Conditions Part 1 Flashcards
defintion for Stroke and TIA
a cerebrovascular event is a clinical syndrome caused by disruption of blood supply to the brain characterised by rapidly developing signs of focal or global disturbance of cerebral functions lasting for more than 24 hours ore leading to deaths
A transient ischaemic attack refers to a similar presentation that resolves within 24 hours
how common is stroke or TIA
about 150 00 have a stroke in the UK every year
53 000 deaths each year
further 20 000 have a TIA
who is affected the most by stroke or TIA
uncommon if <40yrs, rates greater in Asian and black africans than white
M>F
causes for stroke
cerebral infraction
- 70%
- arterial thrombus in-situ atheromatous carotid, vertebral or cerebral arteries
- cardiac embolus following AF, valvular disease, prosthetic valves, MI (>30% of stroke)
primary haemorrhage
- 15%
- high BP
- trauma
- aneurysm rupture
subarachnoid haemorrhage
- 5%
- arterious aneurysms
- arterio-venous malformations
Uncertain type
- 5%
causes for TIA
mainly due to
- micro-emboli from heart or atheromatous plaques
- fall in cerebral perfusion due to cardiac dysrhythmia, postural hypotension, dec flow due to atheroma
what are the different stages of stroke
minor stroke - stroke-in-evolution - completed stroke
pathogenesis of stroke
vessel obstruction –> brain ishaemia –> infract –> infracted area surrounded by a swollen area which is structurally intact but does not function (ischaemic penumbra) –> this can regain neurological function
within the ischaemia area –> hypoxia –> fall in ATP –> glutamate release –> Ca2+ channels open –> free radial release –> inflammation and necrosis
RF for stroke and TIA
hypertension, smoking, DM, heart disease (valvular, ischaemia, AF), peripheral vascular disease, polycythaemia vera (too much blood cells), past TIA, cortid bruit, the pill, hyperlipidaemia, alcohol, clotting disorder, syphilis
symptoms of stroke and TIA
either sudden onset or step-wise progression of symptoms
symptoms depends on whether ischaemic/haemorrhagic and which artery affected
cerebral hemisphere infarct -50%
- contralateral hemiplegia (weakness of the body) initially flaccid then spastic
- contralateral sensory loss
- homonymous hemianopia (blindness of half visual field)
- dysphasia
brainstem infarction - 25%
- quadriplegia
- disturbances of gaze/vision
- locked-in syndrome
lacunar infarct - small infarct around the basal ganglia, internal capsule, thalamus, pons - 25%
- pure motor/sensory or mixed signs
- ataxia (lack of voluntary movement)
- intact cognition/consciousness
differential diagnosis for stroke and TIA
CNS tumour subdural haemorrhage drug overdose hemiplegic migraine - hepatic encephalopathy
further investigation for stroke and TIA
Brain CT - often normal in ischaemic stroke for the first few hours
MRI - more accurate thatn CT
echocardiography - if suspected cardiac cause/origin
fundoscopy, bloods, carotid duplex ultrasound, BP, hypoglycaemia, hyperglycaemia, dyslipidaemia
management for stroke and TIA
immediate mangement
- ABCDE
- thrombolysis needed? if yes then imaging
- brain imaging (CT - quick and easy)
- cerebral infarction - CT exclude haemorrhag. give immediate thrombolytic therapy, or 300mg aspirine if contra-indicated
- cerebral haemorrhage - do not give anto-coagulant and neurosurgery
later management
- MR angiography (MRA) or CT angiography - to discover surgical location and confirmation of location of infarct
- carotid dopplet and duplex scanning - carotid occlusion
low dose aspirin as primary prevent if 10-year risk of CHD >10%
treatment for stroke and TIA
RF identify and reduce
anti-hypertensive therapy
anti-platelet therapy (clopidogrel monotherapy)
anticoagulants - heparin and warfarin
surgery - internal carotid endarterectomy if carotid occlusion
definition for sub-arachnoid haemorrhage
bleeding into the subarachnoid space
how common is subarachnoid haemorrhage
constitutes about 6% of first stroke
causes for subarachnoid haemorrhage
intracranial arterial aneurysms - berry anerurysms
non-aneurysmal peri-mesencephalic haemorrhage
other vascular abnor - arteriovenous malformation
RF for subarachnoid haemorrhage
larger aneurysm - more likely to ruputre
hypertension
smoking
excessive alcohol intake
FH
genetic
adult polycystic kidney disease (around 10% have berry aneurysm)
symptoms of subarachnoid haemorrhage
sudden, severe, typically occipital headache lasting few seconds - ‘thought I had been kicked at the back of my head’ thunder clap headache ?
