Neurology Flashcards
Describe symptoms of an extradural bleed
- developed a headache after head trauma
- confused and drowsy
- difficult to rouse
- biconvex shape on CT
What is an extradural haemorrhage?
- usually caused by rupture of middle meningeal artery
- in temporo-parietal region
- associated with fracture of temporal bone
- occurs between skull and dura mater
Where does a subdural haemorrhage occur?
- rupture of bridging veins in outermost meningeal layer
- occurs between dura mater and arachnoid mater
Describe the presentation of subdural bleeding
- crescent shape on CT and possible midline shift
- drowsiness, reduced consciousness, high ICP
- seizure
What is the pathophysiology behind subdural bleeding?
- usually occurs due to trauma
- turning/jerking injuries cause damage to the bridging veins and causes tears
- elderly and alcoholics have more brain atrophy making rupture more likely
Describe presentation of subarachnoid bleeding
- sudden onset
- severe thunderclap headache
- occurs due to strenuous activity
What is Guillan-Barré syndrome?
- an acute paralytic polyneropathy
- affects peripheral nervous system
- symptoms peak after 2-4 weeks, recovery can take months-years
What causes Guillan-Barré syndrome?
- triggered by infection
- associated with:
- campylobacter jejuni (MC)
- cytomegalovirus
- Epstein-Barr virus
What is the pathophysiology behind Guillan-Barré syndrome?
- occurs due to molecular mimicry
- B cells create antibodies against antigens on the pathogen
- these antibodies match proteins on nerve cells
- Abs then target myelin sheath of motor nerve cell or nerve axon
How does Guillan-Barré syndrome present?
- symmetrical ascending weakness (starting at feet)
- reduced reflexes
- peripheral loss of sensation/neuropathic pain
- progresses to cranial nerves and causes facial weakness
How is Guillan-Barré syndrome diagnosed?
- Brighton criteria
- nerve conduction studies
- lumbar puncture for CSF: raised protein, normal cell count and glucose
How is Guillan-Barré syndrome managed?
- IV immunoglobulins
- plasma exchange
- supportive care
- VTE prophylaxis
What is multiple sclerosis?
- chronic and progressive condition involving demyelination of neurones in the CNS
What is the epidemiology of multiple sclerosis?
- young adults (under 50)
- more common in women
- symptoms improve in pregnancy and postpartum
What is the pathophysiology of multiple sclerosis?
- myelin provided by Schwann cells in PNS and oligodendrocytes in CNS
- inflammation around myelin and infiltration of immune cells damages myelin causing symptoms
- re-myelination can occur in early disease, is incomplete in late disease > permanence
Why do symptoms of MS change over time?
- lesions vary in location over time
- different nerves are affected and symptoms change
- lesions are disseminated in time and space
- early course: relapsing-remitting attacks
What is the aetiology of multiple sclerosis?
- genetic
- EBV
- low vit D
- smoking
- obesity
What optical symptoms occur with multiple sclerosis?
- double vision: abducens (VI) lesions
- internuclear opthalmoplegia: problems with coordinating eye movements (III, IV, VI)
- conjugate lateral gaze disorder: affected eye cannot abduct (VI)
What is optic neuritis?
- unilateral reduced vision over hours to days
- central scotoma (enlarged blind spot)
- impaired colour vision
- pain on eye movement
- relative afferent pupillary defect
What is the general presentation of multiple sclerosis?
- sensory and cerebellar ataxia
- tremors
- incontinence
- limb paralysis
- trigeminal neuralgia, numbness and paresthesia
How is multiple sclerosis diagnosed?
- progressive symptoms over a year
- or 2 attacks disseminated in time and space
- MRI brain + cord showing lesions
- LP shows oligoclonal IgG bands in CSF
What are the types of disease course of multiple sclerosis?
- relapsing-remitting: episodes of disease followed by recovery - can be active and/or worsening
- 1º progressive: gradual deterioration without recovery
- 2º progressive: relapsing-remitting > worsening and incomplete remission
How is multiple sclerosis managed?
- acute episodes: IV methylprednisolone
- DMDs: β interferon
- mitoxantrone
What are differential diagnoses for multiple sclerosis?
- SLE, Sjrogen’s, encephalomyelitis
- Lyme’s, syphilis, AIDS
What is Parkinson’s disease?
