B+C
Men ACWY
What vaccine is available against s. Pneumoniae?
PCV
What are the risk factors of meningitis?
Intrathecal drug administration (spinal canal)
Age extremes
Pregnancy
Crowding
Endocarditis
What are the general symptoms of meningitis?
Headache
Neck stiffness
Fever
What are the symptoms of bacterial meningitis?
Sudden onset
Triad of normal symptoms
Papillodema
Non blanching purpuric rash
Altered mental state
Positive signs
Nerve palsies (III)
What are the 2 signs of meningitis?
Kernig’s sign
Brudzinski’s sign
What is Kernig’s sign?
Can’t extend knee without pain when hip is flexed
What is Brudzinski’s sign?
Knees and hips automatically flex when neck is flexed
What are the symptoms of viral meningitis?
Benign and self limiting
Headache can last for a few months
How is meningitis diagnosed?
Blood tests before LP
LP and CSF analysis
What is present in bacterial meningitis CSF?
Cloudy yellow colour
Neutrophilia and polymorphs
Low glucose
Increased opening pressure
What are the CSF findings in viral meningitis?
Clear CSF
Lymphocytes
Normal glucose
Normal opening pressure
What are the CSF findings of TB meningitis?
Ziehl Neelson stain
Low glucose
High opening pressure
How is bacterial meningitis treated in the community?
Immediate IV or IM benzylpenicillin
How is bacterial meningitis treated in hospital?
IV cefotaxime or ceftriaxone
+ amoxicillin for neonates and elderly
+ vancomycin for travellers
Also dexamethasone to reduce cerebral oedema
What is given to those in contact with people with meningitis?
Ciprofloxacin (all ages and pregnant)
Or
Rifampicin (NOT FOR PREGNANCY)
How is viral meningitis treated?
Usually fine
Acyclovir for HSV
What are 2 differential diagnoses of meningitis?
Subarachnoid haemorrhage
Migraine
What are 3 complications of meningitis?
Hearing loss
DIC (septicaemia)
Waterhouse freidrechsen syndrome (adrenal haemorrhage -> adrenal insufficiency)
Define encephalitis
Infection and inflammation of the brain parenchyma
What is the MC cause of encephalitis/
HSV-1
Also: varicella, HIV, EBV, toxioplasmosis (cats)
What are the risk factors of encephalitis?
Extremes of age
Immunocompromised
What are the symptoms of encephalitis?
Triad: fever, headache, altered mental state
Features of viral infection
Seizures
Whole brain affected = problems of consciousness
How is encephalitis diagnosed?
MRI
CSF shows elevated lymphocytes
EEG shows sharp and slow waves
What lobe is MC affected by encephalitis?
Temporal
How is encephalitis treated?
IV aciclovir
Mostly supportive
If seizures give primidone
What are the causes of seizures?
VITAMIN DE
Vascular
Infection
Trauma
Autoimmune
Metabolic
Idiopathic (EPILEPSY)
Neoplasms
Dementia and drugs
Eclampsia
Define epilepsy
Recurrent tendency to have seizures (>2 >24 hours apart) with no apparent cause
Define seizure
Spontaneous, uncontrolled, intermittent abnormal electrical activity in the brain
What are the qualities of ictus/ epileptic seizures?
Eyes open
Synchronous movements
Can occur in sleep
What are the risk factors of epilepsy?
> 20 or 60<
FHx
Premature birth
Alzheimer’s
Outline the pathophysiology of epilepsy
Normal balance between GABA (-) and glutamate (+) shifts towards glutamate
- Glutamate is more excitatory
Define prodrome
Nonspecific behavioural symptoms that can occur in the hours/days before a seizure
Define aura
More specific sensory disturbances (bad feeling, strange smells ect) that can occur before a seizure
What are the 2 classifications of seizure?
Generalised
Partial/focal
Are most seizures generalised or focal?
Focal
Define generalised seizure
Simultaneous onset of electrical discharge throughout the whole cortex, and ALWAYS is associated with loss of consciousness/awareness
How long do epileptic seizures usually last?
30-120 seconds
Define focal seizure
Electrical discharge is limited to one area of the brain, but can later become generalised
Outline the process of an epileptic seizure
Prodrome -> aura -> ictal event/seizure -> post ictal period
Define post ictal period
The period after a seizure
What are the symptoms in a post ictal period?
Headache
Confusion
Todd’s paralysis (temporary paralysis and muscle weakness)
Dysphasia
Amnesia
What symptom of a post ictal period is specific to epilepsy?
Sore tongue
What are 5 types of generalised seizure?
