Neuro Flashcards
What is the classic histology of a medulloblastoma
Small, blue cells with rosette patterns
Which CN does not carry any parasymp fibres?
2
Which allelle has increased risk of developing alzheimers
E4
What characterises syncope from seizures
Short post-ictal period- quick recovery
Vision worse going down the stairs
4th nerve palsy- limited depression, adduction of eye and persistent dipolopia
What signs would you see on examination of a Lower Motor Neurone lesion
Hypotonia and hyporeflexia
Because these are anterior horn cells so abolishes voluntary and reflex responses of the muscle
What is associated with early onset alzheimers?
Amyloid precursor protein
Which cells are destroyed in MS
Oligodendrocytes- responsible for the myelin production in the CNS
What is Broca’s dysphasia and what part of the brain does it affect?
Speech is non-fluent, comprehension normal, repetition impaired- affects the inferior frontal gyrus
What is Wernicke’s dysphasia and what part of the brain does it affect?
Inability to grasp the meaning of spoken words and sentences is impaired.
Speak normal words fluently but doesn’t make sense with a jumble of words. Affects the superior temporal gyrus
What brain lobe would be affected in touch perception/asterognosis
Parietal
Which nerve damage causes weakness of foot dorsiflexion
Common peroneal
What lobe of the brain is affected in touch perception
Parietal
What would occlusion of the anterior cerebral artery cause?
Contralateral hemiparesis and sensory loss with the lower extremity being more affected than the upper -> supplies the medial side of the cerebral hemisphere
What would occlusion of the posterior cerebral artery cause?
Contralateral hemianopia with macular sparing -> supply of blood to occipital lobe is blocked so visual processing is lost
What would occlusion of the middle cerebral artery cause
Supplies the motor and sensory cortices more likely to affect upper limbs than lower.
Unilateral droop of the face.
Language centres affected if stroke on dominant side
What is Weber’s syndrome?
When branches of the posterior cerebral artery are occluded -> ipsilateral CN 3 palsy, contralateral weakness of upper and lower extremity
Locked in syndrome is damage of which artery?
Basilar
What lobes does the tentorium cerebelli seperate
Occipital lobe
What lobe lesion may cause acalculia?
Parietal lesion
Unilateral cerebellar lesions cause problems on which side of the body
Ipsilateral
What are the afferent and efferent limbs of the corneal reflex
Afferent- opthalmic
Efferent- facial
What part of the dura mater seperates the cerebral hemispheres?
The falx cerebri
Which CN is affected in nystagmus?
CN VIII (vestibulocochlear)
What are astrocytes involved in?
Physical repair, form the blood-brain barrier, remove excess potassium ions, provide physical support
Infarcts in which lobes cause superior and inferior quadrantanopia?
PITS- parietal inferior, temporal superior (on contralateral side
Hallucinations occur in seizures of which lobe?
Temporal
Damage to what part of the thalamus causes hearing impairment?
Medial geniculate nucleus
What is myasthenia gravis?
Fatiguable, painless, muscle weakness that improves with rest
Degeneration of which neurotransmitters cause Huntingdon’s disease?
ACh and GABA
In a hypoglossal nerve lesion the tongue will deviate to which side?
The affected side
What can lacunar strokes cause?
Isolated hemiparesis, hemisensory loss or hemiparesis with limb ataxia
Strong association with hypertension
In vagus nerve lesions which side will the uvula deviate too?
Contralateral side of lesion
Describe lateral medullary syndrome/Wallenbergs
Following the occlusion of the posterior inferior cerebellar artery.
Cerebellar features: ataxia, nystagmus
Brainstem features: ipsilateral- dysphagia, facial numbness, cranial nerve palsy
Contralateral: limb sensory loss
DANVAH mnemonic- dysphagia, ipsilateral Ataxia, ipsilateral nystagmus, Vertigo, Anaesthesia, ipsilateral Horner’s syndrome
What is the pathophysiology behind myasthenia gravis
Autoimmune condition of the neuromuscular junction where antibodies are made against Ach receptors.
75% of patients have a thymoma
What is the tx for myasthenia gravis?
Acute: pyridostigmine, IV immunoglobulin or thymectomy
Long term: steroids eg pred+ azathioprine
What is the ix for myasthenia gravis?
Bloods- Ach receptors antibodies
CT chest for thymoma
EMG: single fibre
What tract processes crude touch? Where do they cross the spinal cord?
The anterior spinothalamic tract- cross at the spinal segment they enter
What tract carries fine touch, proprioception and vibration
Dorsal collumns
What tracts is responsible for pain and temp sensation?
Lateral Spinothalamic tract
Most common cause of meningitis in adults?
Strep Pneumoniae
What nerve promotes secretion from the parotid gland?
glossopharyngeal
What receptors do opiods act on?