- progressive reduction of dopamine in the basal ganglia leading to movement disorders
- substantia nigra produces dopamine
- asymmetrical symptom
What are the risk factors and epidemiology of Parkinson’s?
- family history
- male
- inc age
- e.g. 70y/o male
What are the symptoms of Parkinson’s?
- unilateral tremor: 4-6Hz
- cogwheel rigidity: jerky movement
- bradykinesia: shuffling gait, difficulty initiating movement, reduced facial expression
- anosmia
- postural instability
How is Parkinson’s diagnosed and what is the classic triad?
- clinically based on symptoms
- resting tremor, rigidity, bradykinesia
- DaTscan
How is Parkinson’s managed?
- Levodopa + decarboxylase inhibitor
- dopamine agonist e.g. bromocriptine
- COMT inhibitors e.g. entacapone: metabolises L-dopa
- Monoamine oxidase B inhibitors - rasagiline
How does levodopa work and what are the associated side effects?
- synthetic dopamine e.g. carbidopa
- taken alongside decarboxylase inhibitor e.g. benserazide
- becomes less effective over time
- leads to dyskinesias e.g. dystonia, chorea, athetosis
What is Huntington’s chorea and what is the pathophysiology?
- autosomal dominant condition with full penetrance
- trinucleotide repeat disorder in HTT in chromosome 4
- lack of GABA and excessive nigrostriatal pathway
What is genetic anticipation?
- more trinucleotide repeats leads to earlier onset of disease and increased severity
When does Huntington’s present and what is the prognosis?
- asymptomatic until age 30-50
- life expectancy: 15-20yrs after onset of symptoms
How does Huntington’s present?
- cognitive, psychiatric and mood problems > movement disorder
- chorea
- eye movement disorders
- dysarthria and dysphagia
- depression
How is Huntington’s diagnosed?
- genetic testing with pre and post-test counselling
- diagnosis if > 35 CAG repeats
How is Huntington’s managed?
- antipsychotics e.g. olanzapine
- benzodiazepines e.g. diazepam
- dopamine-depleting agents e.g. tetrabenzine
- antidepressants
What is myasthenia gravis?
- autoimmune condition causing muscle weakness
- progressively worse weakness with activity which improves with rest
- mostly affects proximal muscles and small muscles of head and neck
What is the epidemiology of myasthenia gravis?
- women under 40
- men over 60 (more related to thymoma)
What is the pathophysiology behind myasthenia gravis?
- Ach-R antibodies bind to postsynaptic NMJ receptors
- Ach unable to bind, stimulate receptor and trigger muscle contraction
- more used during activity and so more are blocked
- Abs activate complement system leading to damage at postsynaptic membrane
How does myasthenia gravis present?
- extraocular muscle weakness > diplopia
- eyelid weakness > ptosis
- dysphagia
- jaw fatigue
- slurred speech
- facial weakness
How can myasthenia gravis be examined?
- repeated blinking > ptosis
- prolonged upward gazing > diplopia
- repeated abduction of one arm > unilateral weakness
How is myasthenia gravis diagnosed?
- testing for antibodies: acetylcholine receptor (Ach-R) and muscle-specific kinase (MuSK)
- Edrophonium test
What is the edrophonium test for myasthenia gravis?
- IV dose of edrophonium chloride
- normally cholinesterase enzymes break down Ach but edrophonium blocks the enzymes
- stops Ach breakdown and and inc Ach levels
- relieves weakness temporarily
How is myasthenia gravis managed?
- reversible Ach inhibitors: pyridostigmine
- immunosuppression
- thymectomy
- monoclonal Abs: rituximab
What is myasthenic crisis?
- complication causing acute worsening of symptoms
- triggered by another illness e.g. resp tract
- can lead to resp failure > ventilation
- treatment with IVIG and plasma exchange
What is the pathophysiology of trigeminal neuralgia?
- can affect any combination of V1, V2 and V3
- 90% cases are unilateral
- triggers: cold weather, spicy food, caffeine, citrus
What are the 3 branches of the trigeminal nerve?
- V1: ophthalmic
- V2: maxillary
- V3: mandibular
What is the presentation of trigeminal neuralgia?
