Neurology Flashcards
What is a glioma?
A Neuroepithelial tumour usually seen within the hemispheres though can be anywhere in CNS
2 main types; astrocytomas and oligodendrogliomas
Why are tumours of neuronal cells only present in childhood?
Fully differentiated neurons can’t multiply or give rise to neoplasms so tumours have to occur before completion of differentiation
What is a medulloblastoma?
Childhood brain tumour arising from the cerebellum
What is a neurofibroma?
Tumours deriving from endoneurium which is a layer of connective tissue around the myelin sheath of each nerve in the PNS
Personality changes and disinhibition would indicate a tumour located where?
Frontal lobe
Describe the sensory (ascending) tracts in the Dorsal Horn
Responsible for fine touch, vibration and proprioception
Ipsilateral (decussates in medulla)
Fasciculus cuneatus (lateral) responsible for T6 and above
Fasciculus gracilis responsible for below T6
Describe the anterolateral part of the sensory tract?
Anterior spinothalamic responsible for crude touch and pressure
Lateral spinothalamic responsible for pain and temperature
Contralateral (decussates in spinal cord)
Describe the pyramidal tracts of the motor (descending) pathway
Anterior corticospinal and lateral corticospinal tracts are responsible for voluntary movement of the limbs
Anterior is ipsilateral and lateral is contralateral
Which tracts are known as the extrapyramidal motor tracts?
All coordinate INvoluntary movements
Tectospinal = head and neck movements in response to visual stimuli
Vestibulospinal tract = posture and balance
Rubrospinal = fine motor control
Reticulospinal = medial for contraction and increases tone, lateral inhibits contraction and decreases tone
What does DANISH stand for?
Dysdiadokinesia = impairment of rapid alternating movements
Ataxia = broad gait
Nystagmus
Intention Tremor
Scanning dysarthria = slow or poorly articulated speech
Hypotonia
Headache red flags
Worse in morning
Wakes you up
Worse when coughing or leaning forward
Associated with vomiting
Gold standard test for the brain tumour
MRI
Describe a subfalcine herniation
Asymmetrical expansion of a hemisphere causes compression of the cingulate gyrus under the falx cerebri
Can cause compression of the anterior cerebral artery branches
Symptoms = weakness in contralateral leg
Describe a tentorial herniation
Medial part of the temporal lobe hernaites over the tentorium cerebelli
Causes compression of ipsilater 3rd cranial nerve -> pupil dilation, reduced eye movements
Describe tonsillar hernation
Displacement of the cerebellar tonsils through the foramen magnum
Compresses brainstem so compromises the respiratory centre in the medulla -> life threatening
Describe transcalvarial herniation
Swollen brain herniated through any defect in the dura and skull
What’s the main cause of a subarachnoid haemorrhage?
A ruptured berry aneurysm
These are formed from a congenital weakness of the elastic tissue in the artery wall
Symptoms of a subarachnoid haemorrhage?
Sudden onset of a thunderclap headache - worst, occipital, during strenuous activity “hit on back of head”
Nausea and vomiting
Neck stiffness and photophobia if meningeal irritation
3rd nerve palsy if aneurysm is on posterior communicating artery
Investigation if you suspect a brain haemorrhage
Unenhanced CT
If inconclusive then a lumbar puncture looking for blood
Treatment for a subarachnoid haemorrhage
Bed rest and support
Control any hypertension
Nimodipine (Ca channel blocker) prevents vasospams which can cause ischaemia
How would you treat a brain aneurysm?
Endovascular treatment placing platinum coils via a catheter into the aneurysm to promote thrombosis and ablation of the aneurysm
Direct surgical clipping may be needed
Causes of a subdural haemorrhage
Acute = trauma ruptures the bridging veins Chronic = brain atrophy causes bridging veins to be stretched
Symptoms of a subdural haemorrhage
Altered state of consciousness following trauma or a fall
Chronic = headaches, confusion, urinary incontinence, weakness, seizures…
What does a subdural haemorrhage look like on a CT scan?