Delta, Mu and Kappa
Bradycardia, bradypnoea and pinpoint pupils classic findings in an overdose
What are upper motor neurone signs?
Muscle weakness, spasticity, hyperreflexia and clonus
What are lower motor neurone signs?
Originate in the anterior horn of the spinal cord so asymmetric weakness, flaccid paralysis, fasciculations, hyporeflexia and muscle atrophy
First line treatment for migraine with N+V?
NSAID/paracetamol + antiemetic eg sumitriptan
What is a contraindication to a lumbar puncture?
Raised ICP
What are absence seizures?
Usually in children- patient stares blankly then abruptly returns to normal.
Mx- sodium valproate or lamotrigine
What the signs of primary lateral sclerosis?
Progressive and bilateral upper motor neuron weakness
What resp measurement should be monitored in guillian-barre syndrome?
Forced Vital Capacity
How does a subarachnoid haemorrhage present?
A severe sudden onset occipital headache. May have stiff neck, decreased consciousness and focal neurological deficit
Presentation of a cluster headache
Unilateral peri-orbital headaches with ipsilateral ptosis, lacrimation, conjunctival injection and rhinorrhea.
Happen in clusters with silent periods in between
What 5HT3 anatagonist can make parkinsons symptoms worse?
Metoclopramide
Signs of internuclear opthalmoplegia
Failure to adduct eye on affected side and nystagmus in contralateral side
What drug can used to reduce raised ICP?
Mannitol
What is spared in stroke
The forehead- indicates lower motor neuron problem
First line prophylactic treatment of migraine?
Amitriptyline
Are extradural haemoatomas supra or infratentorial?
Supra
What is the first step of ix in suspected stroke
non-contrast CT head
What to do next if ischaemic stroke is suspected?
Loading dose of aspirin and considered thrombolysis
What features suggest frontal lobe epilepsy?
Head/leg movements
Post ictal weakness
Jacksonian march (clonic movements travelling proximally)
What can be given to lower mortality in confirmed bacterial meningitis
Dexamethasone IV
What does a pyramidal pattern of muscle weakness mean?
In Upper Limb: extensors weaker than flexors
In Lower Limb: flexors weaker than extensors
What is neologism?
Making up new words or phrases
What is the most common cause of encephalitis?
Usually viral caused by herpes simplex 1
Thunderclap headache is associated with what?
Subarachnoid Haemorrhage
What are symptoms of a subdural haemorrhage
Fluctuating levels of consciousness and progressive neurology
Classic CT sign of a subdural haemorrhage
Cresent shaped collection of blood
Characteristics of a extradural haemorrhage
Head injury with deterioration in consciousness followed by a lucid interval.
Where is the bleed from an extradural haemorrhage usually from?
The middle meningeal artery or vein -> blood accumulates between the bone and dura mater
First line tx of tonic clonic seizures
Sodium Valproate and lamotrigine (women)
What does +ve rombergs test indicate?
Dorsal column dysfunction (visual input is required for proprioceptive deficits)
In a cerebellar syndrome is Romberg’s test positive or negative?
Positive
Characteristics of a tonic-clonic seizure?
Loss of consciousness and tonic (muscle tensing) and clonic (muscle jerking) episodes.
Associated tongue biting, incontinence, groaning and irregular breathing
Prolonged post ictal period
Characteristics of an atonic seizure
Brief lapses in muscle tone causing the patient to fall, not more than 3 mins, consciousness is retained
Characteristics of a myoclonic seizure
Present as sudden brief muscle jerks of a limb, trunk or face
What are upgoing plantars a feature of?
An upper motor neuron lesion on the affected side
What do cholinesterase inhibitors do?
Maintain higher levels of acetylcholine to attach to nicotinic acetylcholine receptors to facilitate muscle contraction -> alleviates muscle weakness (used in myasthenia)
An INR greater than what is a contraindication for thrombolysis?
INR >1.7
A blood pressure greater than what is a contraindication for thrombolysis?
180/110
What is the acute tx of a migraine?
NSAID (aspirin, naproxen, ibuprofen), antiemetic if gastroparesis, triptans (5HT agonist) eg sumitriptan, rizatriptan, eletriptan
What is the prophylaxis of a migraine?
1st- amitriptyline or propanolol
2nd- topiromate/valproate
3rd- pizotifen
What secondary treatment should be commenced post stroke in a patient with atrial fibrillation?
Warfarin or DOAC
What secondary treatment should be commenced post stroke in a patient?
Clopidogrel for long term antiplatelet therapy
What is guillain barre syndrome?
Progressive, symmetrical, distal weakness associated with flaccidity and hyporeflexia (LMN signs) on a background of a recent viral illness.
What is the main surgical intervention for subarachnoid haemorrhage?
Endovascular coiling
What is the Cushings Reflex, what does it result in?
