Demyelination- MS Flashcards
what is MS?
a chronic and progressive condition characterised by demyelination of neurons in CNS, where lesions are seen disseminated in time and space
Pathophysiology?
thought to be caused by an inflammatory process involving immune destruction of myelin sheath
Epidemiology?
- females > males
- aged 20-40
Aetiolgy?
- genes
- EBV
- smoking
- obesity
- Vit D deficiency
Presentation?
- Optic Neuritis - most common presentation
- Cr.N 6 involvement
- diploplia
- interneuclear opthalmoplegia
- conjugate lateral gaze disorder
- focal weakness
- focal sensory weakness
- ataxia
- sensory
- cerebellar
What is optic neuritis and what are the key features? mnemonic
Unilateral reduced vision due to demyelination in the optic nerve, presents over hours to days
features:
- Pale disc/ Pain on eye movement
- Loss of visual acuity / Loss of colour vision (red)
- Afferent pupillary defect
- Central scotoma - enlarged blind spot
what should be done in acute loss of vision?
referred urgently to opthalmologist, should be treated w steroids. Takes 2-6 weeks to recover
What are some presentations of focal weakness?
- bell’s palsy
- Horner’s syndrome
- limb paralysis
- incontinence
What are some presentations of focal sensory weakness?
- trigeminal neuralgia
- numbness
- paraesthesiae
- Lhermitte’s sign
What is Lhermitte’s sign?
Electrical shock sensation travelling down spine and to limbs upon forward flexion of neck. Indicates disease in cervical spine.
What is ataxia?
Problem with co-ordinated movement.
(many symptoms mimic those of being drunk- slurred speech, loss of coordination, stumbling, falling)
What is the issue in sensory ataxia? Test ?
Loss of proprioceptive sense.
- positive Romburg’s test
- can cause pseudoathetosis
Disease pattern?
- Clinically isolated syndrome
- can never happen again or progress to MS. If lesions are spotted on MRI, v likely it will progress to MS.
- Relapsing-Remitting
- most common pattern at initial diagnosis.
- Secondary progressive
- after initially presenting as relapsing-remitting, symptoms gradually worsen with incomplete remission. Symptoms become more and more permanent.
- Primary progressive
- symptoms gradually worsen from initial diagnosis with no relapsing-remitting course
Diagnosis?
clinical diagnosis- based on symptoms and clinical picture
Ix:
- MRI- demyelinating lesions
- LP- oligoclonal bands in CSF
how long do symptoms have to be present for to diagnose primary progressive MS?
symptoms have to be progressive for at least 1 year