vomiting
collapse
seizures
coma/drowsiness
neck stiffness - due to meningeal irritation by blood
complete/partial palsy of oculomotor nerve
marked rise in BP
sentinel headache - resolve with no other symptoms - due to ‘warning leak’ from aneurysm
differential for subarachnoid headache
other causes of stroke
meningitis
trauma
idiopathic thunderclap headche
further investigations for subarachnoid haemorrhage
CT - detect 90% of SAH within first 48 hrs
lumbar puncture - if CT -ve, CSF is uniformly bloody early on and turn yeloow later on as blood is broken down into bilirubin like piss
management for SAH
refer all SAH to neurology team asap
re-exam CNS often to see any further development of the haemorrhage
repeat CT if deteriorating
nimodipine - Ca2+ antagonist which reduce vasospasm and consequent mobility from cerebral ischaemia
endovascular coiling
prognosis for SAH
up to 60% die within first 30 days, 10% die immediately with no symptoms
definition for peripheral neuropathy
damage or disease affecting the peripheral nerves which can be a mononeuropathy or polyneuropathy or mononeuritis multiplex (several separate mononeuropathies) and can be acute or chronic
what is mononeuropathy
a process affecting a single nerve (including CN)
what is mononeuritis multiplex
multiple mnoneuropathy and or multifocal neuroapthy affects several or multiple nerves
what is polyneuropathy
diffuse, symmetrical disease, usually commencing peripherally
classed broadly into demyelinating and axonal types, depending upon which principal pathological process predominates, often impoosible to separate these clinically
what is myelopathy
disease of the cord
radiculopathy
disease affecting nerve roots and plexopathy, the brachial or lumbosacral plexus
causes of mononeuropathy
- nerve compression eg carpal tunnel
- trauma eg ulnar elbow trauma
- radiotherapy
- tumours
- fractures
causes of mononeuritis multiplex
DM vasculitides immune-mediatd disease eg RA, SLE infections eg leprosy, HIV, lyme disease sarcoidosis amyloidosis chemical agents
causes of polyneuropathy
metabolic eg DM, RF, hypothyroid, hypoglycaemia
vasculitides
malignancy
inflammation
infection eg leprosy, HIV, syphilis, Lyme disease
nutritional eg vitamine B12, B1, E, B6 folate deficiency
inherited syndrome
toxins eg lead, arsenic
drugs
amyloidosis
pathogenesis of nerve damage
demyelination - Schwann cell dmage - myelin sheath damage - slowing of conduction (Guillain-Barre Syndrome)
axonal damage - nerve fibre dies back from neuropathy, conduction velocity normal though as axon continuity is maintained by surviving fibre (eg in toxic neuropathies)
Wallerian degeneration - changes follwoing nerve section - axon and distal myelin sheath degenerate over weeks
compression
infarction - micoinfarction of vaso nervorum as in DM and arteritis
inflitration - by inflam cells (eg in leprosy and sarcoidosis and neoplastic granulomas)
what are the symptoms of peripheral neuropathy
sensory
- -ve signs - numbeness, tremor, gait abnor
- +ve signs - tingling, pain, itching, crawling, pins and needles
motor
- -ve signs - weakness, tiredness, heaviness, gait abnor, reduced reflexex
- +ve signs - cramps/myalgia, tremor, fasciculations
further investigation for peripheral neuropathy
usually clinical and detailed history and exam
can do bloods, genetic tests, lead levels and immuno tests
management for peripheral neuropathy
treat the cause, involve phsyio and OT
treat neuopathic pain with amitriptyline or nortriptyline
what is the most common type of mononeuropathy
median nerve (C6-T1) - carpal tunnel syndrome
how does carpal tunnel syndrome present
