Neuro - general Flashcards
Commonest complication of meningitis
hearing loss
RF for SAH
Polycystic kidney disease
Alcohol, smoking, HTN
What do lacunar infarcts affect?
Small vessels around the basal ganglia, internal capsule, thalamus, pons
Clinical dx of epilepsy
need 2 or more unprovoked seizures occuring >24h apart
Commonest organisms in neonate meningitis
Extended labour, infection in previous pregnancy –> Group B streptococci
Late neonatal infection-> E. Coli
Listeria monocytogenes
Commonest organisms in infants + young children meningitis
Gram +ve cocci –> Strept. Pneumoniniae,
Unvaccinated –> Haemophilus influenzae type B,
Gram -ve diplococci –> Neisseria meningitidis
Commonest organisms in children meningitis
Gram +ve cocci –> S pneumoniae
Unvaccinated –> Haemophilus influenzae type B
Gram -ve diplococci –> N. meningitides
Commonest organisms in adult meningitis
Gram -ve diplococci –> N. meningitidis (80%)
Gram +ve cocci –> S. pneumoniae
H. Influenzae, L. monocytogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa
Commonest organisms in elderly + immunocompromised meningitis
eldelry, cheese/unpastuerised milk, alcoholics –> L. monocytogenes
Alcoholism + recent chest infection –> pneumococcal meningitis
Immunocompromise + CN involvement –> Listeria meningitis
Gram +ve cocci –> S. pneumoniae
TB
Commonest organisms in hospital-acquired + post traumatic meningitis
Klebsiella pneumoniae, E. coli, Pseudomonas aeruginosa, Staph. aureus
Contraindications to LP
- signs of increase ICP (decreased consciousness, bad headache, frequent fits)
- focal neurology
- severe shock
- sepsis
- Coagulopathy
- open skin lesion at the site of entry
Indications for LP
2/4 of the following are present • Headache • Fever • Altered mental status of unknown aetiology • Meningism
Causes of hydrocephalus in young people
- Congenital malformations
- Brain tumours
Causes of hydrocephalus in older people
- Brain tumours
- Strokes
What is a non-communicative hydrocephalus?
Also called obstructive
Impaired flow of CSF from the ventricular system
Causes of non-communicative hydrocephalus
Lesions of 3, 4 ventricle, cerebral aqueduct
Acquired aqueduct stenosis
SOL in posterior fossa compressing the 4th ventricle
Tentoral herniation
Intraventicular haematoma
Tumours
What is a commmunicative hydrocephalus?
Impaired CSF reabsorption in the subarachnoid villi due to either
- increased production
- decreased reabsorption
What can cause a comminicative hydrocephalus?
Thickining of the leptomeninges +/- involvement of arachnoid granulations
- infection
- SAH
- meningitis
- tumours
- NPH
Increased in CSF viscosity - increased protein count
Excessive CSF production - choroid plexus papilloma
What is hydrocephalus ex vacuo?
apparent ventricular expansion as a compensatory change due to brain atrophy + shrinkage (e.g. Alzheimer’s) – no increase in CSF pressure
What is normal pressure hydrocephalus?Causes?
CSF pressure remains normal or is only intermittently raised as measured by LP
o Idiopathic chronic ventricular enlargement
o Long white matter tracts are damaged leading to gait + cognitive decline
o Probably caused by chronic communicating hydrocephalus
The condition responds to a reduction in CSF pressure and/or a CSF diversion procedure
What is multiple sclerosis?
- Cell – mediated autoimmune condition
- Repeated episodes of inflammation of the nervous tissue in the brain + spinal cord –> causing loss of the insulating myelin sheath
- Multiple areas of scar tissue form along the neurones –> this slows/blocks the transmission of signals to + from the brain + the spinal cord –> movement + sensation may be impaired
What is progressive bulbar palsy?
A type of MND - LMN
Any lesion affecting cranial nerve 9-12 at nuclear, nerve or muscle level
Nasal speech
Nasal regurgitation of food (esp. fluids - palatal weakness)
Decreased gag reflex
Absent jaw jerk
Wasted fasciculating tongue
Emotions not liable
What is pseudobulbar palsy?
A type of MND - UMN
UMN lesion to the lower brainstem (CN 9-11)
result of damage of motor fibres travelling from the cerebral cortex to the lower brainstem
Monotonous speech
Donald duck speech
Dysarthria
Dysphagia
Increased gag reflex
Brisk jaw jerk
Shrunken immobile spastic tongue, no fasciculations
Emotional liability
UMN limb spasticity + weakness
What is myasthenia gravis?
