Neuro revision Flashcards
What is the role of hippocampus in memory?
Consolidation of declarative memories.
Strengthen synapses with cortex.
What are complications of meningitis?
Cerebral infarction
Subdural empyema
Cerebral abscess
Epilepsy
Outline how prions cause disease?
Abnormal prion proteins aggregate - spongiform encephalopathies.
Embolus within the brain can originate from where?
Atria - AF
Carotid atheroma debris
Aneurysm
What structure initiates REM sleep?
Pons
What happens in stages 2+3 of sleep on EEG?
Theta waves with sleep spindles and K complexes
What happens in stage 1 of sleep in EEG?
alpha waves and theta waves
What happens to muscle tone in REM sleep?
Loss of muscle tone - inhibitory of LMNS by descending glycernergic fibres from RF.
What are some reversible causes of dementia?
Depression, delirium Trauma Vitamin deficiency Alcohol Thyroid disorder
How is the CAM score used to differentiate between delirium + dementia?
If 2 or more then delirium likely:
- Acute
- Altered consciousness
- Inattention
- Disorganised thinking
What symptoms are typical of lewy body dementia?
Fluctuations in cognitive impairment
Parkinson symptoms
Visual hallucinations
Frequent falls
What are features of fronto-temporal dementia?
Altered social behaviour + personality
Impaired judgement + insight
Speech - mutism/aphasia eventually
What are 2 types of partial seizures?
Temporal - auras, memory rush
Frontal - abnormal movements on contralateral side.
What investigations would you do if you suspected epilepsy?
History - pre, during and after
Collateral history
EEG
MRI and ECG to to rule out other causes.
Differential diagnosis for epilepsy.
Vascular - stroke, TIA Infection - abscess Trauma - intracerebral haemorrhage Autoimmune - SLE Metabolic - hypoglycaemia, hypoxia, thyroid Iatrogenic - alcohol withdrawal Neoplasia - mass
What 3 things are tested on GCS.
Eye opening
Verbal response
Motor response
What are the 6 stages of motor response in GCS.
Obeys commands Localise to pain Normal flexion Abnormal flexion Extension None
What are the 4 stages of eye opening in GCS.
Spontaneous
To sound
To pressure
None
What is the name given to the pathophysiology of a raised ICP.
Cytotoxic cellular oedema
What are the signs and symptoms of raised ICP?
Headache Vomiting Visual disturbances CNVI palsy - abducens Decreased conscious level - RF ischaemia Infants - increasing head size
Which CN is vulnerable with raised ICP and why?
Abducens - emerges from posterior pons and courses close to skull.
What are 3 effects of tentorial/uncal herniation?
Pressure on MIDBRAIN:
CNII palsy
Cerebral peduncle - contralateral leg weakness
CVS and rest centres - decreased consciousness
What is the consequence of tonsillar herniation?
Decreased consciousness - compress CVS and resp centres
Explain why the Cushing’s reflex might occur.
Hypertension - ischeamia at medulla, increased sympathetic activation
Baroreceptor response - bradycardia
Ischaemia at resp centres - low RR
What 4 things can cause a raised ICP?
SoL
Increased cerebral blood volume
Increased CSF
Cerebral oedema
What might cause increased cerebral blood volume?
Venous outflow obstruction
Venous sinus thrombosis
What might cause cerebral oedema?
Meningitis
Encaphalitis
Infarction
Diffuse head injury
What might cause increased CSF?
Excess secretion - choroid plexus papilloma
Impaired absorption - hydrocephalus, benign intracranial hypertension
Give 3 examples of SoL.
Abscess
Haemorrhage
Tumour
What does normal CSF look like and contain?
Clear
Little protein + cells
Hyperosmotic to plasma - Na+, Cl-
What is the difference between non-communicating and communicating hydrocephalus?
Non-communicating = obstruction in ventricles. Dilation of ventricles superior to obstruction.
Communicating - outside ventricles - decrease absorption or increased production. Dilation of all ventricles.
What might cause non-communicating hydrocephalus?
Tumours- meningioma
What is idiopathic intracranial hypertension and who is it most common in?
Raised ICP without hydrocephalus or mass lesion.
Normal imaging but signs of raised ICP.
Obese young women after weight gain.
What is contusion.
Microhaemorrhages and small blood vessel leaks - blood mixes with cortical tissue.
Oedema - raised ICP - coma
What is concussion and its effects?
Concussion - temporary loss of brain function following head injury.
Stretching and injury to axons - impaired NT and blood flow - temp dysfunction
What is diffuse axonal injury?