at wrist - aching pain in hand/arm esp at night
parasethesiae in radial 3.5 fingers
relieved by dangling out of bed or shaking
sensory loss and weakness of abductor pollicis brevis +/- wasting of thenar eminence
tinel’s sign - tap flexor/anterior aspect of wrist = tingling and pain
phalen’s test -symptoms are reproducable on passive maximal wrist flexion
treatment for carpal tunnel syndrome
local steroid injection +/- decompression surgery
what is the syndrome caused by ulnar nerve mononeurpathy
ulnar (c7-T1) - cubital tunnel syndrome
presentation for cubital tunnel syndrome
clawing of the hand due to weakness of medial wrist flexors etc
sensory loss over medial 1.5 fingers
treatment for cubital tunnel snydrome
remove pressure over elbow for ulnar nerve
what is the nerve root of radial nerve
C5-T1 , Saturday night palsy
what is the presentation of radial nerve neuropathy
wrist drop and weakness of flexors
sensory loss to dorsal aspect of thumb
treatment for radial nerve neuropathy
recovery within a few months usually (damage via compression against the humerus eg arm draped over a hard chair for hours)
what are the different types of polyneuropathy
Guillain-barre syndrome & charcor-Marie-Tooth Syndrome
presentation of guillain-barre syndrome
acute
weakness of distal limb muscles +/- numbness
this progresses proximally and may lead to paralysis
loss of tendon reflexes, respiratory and facial muscles may become weak
monophasic - does not recur
often caused due to minor infection as it induce AB response against nerves
what is the treatment for Guillain-barre syndrome
diagnosis confirmed by nerve conduction studies - prolonged distal motor latency IV Ig
presentation of charcot-marie-tooth syndrome
personal muscular atrophy, distal limb wasting and weakness that slowly progresses over years, legs might resemble inverted champaign bottles
in mild cases, pes cavus and clawing of toes
what does MS stand for
Multiple Sclerosis
what causes MS
cell-mediated autoimmune condition
what does MS normally occur
discrete plaques of demyelination occur at multiple CNS sites - the demyelination heals poorly causing relapsing and remitting symptoms, prolonged demyelination causes axonal loss and clinically progressive symptoms
who is affected the most by MS
commoner in temperate areas and less common in Black Africans/Asians
what is the presentation of MS
unilateral optic neuritis, numbness or tingling in the limbs, leg weakness, brainstem or cerebellar symptoms, Bell’s palsy, relapses and remits –> secondary progression. Can be primarily progessive
what test can be used to diagnose MS
usually clinical but MRI can be used to confirm or support diagnosis
treatment for MS
disease modifying therapy, interferon beta, non-immunosuppressives, monoclonal antibodies, methylprednisolone for acute relapses
what is proximal myopathy
symmetrical weakness of proximal upper and/or lower limbs
causes of proximal myopathy
broad range of underlying causes including drugs, alcohol, thyroid disease, osteomalacia, idiopathic inflammatory myopathies, hereditary myopathies, malignancy, infections and sarcoidosis
presentation for proximal myopathy
gradual onset, proximal not distal weakness, symmetrical, preserved tendon reflexes, normal sensation, muscle wasting but maybe muscle hypertrophy
fever with inflammatory myopathies
hypotonia is common in some myopathies
further tests for proximal myopathy
urinalysis –> myoglobinuria
bloods –> raised CK
complication of proximal myopathy
respiratory failure, aspiration pneumonia, rhaboymolysis, chest/spine/joint deformities
