Neuro Questions Flashcards
what is multiple sclerosis?
- chronic autoimmune demyelinating disease of the CNS
- results in degeneration of axons in the brain and spinal cord
What are the 3 different classifications of MS
- relapsing-remitting MS → 90%
- Primary progressive MS → 10%
- Secondary progressive MS → RR-MS that becomes progressive
What are modifiable risk factors for MS?
- smoking
- vitamin D def
- obesity at a young age
- EBV infection
What is the pathophysiology of MS?
Broadly: autoimmune reaction results in inflammation within the CNS causing demyelination and axonal degeneration
- autoreactive T cells → inflammation and focal demyelinations of axons (acute plaques) → loss of axons and atrophy of oligodendrocytes (chronic plaques) → inadequate remyelination
What is Ihermitte sign?
- Shooting sensation down the spine on flexion of the neck
what are signs of MS on examination?
- INO → ipsilateral medial rectus weakness, disconjugate lateral gaze, nystagmus in contralateral eye
- Spinal cord tract demyelination signs
- spasticity, +ve babinskis, hyperreflexia,
- loss of senosory modalities
- senosry ataxia
- cerebellar lesion signs (charcot triad)
- nystagmus
- intention tremour
- scanning speech
- Cranial nerve palsies
- autonomic dysfunction
- lhermitte sign
- shooting sensation down the spine on flexion of the neck
What are symptoms of MS?
- fatigue
- Headache
- optic neuritis
- depression
- memory deficits
What are the symptoms of optic neuritis?
impaired vision and colour blindness, usually unilateral, may be associated with pain
What is Uhthoff phenomenon?
- reversible exacerbation of neurological symptoms following increase in body temperature
- after bath or shower, physical exertion, fever
what are DDx for MS?
- peripheral neuropathy → sensation and reflexes in limbs
- ischaemic stroke
- fibromyalgis
- other causes of spinal cord dysfunction → cervical spondylosis, transverse myelitis
- other autoimmune demyelinating disorders → guillain barre syndrome, Neuromyelitis optica spectrum disorders
What are the two categories of clinical features that are used to diagnose MS?
- Disseminated in TIME (DIT)
- appearence of new lesions over time
- associated new exacerbations
- Disseminated in SPACE (DIS)
- presence of lesions in different regions of the CNS
What is the investigation of choice for MS diagnosis and what are the findings on this test?
- MRI brain and spine
- MS plaques
- located in periventricular white matter with finger like projections
- hypointense in T1 MRI
- Hyperintense in T2 MRI
- MS plaques
- LP and CSF examination
- lymphocytosis
- increased myelin basic protein
- presence of oligoclonal bands of igG in CSF
how do you treat acute exacerbations of MS?
- high dose corticosteroid therapy
2. plasmapheresis → basically removes plasma (containing Autoantibodies) and replaces it with colloid fluid
what drugs are used to reduce frequency of exacerbations?
- DMARDS
- interferon beta
- monoclonal antibodies etc
what are 4 sequelae of MS?
- autonomic dysfunction → ED, Urinary retention, increased UTI risk
- osteopaenia/osteoporosis
- visual impairment
- depression
What is guillian barre syndrome?
- acute postinfectious polyneuropathy
- characterised by symmetric ascending flaccid paralysis
- due to cross reactive autoantibodies targeting the peripheral axons and causing demyelination
What are commonly associated pathogens causing GBS?
- bacteria → C.jejuni = most common
- Viruses → Zika, CMV, EBV, HIV, Influenza , SARS- CoV-2
- some reports post immunisation
What is the pathophysiology of GBS?
- cross-reactive autoantibodies are generated due to molecular mimicry → react with schwann cell antigens → immune mediated segmental demyelination → axonal degeneration in peripheral and cranial nerves
What are the signs of GBS on examination?
LMN signs
- bilateral flaccid paralysis → in glove and stocking dist.
- reduced or absent reflexes
- autonomic dysfunction
- arrhythmia, BP derangement, bladder/bowel issues
- cranial nerve involvement
- typically VII (diplegia of facial muscles), IX, X
- respiratory failure due to respiratory muscles paralysis
what are DDx for a peripheral neuropathy?
- Diabetic neuropathy → DM diagnosis
- myasthenia gravis → reflexes preserved, sensory features and autonomic dysfunction absent
- transverse myelitis → UMN signs present
- botulism
What are 6 investigations for GBS?
- ECG → autonomic dysregulation can give cardiac abnormalities
- Spirometry → resp failure monitoring
- Serology → Igs against schwann cells, pathogens causing disease
- Electroneurography → decreased nerve conduction velocity due to demyelination
- electromyography → signs of denervation, pathologic spontaneous activity
- LP and CSF analysis → raised protein levels, normal WBC
What is the difference between electroneurography and electromyography?
Electroneurography
- An analysis of a muscle’s electrical activity in response to stimulation of its supplying nerve.
- measured nerves conduction velocity, amplitude etc
Electromyography
- A diagnostic procedure in which the muscle activity in response to neural stimulation is measured to detect dysfunction at the level of the neuromuscular junction, the muscle, or the corresponding nerve.
what is the three step approach to management in GBS?
- supportive care → preventing complications of immobility, monitoring for cardiorespiratory function, ICU if indicated
- IV immunoglobulin
- Plasmapheresis
What is the pharmaco-management for status epilepticus?
- IV benzodiazepines or IM/Buccal if necessary
- midazolam, diazepam, clonazepam
- antiepileptics
- phenytoin
- valproate
- levetiracetam
- anaesthetic inducers if additional required
- ketamine
What are the supportive care techniques for seizure management?
- ABCDE assessment → CPR if necessary
- remove or control hazards
- place patient in recovery position
- if available (ie occurs at hospital) conduct Ix to determine cause
- VBG, BGL, FBC, UECs
- identify reversible causes of acute symptomatic seizure and treat accordingly
What are 5 classical triggers of seizure in people with epilepsy?
- sleep deprivation
- alcohol, drugs, and medications
- hormonal changes especially associated with menstruation and menopause
- physical exertion
- flashing lights
- Fever → febrile seizures
What are 6 causes of acute seizure (non-epilepsy)
- Brain injury
- Stroke
- CNS infections
- Electrolyte imbalances
- Drugs and alcohol use
- Drug and alcohol withdrawal