A physiological response to raised ICP.
Increased blood pressure, decreased heart rate and irregular breathing
Describe the mechanism of the Cushing’s reflex
Raised ICP caused sympathetic and parasympathetic nervous systems to be activated.
In the first stage sympathetic > parasympathetic so greater blood flow resistance and hypertension and heart rate.
Barareceptors in the aortic arch detect this and triggers the parasymp response via the vagus nerve -> slows heart rate
Increased pressure on the brainstem can also can irregular breathing
Treatment for encephalitis
IV aciclovir
What are the features of corticobasal degeneration
Parkinsonian features, apraxia (unable to do tasks when asked to)
DANISH mnemonic for cerebellar stroke/syndrome dysfunction
Dysdiadochokinesia (inability to perform rapid alternating movements)
Ataxia
Nystagmus
Intention tremor (tremor during voluntary movement eg finger nose test)
Slurred speech
Hypotonia
What is the brains main inhibitory neurotransmitter
GABA- acts of gaba receptor
What is the brains main excitatory neurotransmitter?
glutamate acts on the NDMA receptor
What are automatisms?
Semicoordinated, repetitive motor activities associated with impaired awareness. eg lip smacking, grabbing, plucking
What type of seizures are automatisms seen in?
Temporal Lobe
What drugs can worsen symptoms of myasthenia gravis?
Beta blockers, certain antibiotics eg gentamicin, lithium
What are the three aspects of the Bamford criteria for a total anterior circulation infarct?
- Unilateral hemiparesis or hemisensory loss
- Higher cognitive dysfunction eg dysphasia or hemispatial neglect
- Homonymous hemianopia
What is a posterior circulation syndrome stroke (POCS) and its criteria
Damage to the area of brain supplied by posterior circulation eg cerebellum or brainstem
One of the following for dx:
- Cranial nerve palsy and a contralateral motor/sensory deficit
-Bilateral motor/sensory deficit
-Conjugate eye movement disorder (e.g. horizontal gaze palsy)
-Cerebellar dysfunction (e.g. vertigo, nystagmus, ataxia)
-Isolated homonymous hemianopia with macular sparing
What is a lacunar stroke (LACS)
Subcortical stroke (in deep part of brain) that occurs secondary to small vessel disease. No loss of higher cerebral function eg dysphasia
What is the diagnostic criteria for a lacunar stroke?
One of the following needs to be present for a diagnosis of a LACS:
-Pure sensory stroke
-Pure motor stroke
-Sensori-motor stroke
-Ataxic hemiparesis (weakness and ataxia on the same side)
From what time of symptom onset should thrombolysis be given for ischaemic stroke?
4.5 hours
Mx of essential tremor
Propanolol
Hyperattenuation would suggest which kind of stroke?
Haemorrhagic
Hospital treatment of status epilpticus?
Lorazepam twice within 5-10 mins of last dose then phenytoin
What nerves are affected in pseudobulbar palsy and what does it cause?
CN 9,10+12
Causes swallowing and speech difficulties
What is the test for impairment of motor function in the muscles served by the L5 nerve root?
Power of dorsiflexion of the big toe
What is the test for impairment of motor function in the muscles served by the L4 nerve root?
Foot inversion
What is the test for impairment of motor function in the muscles served by the L3 nerve root?
Knee extension
What is the test for impairment of motor function in the muscles served by the L2 nerve root?
Hip flexion
What would a lacunar stroke result in?
Pure motor dysfunction
An UMN lesion affects which tract
The pyramidal/corticospinal tract
A TAC stroke affects what vessels
Contralateral anterior and middle cerebral
A basal ganglia/extrapyramidal pathway leads to what features?
Parkinsonism/hypokinesis traits
Or hyperkinesis eg huntington’s chorea
Features of myotonic dystrophy?
Dysarthria, frontal balding, strong grip
Progressive muscle atrophy MND affects which motor neurones?
Only lower motor neurones
Spinal ALS MND affects what neurones?
Simultaneous upper and lower motor neurones
Primary lateral sclerosis affects which motor neurones?
Upper motor neurones
Main function of vestibulospinal tract
Activate the anti-gravity extensor muscles
Main function of the tectospinal tract?
Reflex to visual and auditory stimulus
Main function of reticulospinal tract?
Control of breathing and cardiac control
Where does the tectospinal tract originate and end?
Superior colliculus of the midbrain and extends down the cervical spine
Describe a subflacine herniation
-When one half of the cerebrum herniates across
the midline.
-cause compression of the anterior cerebral artery
-lead to motor and/or sensory weakness.
Describe cerebellar tonsillar herniation
-Cerebellum moves inferiorly
-Compresses medulla
-Lead to resp distress/death
Describe central herniation
Central part of the brain inferiorly compresses brainstem
Describe transcalvarial herniation
Defect in skull and brain herniates out
1st+2nd line treatment for generalised tonic clonic seizure?