Chronic autoimmune disorder of the post-synaptic membrane at the neuromuscular junction in the skeletal muscle resulting from binding of autoantibodies to components of the NMJ (e.g. most commonly against the nicotinic Ach receptor but also to associated proteins)
What is a myasthenic crisis?
a complication of MG characterised by worsening muscle weakness resulting in respiratory failure that requires intubation + mechanical ventilation
What is the Eaton-Lambert syndorme?
a rare neuromuscular disorder most commonly seen in patients with small cell lung cancer
Proximal muscle weakness that improves on repetition (unlike MG)
DDx for myasthenia gravis and how to differentiate (4)
• Eaton-Lambert syndrome
o Proximal muscle weakness improves on exercise
• MS
o Hyperreflexia
o Extensor plantar response
• MND
o Features of UMN + LMN disease
• Horner’s syndrome
o Usually unilateral
o Miosis
Most common muscles to be affected in Myasthenia Gravis
Muscles of eyes + face
Condition may progress to affect respiratory muscle function –> myasthenic crisis
Myasthenia gravis assosciations
- Other autoimmune conditions (e.g. pernicious anaemia)
- Thymoma development (breakdown in immune tolerance thought to arise in thymus)
Thymic hyperplasia more common than thymoma
Thymomas are present in 20% of patients with MG // Thymic hyperplasia occurs in 75% of MG patents // 30-50% of patients with thymoma also have MG
What is progressive muscular atrophy?
A type of MND
Affects LMN only
What is primary lateral sclerosis?
A type of MND
Loss of Betz cells in motor cortex
Mainly affects UMN
No LMN signs
Aetiology of GBS
Following a GIT or URT infection (2-3 weeks after infection)
Antibodies to the infectious organism also attack antigens in peripheral nervous tissue
Immune mediated attack on myelin sheath or Schwann cells of sensory + motor nerves
Organisms Campylobacter jejuni CMV HIV EBV mycoplasma
RF for trigeminal neuralgia
- Old age
- MS
Most frequent causes of encephlitis
Infectious encephalitis
Immunocompromised
Autoimmune/paraneoplastic
- Infectious encephalitis - Herpes Simplex Virus (temporal lobes)
- Immunocompromised - also consider CMV (ventricles), toxoplasmosis, Listeria
- Autoimmune/paraneoplastic - may be associated with antibodies
What is BPPV?
Benign paroxysmal positional vertigo
peripheral vestibular disorder that manifests as sudden, short-lived episodes of vertigo elicited by specific head movements
How to differentiate BPPV from
Meniere’s
Viral labyrinthitis or vestibular neuronitis
Migraines
Central disorders
Meniere’s disease lasts for hours
Viral labyrinthitis or vestibular neuronitis lasts for days
Migraines are variable
Central disorders can be constant
Aetiology of Meniere’s
- Over production or impaired absorption of endolymph in the inner ear
- Build-up of endolymphatic pressure (known as hydrops, rupture in membrane separating endolymph + perilymph - mixing + possible raise in pressure)
- Endolymphatic hydrops - Progressive distension of the membranous labyrinth - this may injure the vestibular system (vertigo) or the cochlea (hearing loss)
Difference between Type 1 and Type 2 neurofibromatosis
What do they affect
What are they made up of
Where is the mutation
When do the symptoms first appear
Type 1
• Typically affects nerves in the extremities + the skin – grow along peripheral spinal nerves + just beneath the skin surface
• Neurofibromas made of a mixture of Schwann cells, fibroblasts, immune cells
• Mutation in NF1 Chr 17
• Symptoms in childhood
Type 2
• Typically affects the brain, spinal cord and cranial nerves
• Neurofibromas are typically schwannomas
• Mutation in NF2 Chr 22
• Symptoms in adults <40 mostly in the 20s
Aneurysms of the posterior communicating artery can lead to…
Oculomotor nerve palsy
Vertigo indicates disturbance to…
- Inner ear
- vestibulocochlear nerve
- Brainstem
Gentamicin can be toxic to.and it can cause
The vestibular apparatus
vertigo
Were is the huntingtin (HTT) gene located?
On the short arm of Chr 4
What does the mutated huntingtin protein do?
Induces apoptosis in neurones
Degeneration + death of medium spiny GABAergic neurones in the caudate + putamen
Why is chorea a symptom of Huntington?