- intense facial pain
- comes on spontaneously, can last seconds to hours
- electricity-like shooting pain
How is trigeminal neuralgia treated?
- carbamazepine
How do tension headaches present?
- mild ache across forehead in band like pattern
- muscle ache in frontal, temporalis and occipitalis muscles
- come on and resolve gradually: no visual changes
What are the causes of tension headaches?
- alcohol
- depression
- dehydration
- stress
- skipping meals
What are cluster headaches?
- severe and unbearable unilateral headaches
- usually around the eye
- crescendo pain which may affect temples
Who is the typical patient to suffer from cluster headaches?
- 30-50 y/o male smoker
- attacks triggered by: alcohol, strong smells, exercise
What is the frequency of cluster headaches?
- attacks lasting 15 mins - 3hrs
- may suffer multiple attacks per day for weeks or months
- followed by pain free period lasting 1-2 years
What are the symptoms of cluster headaches?
- unilateral
- red, swollen, watering eye
- pupil constriction
- ptosis
- nasal discharge
- facial sweating
What are the types of migraines?
- migraine with or without aura
- silent migraine (with aura but without headache
- hemiplegic migraine
What are migraine triggers?
- stress
- bright lights
- strong smells
- dehydration
- menstruation
- abnormal sleep patterns
- certain foods e.g. chocolate, cheese, caffeine
What are the symptoms of migraine?
- pounding/throbbing
- usually unilateral
- photophobia and phonophobia
- nausea and vomiting
What is aura?
- visual changes
- sparks in vision
- blurring lines
- lines across vision
- loss of visual field
What is the treatment for migraine?
- paracetamol
- triptans e.g. sumatriptan
- NSAIDs
- antiemetics
How do triptans work?
- 5HT receptor agonists (serotonin)
- cause vasoconstriction in artery smooth muscle
- inhibit peripheral pain receptors
- reduce neuronal activity in CNS
What is prophylaxis for migraine?
- headache diary
- propanolol, topiramate, amitriptyline
- acupuncture
- riboflavin
What is epilepsy?
- an umbrella term for a condition where there is a tendency to have seizures
What is a seizure?
- a transient episode of electrical activity due to abnormally excessive or synchronous neuronal activity within the brain
What are the causes of seizures?
- vascular
- idiopathic
- infection
- trauma
- dementia and drugs
What are some seizure triggers?
- fatigue
- stress
- alcohol and drugs
- flashing lights
- monthly periods
- missing meals
- fever
What is the pathophysiology behind epileptic seizures?
- normal balance between GABA and glutamate
- balance shifts towards glutamate
- more excitatory > inc glutamate stimulation and inc GABA inhibition
How is epilepsy diagnosed?
- electroencephalogram: electrical activity in brain
- MRI brain
What is a generalised tonic-clonic seizure?
- loss of consciousness with muscle tensing (tonic) and muscle jerking (clonic) movements
- tonic phase occurs before clonic
- post-ictal period
- limb contraction, extension, back arching and - usually last 2-3 minutes
- ictal cry: sound resulting from chest contraction
What symptoms are experienced in the postictal period?
- amnesia
- postictal nose wiping (ipsilateral)
- confusion, irritability, feeling low
- sore tongue from bitten
What is an absence seizure?
- commonly in school aged children
- becomes blank and stares into space then abruptly returns to normal
- unaware of their surroundings and unresponsive but still conscious
- Episodes last 10-20 seconds and can disappear with age
What is the difference between tonic and atonic seizures?
- Tonic: person becomes stiff suddenly
- Atonic: known as drop attacks where all muscles relax at once (lapse in muscle tone). These don’t tend to last for more than 3 minutes
What is a myoclonic seizure?
- sudden, brief muscle contractions like a jump
- Seizures are brief but can occur in clusters, usually shortly after waking up
- Patient remains conscious.
What is a complex partial seizure?
- consciousness may be impaired
- Often occurs in the temporal lobe
- May have post-ictal confusion
What is a focal seizure?
- only one part of the brain is affected
- Can be aware or unaware
- start in the temporal lobes and can affect hearing, speech, memory and emotions.
- Presentation: hallucination, flashbacks, deja vu, doing things on autopilot.