Tonic-clonic/grand-mal
Absence
Myoclonic
Tonic
Atonic/akinetic
What are 5 features of tonic-clonic seizures?
Often no aura
Loss of consciousness
Tonic phase: rigid and stiff limbs (fall)
Clonic phase: muscles jerking
Period of drowsiness, confusion, coma after
What are 4 features of absence seizures?
Usually occurs in children
Cease of activity, stares and pales for a few seconds
Amnesia of attack
3-Hz spike on ECG
What is the feature of myoclonic seizures?
Sudden isolated jerk of limb, face or trunk
- May suddenly fall
What is the feature of tonic seizures?
Sudden intense stiffening usually with grunt/cry
- NOT followed by jerking
What is the feature of atonic seizures?
Sudden loss of muscle tone (floppy) and cessation of movement causing a fall
What are 3 types of focal seizures?
Simple partial seizure
Complex partial seizure
Partial seizure with secondary generalisation
Define simple focal seizure
No LOC or memory and awareness is unimpaired, no post-ictal symptoms
Define complex focal seizure
Affecting awareness at some point, and patient is unaware and there is a post ictal period
Define focal seizure with secondary generalisation
Focal seizures spread widely, causing a secondary generalised seizure
2/3 of patients have this
Where do most complex focal seizures arise from?
Temporal lobe
What are the features of a simple focal seizure?
Isolated limb jerking
Head turning away from side of seizure
Todds paralysis
What are the features of a complex focal seizure?
Hallucinations
Lip smacking
Automatism
What are most secondary generalised seizures?
Tonic-clonic
What are the features of temporal lobe seizures?
Aura- deja but, hallucinations, fear ect
Anxiety o out of body experiences
Dysphasia
Post-ictal period
What are the symptoms of a frontal lobe seizure?
Motor features such as posturing or peddling
Jacksonian march- marches up or down homunculus starting in face or thumb
Post-ictal Todd’s palsy (of limbs involved in seizure)
What are the symptoms of a parietal lobe seizure?
Sensory disturbances- tingling or numbness
What are the symptoms of occipital lobe seizures?
Visual phenomenons - spots, flashes ect
What are features that differentiate epilepsy from syncope?
Tongue biting
Head turning
Muscle pain
LOC
Cyanosis
Post-ictal symptoms
How is epilepsy diagnosed?
Must have at least 2 seizures 24+ hours apart
ECG- not diagnostic
MRI with hippocampus imaging
CT head to check for lesion
FBC to check for metabolic causes
Define status epilepticus
Complication of epilepsy
Seizure >5 mins OR more than one seizure within 5 mins
What are the symptoms of status epilepticus?
Convulsive: jerking, grunting, drooling
Non-convulsive: no jerking, confusion, unable to speak
How is status epilepticus treated?
IV or rectal benzodiazepines
- lorazepam or buccal midazolam
Second line = phenytoin
How are tonic-clonic seizures treated?
Men + non-childbearing women: sodium valporate
Childbearing women: lamotrigine/levetiracetam
How are tonic/atonic seizures treated?
Men: sodium valoprate
Women: lamotrigine
How are myoclonic seizures treated?
Men: sodium valoprate
Women: levetiracetam
How are absence seizures treated?
Ethosuximide
2nd is the usual
How are focal seizures treated?
Lamotrigine or levetiracetam
- Carbamazepine, oxcarbaepine, zonisamide
What are 2 side effects of sodium valoprate?
Teratogenic
Hair loss and growing back curly
Weight gain
Oedema
What is a side effect of carbamazepine?
Agranulocytosis
Aplastic cytosis
What are the side effects of ethosuximide?
Night terror and rash
What are 2 side effects of lamotrigine?
Steve Johnson syndome
Leukopeni
How does sodium valoprate work?
Increases GABA
How does carbamazepine work?
Increases refractory period of sodium channels
How does lamotrigine work?
Na channel blocker
What are some surgical treatments for epilepsy if drugs are ineffective?
Surgical resection for hippocampal sclerosis or tumour
Vagal nerve stimulation
What are the causes of status epilepticus?
Abruptly stopping treatment
Alcohol abuse
Poor therapy compliance
When can epilepsy patients drive?
After they have been free from daytime seizures for a year
Define spina cord compression/myelopathy
Compression of the spinal cord resulting in upper neurone signs and symptoms specific to the site of compression
What are 2 causes of spinal cord compression?
Vertebral body neoplasms
Secondary malignancy from lungs, breast, prostate ect
What are 2 consequences of spinal cord compression?
Disc herniation- centre moves out of the outer part
Disc prolapse- nucleus pulposus moves and can create a bulge in the disc