There is pathology in the striatum resulting in atrophy of mainly the caudate but also the putamen
As a result there is loss of inhibition of movements
Pathophysiology for Parkinson’s disease
Alpha synuclein misfolds and begins to accumulate in cells –> cells lose their ability to degrade the protein –> formation of Lewy bodies and Lewy neurites
Clinical course of subdural haematoma
Patient is well after the injury but subsequently deteriorates + loses consciousness as haematoma forms
• Fluctuations in consciousness
Clinical course of extradural haematoma
• Hx of trauma /head injury that causes loss of consciousness, followed by a lucid interval after which the patient deteriorates
Aetiology of subdural haemorrhage
Tearing of the bridging veins from the cortex to one of the draining venous sinuses
common in alcoholic (coagulation problems, brain atrophy) and elderly pt (brain atrophy)
Aetiology of subarachnoid haemorrhage
Intracranial aneurysm rupture (usually berry aneurysm in the Circle of Willis)
Traumatic brain injury
Aetiology of extradural haemorrhage
Pterion fractures
Fractures involving the foramen spinosum (it is where the middle meningeal artery passes through)
RF for SAH
- AD PKD
- Neurofibromatosis T1
- Ehlers-Danlos syndrome type IV, Marfans
- FHx
- HTN
- Smoking
- Cocaine
- Excessive alcohol intake
What is the difference between medical + surgical oculomotor palsy?
Medical - normal pupillary function (not dlated) with complete loss of eyelid + oculomotor somatic function
- Non-traumatic
- Pupil sparing (responds to light, not dilated) - parasympathetic fibres carried on the outside of the nerve not affected
- Ischaemic cranial neuropathy secondary to microvascular complications
- Assosciated with DM, HTN, hyperlipidaemia
Surgical - dilated pupil with loss of function with compete loss of eyelid + oculomotor somatic function
- Traumatic
- Non pupil spared (pupil is dilated) -parasympathetic fibres carried on the outside of the nerve compressed in trauma + pupil is not spared
- Posterior communicating artery aneurysm
Partial third nerve palsies with normal papillary function can be related to progressive comprehensive lesions - need to be excluded
Conditions that can cause facial paralysis
Herpes zooster Sarcoidosis Lyme disease causes bell's palsy (bacterial cause) Bell's pals Stroke
Anterior circulation of the brain arteries
Anterior cerebral artery
Middle cerebral artery
Anterior cerebral artery supplies
Medial aspect of frontal + parietal lobes
branch of internal carotid
Middle cerebral artery supplies
lateral surface of hemispheres, subcortical structures
branch of internal carotid
Posterior cerebral artery supplies
Occipita lobe + inferomedial part of the temporal lobe
arises form the basillar artery
a) Normal INR
b) therapeutic range of INR for pt on warfarin for AF or other conditions that increase the risk of thrombosis
c) Stop warfarin if INR…
d) interventions if INR >X or if…
a) 1.5
b) 2-3
c) 5-9
d) >9 or if active bleeding- vitamin K, FFP
Most important complication of cerebellum or middle cerebral artery infarction
Cerebral oedema –> Increased ICP
Can cause brain herniation
Other signs - quadriparesis, oculomotor abnormalities, new facial palsy
Which prognosis is worse? Haemorrhagic or ischaemic stroke?
Hemorrhagic
Difference between simple partial and complex partial seizures
In complex partial seizures there is impairment of consciousness + patient cannot remember the events after the attack
In simple partial seizure patient knows that something is happening and can remember what happened afterwards
Main causes of LOC in
Young patients
Middle aged patients
Elderly patients
Vasovagal syncope
Vasovagal syncope + arrhythmias
Orthostatic hypotension
Factors assosciated with a better MS prognosis
- Age onset <25 years
- Optic neuritis or sensory symptoms at presentation (rather than cerebellar symptoms)
- A long interval (>1 year) between relapses
- Few lesions on MRI
- Full recovery from relapses
Progressive MS has a worse prognosis than relapsing-remitting MS
Cause of amaurosis fugax
Symptoms
Fundoscopy
assosciated with
retinal artery emboli
painless unilateral loss of vision
short duration
black curtain descending
oedema + cherry red macula
GCA, TIA
Spinal claudication = Spinal stenosis
Cause
Presentation
Exacerbating/relieving factors
Caused by narrowing of the spinal canal due to spondylosis
Presents with: a)back pain + b) sciatica
Pain worse when spine is extended going downhill, walking
Pain better when spine is flexed going uphill, sitting
Meningitis buzzwords
- Long, extended labour
- Late neonatal infection
- Gram +ve cocci
- Gram -ve diplococci
- Unvaccinated
- Elderly, cheese/unpasturised milk/alcoholics
- Group B streptococcus
- E.coli
- Streptococcus pneumoniae
- Neisseria Meningitides
- Haemophilus influenza
- Listeria monocytogenes
Most common type of meningitis in immunocompromised individuals? Causative organism
Enteroviruses are the most common cause of meningitis in immunocompetent adults in the UK (viral infection – aseptic meningitis)
Duration of migraines vs cluster headaches
Migraines - 4-72h
Cluster headaches 15mins - 3h
Difference bn TN + temporal arteritis
TN usually 2nd and 3rd divisions of trigeminal nerve affected
TN rarely affects forhead alone
TN assosciated with MS
Temporal arteritis usually only affects forhead
Temporal arteritis assosciated with polymyalgia rheumatica
What is Meningococcal disease?