What are the symptoms of focal aware (partial) temporal and frontal lobe seizures?
- Temporal: rising feeling in stomach, deja vu, unusual taste or smells, intense feelings of fear or joy
- Frontal: ‘wave feeling’ going through head, stiffness or twitching in a limb
What are the symptoms of focal aware (partial) parietal and occipital lobe seizures?
- Parietal: numbness or tingling, arms or legs feel bigger or smaller than normal
- Occipital: visual disturbance (coloured or flashing lights), hallucinations
How is epilepsy investigated?
- electroencephalogram (EEG) shows typical patterns
- MRI brain
What is the treatment for epilepsy?
- sodium valproate
- lamotrigine for child bearing aged women
- carbamazepine: 1st line for focal seizure
How does sodium valproate work and what are the side effects?
- increases activity of GABA: has relaxing effect
- inhibits sodium ion channels
- teratogenic, liver damage, hair loss, tremor
What is an ischaemic stroke?
- 85% cases
- a long TIA
- caused by thrombosis/AF embolisation
What is a haemorrhagic stroke?
- 15% cases
- ruptured blood vessel
- caused by trauma, htn, berry aneurysm rupture
What are general symptoms of an anterior circulation stroke?
- hemiparesis
- hemisensory loss
- visual field defect (homonymous hemianopia withOUT macular sparing)
What are symptoms of an anterior circulation dominant hemisphere stroke?
- usually in left hemisphere
- expressive and receptive dysphagia
- dyslexia
- dysgraphia
What are symptoms of an anterior circulation non-dominant hemisphere stroke?
- anosognosia
- visuospatial dysfunction: geographical agnosia, dressing and constructional apraxia
What are symptoms of a posterior circulation stroke?
- often affects cerebellum + occipital lobe
- clumsiness, difficulty walking in straight line
- visual disturbance
- slurred speech
- headache, vomiting
What investigations are done for stroke?
- 1st line: CT head
- gold: diffusion weighted MRI
- blood test
- carotid doppler
What is the management for stroke?
- aspirin 300mg stat and continued for 2 weeks
- thrombolysis with alteplase (TPA) in 4.5 hr window
- keep BP high to avoid reduced perfusion
What are the secondary prevention guidelines for stroke?
- Clopidogrel 75mg once daily
- Atorvastatin 80mg started (not immediately)
- Carotid endarterectomy or stenting
- Treat modifiable risk factors
What is subarachnoid haemorrhage?
- bleeding into subarachnoid space between Pia mater and arachnoid membrane (where CSF is)
- usually due to ruptured cerebral aneurysm
What are the symptoms of a subarachnoid haemorrhage?
- thunderclap headache described like being hit on the back of the head
- neck stiffness
- photophobia
- visual changes
- neurological symptoms
What are the causes of subarachnoid haemorrhage?
- cocaine use
- sickle cell anaemia
- connective tissue disorders
- neurofibromatosis
- autosomal dominant PKD
What is the presentation of brain tumours?
- varied dependent on tumour grade, site, type
- headache
- seizures
- focal neurological symptoms
- other non-focal symptoms e.g. cognitive problems or behavioural changes
What is the epidemiology of subarachnoid haemorrhage?
- black patients
- female
- age 45-70
What are risk factors for subarachnoid haemorrhage?
- htn
- smoking
- excess alcohol consumption
- cocaine use
- family history
How is a subarachnoid haemorrhage investigated?
- 1st line: NC CT head: hyperattenuation of blood in subarachnoid space
- If negative: LP for CSF. Raised red cell count and xanthochromia (bilirubin)
- If +ve: angiography
What is the management of subarachnoid haemorrhage?
- surgical intervention for aneurysms: endovascular coiling with catheter or clipping off
- nimodipine: CCB that prevents vasospasm
What are the symptoms of a raised ICP headache?
- woken by headache
- worse in the morning, lying down
- exacerbated by coughing, sneezing, drowsiness
- nausea and vomiting
What are symptoms of a brain tumour?
- raised ICP
- Cushing’s triad
- focal neurology
- epileptic seizures
- lethargy + weight loss
What is Cushing’s triad?
- bradycardia
- irregular respiration
- widened pulse pressure
What is the investigation for suspected brain tumour?