Semilunar shape
Midline shift
Management of a subdural haemorrhage
No immediate treatment as they often resolve on their own
Must involve neurosurgery
Serial imaging
Can be drained surgically
What is the pterion?
Thinnest part of the skull
Join of the temporal, parietal, frontal and sphenoid bones
Causes of an extra dural haemorrhage
Trauma causes shearing stress that separates the bone and the dura
Most commonly trauma to the pterion which damages the middle meningeal artery
Symptoms of an extra dural haemorrhage
Head trauma that causes a brief loss of consciousness, then lucidness then further deterioration
Headache
Contralateral hemiparesis - damage to stalks that attach cerebrum to brain stem and contain ascending and descending tracts
Ipsilateral pupil dilation - temporal lobe can herniate and compress oculomotor nerve
Management of an extra dural haemorrhage
If expanding, immediate neurosurgical treatment
If small and patients are neurologically intact then conservative treatment
What produces the myelin sheath?
In CNS, oligodendrocytes
In PNS, Schwann cells
How many spinal nerves are there?
31 pairs C1-8 T1-12 L1-5 S1-5 Co1
Which dermatome is the nipple in?
T4
Which dermatome is the umbilicus
T10
At what level does the spinal cord end?
L1-2
Where should a lumbar puncture be inserted?
Between L3-4
Myoclonus
Quick involuntary muscle jerk
E.g. hiccups, hypnic jerk when falling asleep
Brief activation of muscles
Dystonia
Sustained or intermittent muscle contractions that cause abnormal movements
Often initiated or worsened by voluntary action
Associated with overflow muscle activation
Chorea
Brief, irregular movements that move flit and flow from one body part to another
Patients often appear restless or fidgety
Tics
‘Un” voluntary repetitive movements or vocalisations
Suppressible for a short period of time but this causes a lot of anxiety
Pathology of Parkinsons Disease
Loss of dopaminergic neurons in the substantia nigra
Surviving cells contains Lewy bodies
Early signs of Parkinsons Disease
Anosmia Depression and anxiety Sleep disorder Urinary urgency and constipation Hypotension Restless leg syndrome
Motor problems associated with Parkinson’s Disease
Akinesia Tremor (pin-rolling) Rigidity Stooped posture Shuffling gait with reduced arm movements Speech and swallowing difficulties
Investigations for Parkinsons Disease
Dopamine Transporter Imaging using SPECT or PET
Management of Parkinson’s Disease
1st Line for those with motor symptoms = Levodopa
= converted to dopamine in the brain - need more over time, on-off problems
No motor symtoms = L Dopa, dopamine agonists or MAO inhibitors
What is Parkinsonism?
Any conditions that causes TRAP (extrapyramidal) symptoms = Tremor, Rigidity, Akinesia, Postural disturbances
Can be caused by anything affecting the nigrostriatal dopamine pathway e.g. antipsychotics (block D2 receptors)
What is MS?
Multiple Sclerosis
T-cell mediated inflammatory disorder causing multiple plaques of demyelination throughout the brain and spinal cord (CNS only) occurring sporadically over years
Investigations for MS
MRI = areas of demyelination
Lumbar puncture = oligoclonal bands in CSF with no corresponding bands in the serum
Management of MS
Symptoms - physiotherapy or baclofen for pyramidal dysfunction. Gabapentin for neuropathic pain
Acute - oral or IV steroids
Disease modifying - Tecfidera (oral), interferons, glutamir acetate (injection)
What is myaesthenia gravis?
Auto-immune disorder of the NMJ
Antibodies to ACh receptors -> signals don’t get through
Symptoms of myaesthenia gravis
Weakness that gets worse throughout day - fatigability. Particularly, extraocular, facial and bulbar weakness
Drooping eyelids
Double vision that comes and goes
Can cause a respiratory crisis cos of weak muscles of respiration
Investigations for myaesthenia gravis
Anti-AChR antibodies
Anti-MuSK antibodies
Management of myaesthenia gravis
Acute - acetylcholinesterase inhibitors, IVig
Steriods then move to steroid-sparing e.g. azathioprine
AVOID GENTAMICIN
What is Guillan-Barre Syndrome?