Shearing of interface between grey and white matter - axonal death - cerebral oedema - raised ICP - coma
Describe the trend in consciousness associated with extradural haemorrhage.
- LOC from initial concussion- Reticular activating system damaged
- Lucid interval of recovery with ongoing headache
- Decline as haematoma grows and ICP increases
What complications are associated with extradural haemorrhage?
Permanent brain damage Coma Seizures Weakness Psuedoaneurysm Ateriovenous fistula = vasc malformations increase risk of future bleeds.
Which intracranial haemorrhage can be chronic and present like dementia?
Subdural in elderly as tension on bridging veins- confusion and cognitive decline
What are the CT changes as haemorrhage gets older?
Acute - hyper dense = brighter
Chronic - hypo dense = darker
What age group usually suffer from subarachnoid haemorrhage?
< 60
Which brain haemorrhage is associated with a sudden thunderclap headache?
Subarachnoid
Which type of brain haemorrhage can present with meningism despite no infection?
Subarachnoid
What investigation can aid diagnosis of subarachnoid haemorrhage?
Lumbar puncture -rbc present or xanthochromia = yellow from RBC breakdown
What are RF for subarachnoid haemorrhage?
FH
CT problems
Smoking
Alcohol
Why can ACA stroke cause a loss of control of micturition?
- Genitals is medial on motor homunculus
2. Supplies paracentral lobules - role in voluntary control of micturition.
Damage to which lobe can cause spatial neglect?
Right parietal lobe - neglect left side
An occlusion in which artery could result in contralateral homonymous hemianopia?
MCA, proximal - both superior and inferior optic radiations
An occlusion in which artery may cause issues in laying down new declarative memories?
PCA - supplies inferior temporal lobe where hippocampus is
What sensory changes might you see with PCA stroke?
Sensory loss on contralateral side - thalamus
What would be the effects of a distal basilar artery occlusion?
PCA also affected - bilateral occipital infarct - blindness
Bilateral thalamic infarct - anaesthatised
Bilateral midbrain infarction
What would be the effect of proximal occlusion of basilar artery?
Pontine vessels
Quadriplegia - corticospinal tract infarction.
Occlusion of which artery could cause a purely motor stroke?
Lenticulostriate artery - contralateral face, upper and lower limb
Occlusion of which artery could cause a purely sensory stroke?
Thalamoperforator artery - contralateral face, upper and lower limb
Other than stroke, name 4 other causes of ‘stroke mimics’?
Hypoglycaemia
Epilepsy
Migraine
Intracranial tumours, Infection
What deficits might be present if there is occlusion of ICA?
Contralateral paralysis of both upper and lower limbs, trunk and speech deficit.
What are 2 theories for anxiety?
Low GABA - BZD reduce anxiety
Low serotonin - SSRI’s reduce anxiety
What is the treatment for anxiety?
- SSRI
- CBT
- Pregabalin - GABA analogue
What are 3 theories for OCD?
- Re-entry circuit in basal ganglia
- Reduced serotonin
- PANDAS
What is PANDAS?
Sudden onset OCD symptoms after group A strep infection
Cross-reaction of antibodies with basal ganglia neurones.
What is the recommended treatment for OCD?
- CBT
- Exposure response prevention
- High dose SSRI - higher doses than depression
What is the pathophysiology of PTSD?
Hyperactivity of amygdala
Low cortisol - cortisol inhibits traumatic memory retrieval
What 3 things contribute to cause of depression?
Predisposing factors
Precipitating factors - triggers
Perpetuating factors - maintain
Give examples of perpetuating factors.
Social stressers - job, studies, unemployment, financial strain, housing, substance misuse
Give examples of precipitating factors.
Life events - losses, health, relationship break up
What are 5 positive symptoms of schizophrenia?
Auditory hallucinations Passivity experiences Thought withdrawal, broadcast + insertion Delusional perception Somatic hallucinations
What are negative symptoms of schizophrenia?
Underactivity
Low motivation
Social withdrawal
Self neglect
What are the 5 types of schizophrenia?
Paranoid Simple Hebephrenic Catatonic Undifferentiated
What is the pathophysiology of schizophrenia?
Underactive mesolimbic pathway
Overactive mesocortical pathway
What is the autoimmune hypothesis for schizophrenia?
Anti-NMDA encaphalitis
- ovarian teratoma antibodies bind to NMDA receptor in brain.
- Acute psychosis
What type of receptor is D2?
GPCR - Gi
What is the pathophysiology of catatonic schizophrenia?
Decreased movement although dopamine excess..
increased GABA inhibition.
What are organic causes of psychosis?