- MRI
- biopsy
- NO LP > contraindicated if high ICP
What are some types of primary brain tumour?
- astrocytoma
- oligodendrocytoma
- meningioma
- Schwannoma
Which cancers commonly metastasise to the brain?
- lung
- breast
- renal cell carcinoma
- melanoma
What are the types of gliomas?
- astrocytomas
- oligodendroglioma
- ependymoma
- grade 1 are benign
- grade 4 are most malignant: glioblastoma
What is the treatment for brain tumours?
- surgery: early resection
- combined radiotherapy and chemotherapy
What is an acoustic neuroma?
- tumours of Schwann cells on auditory nerve
- occur along cerebellopontine angle
- symptoms: hearing loss, tinnitus, balance problems
What is papilloedema?
- swelling of optic disc 2º to raised ICP
- blurring of optic disc margin
- Elevated optic disc
- Engorged retinal veins
- Creases in the retina and haemorrhages around optic disc
What are red flag features of headaches?
- Constant
- Nocturnal
- Worse on waking
- Worse on coughing, straining or bending forward
- Vomiting
What is motor neurone disease?
- progressive, ultimately fatal condition
- motor neurones stop functioning
What are the types of motor neurone disease?
- amyotrophic lateral sclerosis (ALS)
- progressive bulbar palsy
- progressive muscular atrophy
- primary lateral sclerosis
What is the pathophysiology behind motor neurone disease?
- progressive degeneration of upper and lower motor neurones
- sensory neurones spared
What are risk factors for motor neurone disease?
- genetic
- smoking
- SOD-1 mutation
- exposure to heavy metals and pesticides
What is the presentation of motor neurone disease?
- progressive weakness of muscles affecting limbs, trunk, face, speech
- weakness first noticed in upper limbs: fatigue when exercising
- dysarthria
- mixed LMN and UMN signs
What are signs of lower motor neurone disease?
- muscle wasting
- reduced tone
- fasciculations
- reduced reflexes
- Babinski -ve
What are the signs of upper motor neurone disease?
- increased tone or spasticity
- brisk reflexes
- no fasciculation
- babinski +ve: upgoing plantar responses
What are the medications used for tremors?
- primidone
- β blockers
- gabapentin
What is the management of motor neurone disease?
- riluzole: sodium channel blocker
- edaravone
- non-invasive ventilation to support breathing at night
What is a transient ischaemic attack (TIA)?
- transient neurological dysfunction secondary to ischaemia without infarction
- often precede a stroke
- caused by carotid thrombo-emboli
What is the management of TIA?
- 300mg aspirin as soon as suspected
- followed by clopidogrel
What is amaurosis fugax?
- sudden loss of vision in one eye: veiling
- caused by infarct in retinal arteries
- retinal branches from ophthalmic which branches from int carotid
What are the symptoms of a stroke in the anterior cerebral artery?
- weak, numb, contralateral leg
What are the symptoms of a stroke in the middle cerebral artery?
- weak, numb, contralateral side of the body
- facial drooping
- forehead sparing
- dysphasia (temporal lobe)
What are the symptoms of a stroke in the posterior cerebral artery?
- visual loss
- contralateral homonymous hemaniopia with macular sparing
What is the ABCD2 scoring system?
- risk of stroke following TIA
- Age >60 (1)
- BP > 140/90 (1)
- Clinical symptoms: unilateral weakness (2), slurred speech, no weakness (1)
- duration Sx: >1h (2). <1hr (1)
- T2DM (1)
What are symptoms of meningitis?
- fever
- photophobia
- neck stiffness
- non-blanching petechial rash
- vomiting
What is Kernig’s test?
- lie patient on back
- flexing one hip and knee to 90 degrees and slowly straighten knee (keep the hip flexed)
- spinal pain or resistance to movement in meningitis
What is Brudisinski’s test?
- lie patient on back
- gently lift head and neck and flex chin to chest
- patient will involuntarily flex hips and knees
What is the management of meningitis?
- Assess GCS
- Blood cultures
- Broad spectrum antibiotics
- steroids e.g. dexamethasone
What antibiotics are given for meningitis?
- IV benzylpenicillin in primary care and immediate hospital referral
- < 3mo: cefotaxime + amoxicillin
- > 3mo: ceftriaxone
What special considerations should be made when treating meningitis?