Acute demyelination disorder that usually occurs after infection with campylobacter or CMV
Causes ascending weakness
Symptoms of Guillan-Barre Syndrome
Post infection
Weakness and sensory loss
Loss of tendon reflexes
Investigation and treatment of Guillan-Barre syndrome
Confirm with nerve conduction studies
IVIg given within first 2 weeks can reduce severity and duration of paralysis
Pathogenesis of Huntington’s Disease
Autosomal dominant with age-dependent penetrance (Anticipation)
Extra CAG repeats (>20) so increased glutamines on the protein -> neurotoxic. Unstable during meiosis so it gets worse each time its passed down and appears earlier
Loss of basal ganglia which causes flattening of ventricles
Caudate nucleus is atrophic
Loss of cells in cerebral cortex
Presentation of Huntington’s disease
Fidgetiness, difficulty concentrating, clumsiness
Chorea, inability to walk
Difficulty speaking and swallowing
Patients usually die 10-20 years after 1st onset of symptoms
What is Duchenne Muscular Dystrophy?
X-linked recessive disorder (1/3 spontaneous) causing progressive muscle wasting and weakness
The mutation is in the dystrophin gene which codes for dystrophin proteins that connect actin filaments to cell membrane and ECM.
-> progressive loss of muscle cells -> muscle wasting and weakness
Presentation of DMD
Developmental delay (boy not walking by 18 months) Gower’s sign = put hands down to push themselves up Toe walking - calf hypertrophy Exaggerated lumbar lordosis
Investigations for DMD
Screen looking for raised creatinine kinase
Genetic testing to confirm
Management for DMD
No curative treatment - usually disabled by 10, die in 20s
Steroids may delay progression
Physiotherapy
What is Spinal Muscular Atrophy?
Autosomal Recessive disorder that causes loss of anterior horn cells in spinal cord
Usually a deficiency in SMN1 gene which causes motor neuron loss
Presentation of Spinal Muscular Atrophy
Floppy and weak baby - hypotonia and muscle weakness
Respiratory failure is resp. Muscles are affected
Management of Spinal Muscular Atrophy
Treatment using similar SMN2 gene which prevents essential exon7 being spliced out
Prevents progression but doesn’t stop whats already happened
Most common causes of meningitis
Streptococcus pneumonia Neisseria Miningitidis (meningococcus)
Describe Streptococcus Pneumonia with regards to meningitis
Most common type of meningitis Alpa Haemolytic Gram positive cocci in chains High risk of developing with diabetes, cochlear implants or skull fractures There is a vaccine
Describe Neisseria Meningitidis with regards to meningitis
Gram negative cocci in pairs
Symptoms due to endotoxin
More common in young children and adults
12 capsular groups and theres a vaccine for ACWY
Treatment for Bacterial Meningitis
Ceftriaxone IV 2g bd (chloramphenicol is penicillin allergy) and Dexamethasone
If listeria suspected (anyone >60 or immunocompromised) add amoxicillin
Most common cause of encephalitis in UK
Herpes Simplex Virus
Presentation of encephalitis
Personality and behavioural changes
Confusion, reduced consciousness, coma
Speech disturbance
Seizures
Treatment for Encephalitis
Suspected HSV or VZV then acyclovir IV immediately
Long-term complications are common including memory impairment, personality change, epilepsy
Absense seizure
Loss of awareness and vacant facial expression <10secs
Maybe slight eye flutterings but no motor symptoms
Patient may be unaware
Myoclonic Seizure
Jerk movements
Tonic seizure
Stiffening of the body. No jerking
Atonic seizure
Sudden collapse with loss of muscle tone and consciousness
Tonic clonic seizure
Tonic stiffening followed by clonic jerking phase
Possible incontinence after convulsions
Slow return to consciousness followed by drowsiness, confusion and headaches
Management of Epilepsy
1st line for tonic clonic, tonic or atonic seizures = Sodium Valproate (or lamotrigine)
1st line for myoclonic = Sodium Valporate (or levetiracetam)
Sodium Valporate is teratogenic so avoid in women of child-bearing age
Many AEDs can make contraceptives ineffective
In spinal cord, where is the white and grey matter?