Meningococcal disease – meningitis +/or septicaemia caused by Neisseria meningitidis
Non-blanching purpuric rash is a sign
IV benzylpenicillin
What kind of herniation does LP cause?
Uncal herniation
3rd CN palsy vs 6th CN palsy
3rd - posterior communicating artery aneurysm [eye down + out] (also superior cerebellar artery aneurysm)
6th - increased ICP [convergent squint +/- failure to abduct eye]
Where is the
motor cortex
somatosensory cortex
found
motor cortex - frontal lobe
somatosensory cortex - parietal lobe
Why is there a cherry red spot on fundoscopy in GCA?
Occlusion of ciliary and retinal arteries due to inflammation –> pale retina
Macula receives blood supply from choroid (supplied by the posterior ciliary arteries)
How to differentiate between the different causes of back pain
Spinal stenosis
Spondylosis
Spondylolisthesis
Spinal tumours
Spinal stenosis
Pain relieved when sitting/leaning forwards
Caused by narrowing of the spinal canal due to spondylosis
Presents with: a)back pain + b) sciatica
Pain worse when spine is extended going downhill, walking
Pain better when spine is flexed going uphill, sitting
Spondylosis
Pain worse in the morning + following activity
Spondylolisthesis
Pain worse when standing
Spinal tumours
Pain is unremitting
Associated with systemic features e.g. weight loss, night sweats
What is a scotoma
Area of depressed vision within the visual field
This finding is seen in lesions of the optic nerve which are commonly assosciated with demyelination e.g. MS
Which are the 3 clinical phenotypes of MS
Relapsing remitting MS (RRMS) – patients most often fine, occasionally suffer from relapses + get acute symptoms which then resolve
Secondary progressive MS (SPMS) – they become gradually more and more disabled, may have more relapses, incomplete recovery
Primary progressive MS (PPMS) – they start progressing immediately without the initial relapsing + remitting stage
Not all RR patients convert to SP
Difference between
Essential tremor/familial tremor
PD tremor
Cerebellar tremor
Essential tremor/familial tremor
Absent at rest
Appear on action
6-12 Hz
Fine amplitude
May be ameliorated by alcohol or beta blockers
No other parkinsonian symptoms are present
PD tremor
Present at rest, exacerbated by concentration
Disappear on action
3-7 Hz
Coarse amplitude
Commonly affects the distal limbs asymmetrically
Cerebellar tremor
Increases in magnitude throughout the movement to be maximal on approaching the target
4-6 Hz
Associated with other cerebellar signs (DANISH)
Where is the lesion
Complete involvement of the legs (either sensory or motor)
Involvement of arms
Complete involvement of the legs (either sensory or motor) = lesion is higher than L1
Involvement of arms = lesion is higher than T1
Central postural control is maintained by three systems
Cerebellar problem vs proprioceptive problem
vestibular
visual
proprioceptive
Cerebellar problem - patients can’t stand with their feet together even if their eyes are open
Proprioceptive loss - patients can stand with their feet together if they have their eyes open but lose their balance once they close their eyes (positive Romberg’s test)
What does the Romberg’s test test?
Proprioception
Straight leg raise test
The Straight Leg Raise (SLR) test can be used to determine if patient has true sciatica.
The test is positive when raising the leg between 30 to 70 degrees causes pain to occur and radiate down the leg to at least below the knee, and often all the way down to the great toe