- allergy to penicillin: if anaphylaxis switch to chloramphenicol
- immunocompromised: potentially caused by listeria: add amoxicillin
- recent travel: add vancomycin
What are contraindications for a lumbar puncture?
- abnormal clotting (platelets/coagulation)
- petechial rash
- raised ICP
What are differential diagnoses for meningitis?
- subarachnoid haemorrhage
- migraine
- flu and sinusitis
- malaria
What is the public health response to meningitis?
- notify UK HSA
- identify close contacts
- PEP: ciprofloxacin or rifampicin for close contacts
What is meningitis?
- inflammation of the meninges (lining of the brain and spinal cord)
What are the causes of meningitis?
- infective: bacterial, viral, fungal, parasitic
- non-infective: paraneoplastic, drugs, autoimmune
How does bacteria causing meningitis enter the body?
- extra cranial infection: nasal carriage, otitis media, sinusitis
- via bloodstream: bacteraemic
- neurosurgical complications: post op, infected shunts
What is meningococcal septicaemia?
- meningococcus bacterial infection in the bloodstream
- causes the non blanching rash
- infection has caused disseminated intravascular coagulopathy (DIC) and subcutaneous haemorrhages
Which bacteria commonly cause meningitis?
- Neisseria meningitidis (gram -ve diplococcus)
- Strep pneumoniae (gram +ve cocci)
- listeria monocytogenes (pregnancy)
- group B strep in neonates
What are the most common causes of viral meningitis?
- HSV, enterovirus and VZV
- CSF sample sent for PCR testing
- treated with aciclovir
What are the possible complications of meningitis?
- hearing loss
- cerebral palsy
- seizures and epilepsy
- cognitive impairment
- disability
What is the definition and presentation of encephalitis?
- inflammation of the brain
- flu-like illness
- altered GCS, fever, seizures, memory loss
What are the causes of encephalitis?
- usually viral
- herpes simplex
- varicella zoster
What are the investigations for encephalitis?
- MRI head
- LP: lymphocytic CSF and viral PCR
What is the management of encephalitis?
- supportive
- aciclovir if HSV or VZV
What is cauda equina syndrome?
- nerve roots of cauda equina at bottom of spine are compressed
- emergency
What is the anatomy of the cauda equina?
- collection of nerve roots travelling through spinal canal after cord terminates around L2/L3
- spinal cord tapers down into conus medullaris
- nerve roots exit at vertebral level
What do the nerves of the cauda equina supply?
- sensation to lower limbs, perineum, bladder, rectum
- motor innervation to lower limbs, anal and urethral sphincters
- parasympathetic innervation of bladder and rectum
What is the aetiology of cauda equina syndrome?
- herniated disc (most common)
- (metastasised) tumours
- spondylolisthesis
- abscess and trauma
What are signs of cauda equina syndrome?
- saddle anaesthesia
- loss of sensation in bladder and rectum
- faecal incontinence
- bilateral sciatica and motor weakness
What is the management of cauda equina?
- emergency MRI and neurosurgical input to consider lumbar decompression surgery
What are the causes of spinal cord compression?
- degenerative disc lesions
- degenerative vertebral lesions
- TB
- vertebral neoplasms
- epidural abscess or haemorrhage
What is the presentation of spinal cord compression?
- sensory loss below level of compression
- spastic paraparesis/tetraparesis
- radicular pain at level of compression
Where is the sciatic nerve and what does it do?
- L4-S3 form sciatic nerve
- supplies sensation to lateral lower leg and foot
- motor for posterior thigh, lower leg and foot
What is sciatica?
- unilateral pain from the buttock radiating down the back of the thigh to below the knee or foot
- causes: herniated disc, spondylolisthesis, spinal stenosis
What is the presentation of sciatica?
- electric or shooting pain
- paraesthesia
- numbness
- motor weakness
What is dementia?
- progressive global decline of cognitive function without impairment of consciousness
- mild cognitive impairment (MCI) is seen as a pre-cursor
- typically affects temporal and parietal lobes
What is vascular dementia?
- results from many small infarcts
- step-wise progression
- infarcts affect function if damaging white matter
How can vascular dementia be prevented and which conditions is it associated with?