1st:Sodium valproate or lamotrogine
2nd: levetiracetam or topiramate
1st line treatment for absence seizures?
Ethosuximide or sodium valproate
1st +2nd line treatment for myoclonic seizures?
1st-Sodium Valproate
2nd- Levetiracetam
Treatment for focal seizure
Lamotrigine/carbamazepine
1st+2nd line treatment for unclassified seizures?
1st-sodium valproate
2nd-Lamotrigine/topiramate
What the mechanism of action of metoclopromide?
D2 receptor antagonist therefore can block extra-pyramidal pathway leading to side effects such as acute dystonia and chronically tardive dyskinesias
Triad of juvenile myoclonic epilepsy?
Myoclonic jerks, absence seizures and generalised tonic-clonic seizures
First line treatment in status epilepticus?
Buccal midazolam or Rectal diazepam (benzodiazopines)
Treatment for trigeminal neuralgia?
Carbamazepine, gabapentin, pheytoin
What is the caution with topiramate?
Contraindicated in pregnancy, need very effective contraception- can impair the effectiveness of hormonal contraceptions.
How does Brown Sequard syndrome arise?
Due to hemisection of spinal cord. Anatomical disruption of nerve fibre tracts in one half of spinal cord
Pathophysiology of brown sequard syndrome?
Ipsilateral weakness + loss of fine touch, joint proprioception and vibration as fibres decussate in the medulla.
Contralateral loss of pain and temp sensation as fibres of spinothalamic tract decussate in spinal cord
Which antibiotic can reduce seizure threshold?
Quinolones such as ciprofloxacin
What is the secondary prevention of stroke?
Clopidogrel 75mg once daily (alternatively aspirin plus dipyridamole)
Atorvastatin 20-80mg (not started immediately – usually delayed at least 48 hours)
Blood pressure and diabetes control
Addressing modifiable risk factors (e.g., smoking, obesity and exercise)
What would MRI of MS show?
- Periventricular lesions
- Discrete white matter abnormalities
- Areas of focal demyelination
- Active inflammatory plaques can be distinguished from inactive ones by using a contrast agent
Ix for trigeminal neuralgia?
MRI head
Tx for trigeminal neuralgia?
Carbamazepine first line, gabapentin, phenytoin
Foot drop is damage to which nerve
Common peroneal nerve
What is given after thrombolysis in ischemic stroke if presenting within 4.5 hours of symptoms?
Aspirin 24hrs after treatment with alteplase for a period of 2 weeks once repeat CT has excluded new haemorrhagic stroke
If hyperacute treatments are not offered in stroke what is given?
Aspirin 300mg orally once daily for two weeks
In temporal lobe epilepsy which structure could be damaged and what symptoms would it result in?
Hippocampus can cause long term deficits in memory
Features of Wernicke’s Encephalopathy
- Ataxia
- Confusion
- Ocular abnormalities: this can include gaze-evoked nystagmus, spontaneous upbeat nystagmus, and horizontal or vertical ophthalmoplegia
Aetiology of myotonic dystrophy
Genetic mutation leading to trinucleotide repeats in DMPK gene
What is obstructive or non-communicating hydrocephalus?
When flow of CSF blocked along one or more narrow passages connecting the ventricles leading to dilation of more upstream ventricles eg third and fourth
What is communicating hydrocephalus?
CSF can exit the ventricular system but absorption impaired- commonly due to problems in the subarachnoid space such as haemorrhage
Symptoms of hydrocephalus?
Early morning headaches, N+V, lethargy and visual disturbances
How long after a TIA or stroke should a patient not drive
1 month if satisfactorily recovered
What is conductive dysphasia?
Presents with fluent speech but an inability to repeat words.
What is dysarthria?
Inability to coordinate the muscles of speech leading to problems with articulation. They have no problem producing speech but do not pronounce the words well
What is global aphasia?
Inability to understand, repeat, and produce speech.
First line investigation for MS
MRI brain and spine with contrast
How does progressive supranuclear palsy present?
Parkinsonism and vertical gaze palsy (hard to look up)
More symmetric and tremor negative parkinsonism
Ix for a TIA
-MRI to look for alternative pathologies
-Carotid ultrasound
-Echo: to look for carotid thrombus
-24hr tape for atrial fibrillation
-Blood tests for glucose and lipids
Gold standard ix for cervical myelopathy?
MRI of cervical spine
Where does the lateral corticospinal tract decussate and what does it innervate?
Decussates in medulla
Innervates the distal/appendicular muscles
Where does the anterior corticospinal tract decussate and what does it innervate?
Decussates in spinal cord at segmental level
Innervates trunk and axial muscles