Delirium - infection
Hypercalcaemia
Hyperthyroidism
Drug/alcohol intoxication
What are the clinical features of a complete cord transection at C5?
- Loss of all sensory modalities at and below C5
- Loss of all motor modalities at and and below C5
- LMN signs at C5
- UMN signs below C5
- Priapism + hypotension - increased PS
What are common causes of complete cord transection?
Trauma Infarction Abscess Tumour Transverse myelitis
What are causes of brown-sequard syndrome?
Penetrating trauma Fractured vertebrae Abscess Tumour MS
What are causes of anterior cord syndrome?
Flexion injuries - dislocation/fractured vertebrae, herniated discs
Anterior spinal artery - atherosclerosis in elderly
Which tracts are affected in anterior cord syndrome?
Spinothalamic
Corticospinal
What type of trauma can cause central cord syndrome in elderly and younger patients?
Elderly - hyperextension
Young - hyperflexion
Other than trauma, what can cause central cord syndrome?
Syringomyelia
Cervical spine stenosis
Degenerative spinal disease- spondylosis
What are the clinical features of central cord syndrome?
Cape-like distribution - upper limbs > lower limbs (medial in tracts)
Motor function > Sensory
Distal > proximal
Bladder dysfunction and urinary retention
What is often responsible for the initial symptoms of central cord syndrome?
Obliteration of spinothalamic fibres decussating in ventral white commissure.
What are causes for posterior cord syndrome?
Spondylosis Spinal stenosis Infections Vit B12 deficiency Occlusion of posterior spinal arteries
Before removing the collar, what must the patient be?
Alert and orientated No language barrier Not intoxicated No midline posterior tenderness - palpate spine No focal neurological deficit No painful distracting injuries
Which grey matter horn do UMN synapse onto?
Ventral
What synapses in dorsal horn?
Spinothalamic onto secondary neurone.
Which part of the brain is affected in huntington’s disease?
Striatum - putamen
What are arteriovenous malformations?
Connections between arteries and veins.
Congenital.
What is the effect of arteriovenous malformations?
Blood flows artery to vein before supplying tissues.
Ischaemia
Heart has to work harder.
What is the pathophysiology of MS?
Sclerosis forms along neurones, slow transmission impairs movement and sensation.
How does MS usually present?
Visual symptoms due to demyelination of optic nerve.
A tumour at the cerebellopontine angle might affect which nerve?
CNVIII - ispilateral hearing loss
A patient presents with right sided facial droop, forehead and eyebrows are unaffected. Where is the lesion likely to be?
Left genu - corticonuclear fibres run in the genu of the internal capsule
What type of injury can cause anterior cord syndrome?
Flexion
What spinal cord syndrome is usually caused by chronic pathology, give examples?
Posterior cord syndrome
- spondylosis
- spinal stenosis
- infections
- B12 deficiency
Which spinal cord syndromes lead to bladder dysfunction and urinary retention?
Anterior and central
What is an example of evidence that 5-HT has a role in depression?
SSRIs increase synaptic levels of 5-HT and treat depression
Tryptophan (precursor) depletion induces depression
Lower 5-HT metabolites in depressed patients
What is an example of evidence that NA has a role in depression?
AMPT inhibits tyrosine conversion to L-dopa - causes depressive symptoms
TCAs and SNRIs treat depression
What is sleep apnoea?
Soft tissue in the neck transiently obstructed the airway during sleep. Hypoxia wakes people up.
The thalamoperforator arteries are a branch of which main artery?
PCA
What structural changes have been recorded in patients with Schizophrenia?
Enlarged ventricles
Reduced hippocampal formation, amygdala, prefrontal cortex
Where are D2 receptors highest in concentration?
Midbrain and striatum
How would damage to thalamus affect movement?
Decreased - theoretical decreased activation of motor cortex.
Why do UMN lesions lead to spasticity?
Loss of descending inhibition of LMNs - flexors more powerful resulting in spastic posture.
Why would a stroke affecting lateral motor cortex compromise swallowing?
lesion of UMNs which distribute LMN to the vagus nerve.
What is the mechanism explaining why somebody can experience no pain despite a significant injury?
Increased activity of enkaphalinergic neurones in the spinal cord. Activation of descending analgesic systems.
Which CN emerges ventrally from the ponto-medullary junction?
Abducens
Which CN emerges laterally from the ponto-medullary junction?
Facial n.
Rapid onset dementia in a young person might be suggestive of what condition?
Prion disease
How would a lesion in the arcuate fasciculus present?
Articulate words clearly
Unable to repeat the name of an object
Can point to the object the word refers to