- aspirin or warfarin therapy
- controlling BP
- raised BP, past strokes
What is Lewy-body dementia?
- presence of Lewy bodies in the brainstem and neocortex
- fluctuating cognitive impairment
- hallucinations and Parkinsonism
What are the causes of peripheral neuropathy?
- Diabetes
- Alcoholism
- Vitamin (B12) deficiency
- Infective/inherited
- Drugs
What is the pathophysiology behind peripheral neuropathy (6 mechanisms)?
- demyelination (Schwann cell damage)
- axonal degeneration
- nerve fibres cut or crushed
- compression causing demyelination
- infarction
- infiltration by infection
What are the aetiologies of secondary intracerebral haemorrhages?
- clotting disorder
- AV malformation
- brain tumour
- intracranial aneurysm
- trauma
What are the classic cerebellar signs (DANISH)?
- D: dysdiadochokinesia
- A: ataxia
- N: nystagmus
- I: intentional tremor
- S: slurred speech
- H: hypotonia
What is Charcot-Marie-Tooth disease?
- autosomal dominant disease affecting peripheral motor and sensory nerves
- cause dysfunction in myelin and axons
What are classical presentations of Charcot-Marie-Tooth disease?
- high foot arches (pes cavus)
- distal muscle wasting (stork calves)
- lower leg and hand weakness
- reduced tendon reflexes and sensory tone
What are the causes of peripheral neuropathy?
- Alcohol
- B12 deficiency
- Cancer and CKD
- Diabetes and drugs (isoniazid, amiodarone and cisplatin)
- Every vasculitis
How is Duchenne’s muscular dystrophy passed down and who does it affect?
- X-linked recessive mutation
- boys affected exclusively
What is the pathophysiology and presentation of Duchenne’s muscular dystrophy?
- muscle is replaced with adipose tissue
- causes difficulty getting up from lying down
- skeletal deformities: scoliosis, hyperlordosis
What is carpal tunnel syndrome?
- compression of the medial nerve as it travels through the wrist
What is the anatomy of the carpal tunnel?
- between the carpal bones and flexor retinaculum
- flexor retinaculum: runs across palmar side of wrist
- median nerve and flexor tendons travel through
Which muscles does the median nerve provide motor function to and which branch is it?
- abductor pollicis brevis
- opponens pollicis
- flexor pollicis brevis
- palmar digital cutaneous branch
What does the palmar cutaneous branch innervate?
- sensory to palm
- thumb
- index and middle finger
- lateral half of ring finger
What are the risk factors for carpal tunnel syndrome?
- repetitive strain
- obesity
- perimenopause
- RA
- diabetes
How does carpal tunnel syndrome present?
- worse at night
- sensory symptoms: numbness, paraesthesia, burning, pain
- weakness of thumb movements, grip strength, difficulty with fine movement, wasting of thenar muscles
What is Phalen’s test?
- fully flexing the wrist and holding it there
- wrists bent inwards at 90º
- triggers numbness and parasthesia
What is Tinel’s test?
- tapping the wrist where the median nerve meets the carpal tunnel
- triggers numbness and parasthesia
What other investigations are done for carpal tunnel syndrome?
- nerve conduction studies
- carpal tunnel questionnaire
How is carpal tunnel syndrome managed?
- rest and altered activities
- wrist splints
- steroid injections
- surgery: flexor retinaculum cut to relieve pressure
What occurs in the frontal lobe?
- voluntary and planned motor behaviours
- motor speech area (Broca’s)
- personality
- planning
What is the function of the temporal lobe?
- hearing
- language comprehension
- semantic knowledge
- memory
- emotional behaviour
What is Alzheimer’s disease?
- leading cause of dementia
- progressive neurodegenerative disorder causing deterioration in mental performance
- general atrophy of brain
- frontal and temporal lobes affected in particular
What is the presentation of Alzheimer’s?
- temporal: episodic memory disorder
- parietal: visuospatial difficulties
- receptive and expressive dysphagia
- emotional disorder/psychosis
- problems with planning and problem solving
- early loss of language (subtle)
What is the pathophysiology of Alzheimer’s disease?
- accumulation of β-amyloid peptides > plaques
- degrades amyloid precursor protein
- leads to neuronal damage, neurofibrillary tangles, amyloid plaques
- loss of Ach
Which areas of the brain are most affected by Alzheimer’s?