Grey matter is in the middle with anterior and dorsal horns
White matter around the outside containing the ascending and descending tracts
Describe nigrostriatal dopamine pathway
Pars compacta in substantia nigra of the midbrain
Controls movement
More dopamine = more movement
Describe mesocorticolimbic dopamine pathway
Travels from VTA of midbrain to prefrontal cortex then to nucleus accumbens
Controls mood/reward
More dopamine = higher mood
Describe tuberoinfundibular dopamine pathway
From hypothalamus to pituitary
Controls prolactin release
More dopamine = less prolactin
What foramina does CN I pass through?
Olfactory
Cribiform plate
What foramina does CN II pass through?
Optic Nerve
Optic Canal
What foramina does CN III pass through?
Oculomotor Nerve
Superior Orbital Fissure
What foramina does CN IV pass through?
Trochlear
Superior Orbital Fissure
What foramina does CN V pass through?
Trigeminal
V1 = SOF
V2 = Foramen rotundum
V3 = Foramen ovale
Wht foramina does CN VI pass through?
Abducens
Superior orbital fissure
What foramina does CN VII pass through?
Facial Nerve
Internal auditory meatus then stylomastoid foramen
What foramina does CN VIII pass through?
Vestibulocochlear
Internal auditory meatus
What foramina does CN IX pass through?
Glossopharyngeal
Jugular Foramen
What foramina does CN X pass through?
Vagus Nerve
Jugular Foramen
What foramina does CN XI pass through?
Accessory Nerve
Jugular foramen
What foramina does CN XII pass through?
Hypoglossal
Hypoglossal Canal
Describe what CN III does and signs of a CN III palsy
Eye movements (MR, SR, IR, IO), pupil constriction, accomodation, eyelid opening
Palsy = Ptosis, ‘down and out’ eye, dilated, fixed pupil
Describe what CN IV does and signs of a palsy
Superior oblique eye movement
Palsy = down and in gaze, vertical diplopia
Describe what CN VI does and signs of a palsy
Lateral rectus eye movement
Palsy = Eye cant move outwards, horizontal diplopia
If there is a CN X palsy, which way will the uvula deviate?
Away from the site of the lesion
If there is a CN XII palsy, which way will the tongue deviate?
Towards the side of the lesion
Which cranial nerve nuclei are located in the medulla oblongata?
9, 10, 11 and 12 Glossopharyngeal Vagus Accessory Hypoglossal
Which cranial nerve nuclei are located in the posterior part of the pons?
5, 6, 7 and 8 Trigeminal Abducens Facial Vestibulocochlear
Which cranial nerve nuclei are located in the central part of midbrain?
3 and 4
Oculomotor
Trochlear
Which blood vessel lies deep to the pterion?
Middle meningeal artery
Biceps reflex, which nerve?
C5 (6)
Triceps reflex, which nerve?
C7
Supinator/brachioradialis reflex, which nerve?
C6
Patellar reflex, which nerve?
L4
Ankle reflex, which nerve?
S1
Describe neurofibromatosis
Type 1 and 2. 1 is more common (90%)
Autosomal dominant
Chromosome 17 (type 1), 22 is type 2
Neurofibromas, cafe-au-lait spots and freckling, learning disability
Treatment for status ellipticus
IV lorazepam
IM midazolam (can also do buccal or nasal)
Can add phenytoin IV
If not working, can add phenobarbitone