- hippocampus
- amygdala
- temporal neocortex
- subcortical nuclei
What are the risk factors for Alzheimer’s?
- 1st degree relative
- Down’s
- depression/loneliness
- decreased exercise, physical activity
What are β-amyloid plaques?
- excess deposition of β-amyloid
- amyloid precursor protein broken down (found in cell membrane of neurones)
- accumulate between synapses and affect nerve transmission
- cause localised inflammation
What is the management of dementia?
- AChE inhibitors: donepezil: inc cholinergic transmission in brain
- NMDA antagonists: inhibits glutamate receptors
- antipsychotics
What is fronto-temporal dementia?
- frontal and temporal lobe atrophy: loss of spindle neurones
- behaviour change
- disinhibition and emotional unconcern
How is dementia investigated?
- CT/MRI to look for lesions/atrophy
- bloods
- questionnaires: 6 CIT
What is syncope?
- temporarily losing consciousness
- due to disruption of blood flow to brain
- also called vasovagal episodes or fainting
What is the presentation of syncope?
- hot and clammy, sweaty
- heavy
- dizzy, lightheaded
- vision going dark
What are the primary causes of syncope?
- dehydration
- missed meals
- extended standing
- vasovagal response to stimuli: surprise, pain
What are the secondary causes of syncope?
- hypoglycaemia
- dehydration
- anaemia
- infection
- anaphylaxis
- arrhythmia
What investigations are done for syncope?
- ECG/24 hr ECG
- echocardiogram
- bloods: FBC, electrolytes, blood glucose
What are some causes of lower motor neurone injury?
- MND, spinal muscular atrophy, polio
- Guillain Barre
- neuropathies
- myasthenia gravis
- myositis
What is the presentation of spinal muscular atrophy?
- symmetrical, proximal muscle weakness caused by loss of motor neurons
- lower limbs more affected than upper
- affects bulbar function and breathing
Describe SMA 1 and 2
- SMA 1: onset in first few months, death within 2 years
- SMA 2: onset in 18 months, never walk but survive to adulthood
Describe SMA 3 and 4
- SMA 3: onset after 1y/o, walk but later lose ability, resp affected
- SMA 4: onset in 20s, ability to walk for short distances, everyday tasks > fatigue. resp + life expectancy not affected
What is the pathophysiology behind neuropathies?
- primary demyelination > secondary axonal degeneration
- primary axonal degeneration > secondary demyelination
What are the types of peripheral neuropathies?
- mononeuropathy: one nerve
- mononeuropathy multiplex: several nerves, no pattern
- polyneuropathy: many nerves (distal + symmetrical)
What is Lambert Eaton syndrome?
- autoimmunity against presynaptic Ca channels in NMJ
- symptoms improve with exertion
- associated with small cell lung carcinoma
- symptoms start with extremities
What is the presentation of Lambert Eaton syndrome?
- proximal muscle weakness
- diplopia
- ptosis
- dysphagia
What is the treatment of Lambert Eaton syndrome?
- Amifampridine
- immunosuppressants: prednisolone
How can you differentiate between UMN and LMN lesions?
- forehead spared in UMN
- ask patient to raise eyebrows
- if can move both sides then UMN lesion
- if one side affected then LMN lesion
What is the presentation of a radial nerve palsy and what are the nerve roots?
- roots C5-T1
- wrist drop
- innervates extensor muscles
What is the presentation of a ulnar nerve palsy and what are the nerve roots?
- roots C8 + T1
- claw hand (4th and 5th fingers)
What are differential diagnoses for epilepsy?
- syncope
- cardiac arrhythmia
- panic attack
- non-epileptic + dissociative seizures
- TIA
- migraine
What is Brown-Sequard syndrome?
- hemisection of the spinal cord
- involves anterolateral system and DCML pathway
- symptoms occur below the lesion
What are the symptoms of Brown-Sequard?
- contralateral loss of pain and temperature
- ipsilateral loss of proprioception and vibration
- ipsilateral UMN weakness below lesion
Describe GCS?
- Eyes, verbal response, motor response
- max score is 15, min is 3
- 8/15 or below: secure airway