Multiple Sclerosis Flashcards
What is multiple sclerosis?
It is a a chronic and progressive autoimmune condition that involves demyelination of the central nervous system
What is myelin?
It is the sheath that covers the axons of neurones in the central nervous system
What is the function of myelin?
It allows quick transmission of electrical impulses between neurones
What cells produce myelin in the peripheral nervous system?
Schwann cells
What cells produce myelin in the central nervous system?
Oligodendrocytes
What is the pathophysiological cause of multiple sclerosis?
There is inflammation around the myelin sheath, which results in the infiltration of immune T-cells that then cause damage
This affects the transmission of electrical signals along the nerve
What hypersensitivity reaction occurs in multiple sclerosis?
Type IV
Which nervous system is affected in multiple sclerosis - central or peripheral?
CNS
What are the four classifications of multiple sclerosis?
Clinically Isolated Syndrome (CIS)
Relapsing Remitting MS (RRMS)
Secondary Progressive MS (SPMS)
Primary Progressive MS (PPMS)
What is clinically isolated syndrome?
It refers to the first, single episode of demyelination, resulting in neurological clinical features that persist for a period greater than 24 hours
Why does clinically isolated syndrome not obtain in a diagnosis of multiple sclerosis?
This is due to the fact that the lesions have not ‘disseminated in time and space.’
Does clinically isolated syndrome result in multiple sclerosis?
These individuals may or may not go on to develop multiple sclerosis
What clinically isolated syndrome feature estimates a higher risk of multiple sclerosis development?
There are features of multiple sclerosis on MRI scans
What is the most common classification of multiple sclerosis at initial diagnosis?
Relapsing remitting multiple sclerosis (RRMS)
What is RRMS?
It is characterised by relapsing episodes of disease followed by periods of remission
Describe the cycle associated with RRMS
During the relapsing episodes, clinical features usually have a gradual onset over a few days, which then stabilise to persistent clinical features for a period of days to months
There is then a period of remission of varying duration
In what two ways can RRMS be classified?
Disease activity (active/non-active)
Disease progression (worsening/non-worsening)
What does active disease refer to?
The development of new clinical features or the appearance of new lesions on MRI
What does worsening disease refer to?
The overall worsening of disability from initial diagnosis
What is SPMS?
It is characterised as initial relapsing-remitting disease that has progressed into a state of incomplete remission with worsening clinical features
In what two ways can SPMS be classified?
Disease activity (active/non-active)
Disease progression (progressing/non-progressing)
What does progressing disease refer to?
The the overall worsening of disease over time (regardless of relapses)
What is PPMS?
It is characterised by continuous worsening of disease from initial diagnosis without remission periods
Which age group tend to be affected by PPMS?
> 50 yrs old
In what two ways can PPMS be classified?
Disease activity (active/non-active)
Disease progression (progressing/non-progressing)
What is different about multiple sclerosis classifications compared to other condition classifications?
These classifications are not separate conditions, and instead should be thought of as a spectrum of disease activity
What are the seven risk factors of multiple sclerosis?
Female Gender
Young Age (20-40 Years Old)
Family History
Smoking
Obesity
Epstein Barr Virus (EBV)
Reduced Vitamin D Exposure
What are the eighteen clinical features of multiple sclerosis?
Optic Neuritis
Sixth Cranial Nerve Palsy
Diplopia
Paraesthesia
Numbness
Trigeminal Neuralgia
Bell’s Palsy
Horner’s Syndrome
Lhermitte’s Sign
Hoffman’s Sign
Intention Tremor
Muscle Spasticity
Erectile Dysfunction
Urinary Incontinence
Urinary Retention
Vertigo
Ataxia
Lethargy
What is the most common clinical feature of multiple sclerosis?
Optic neuritis
What is optic neuritis?
It refers to demyelination and inflammation of the optic nerve
What are the eight causes of optic neuritis?
Multiple sclerosis
Diabetes
Syphillis
Sarcoidosis
SLE
Measles
Mumps
Lyme’s disease
What is the most common cause of optic neuritis?
Multiple sclerosis
What are the five clinical features associated with optic neuritis?
Unilateral Central Vision Loss
Colour Vision Impairment
Painful Eye Movements
Relative Afferent Pupillary Defect (RAPD)
Central Scotoma
What colour vision impairment is associated with multiple sclerosis?
Red desaturation
What is red desaturation?
It involves patients visualising red objects as pink
What is RAPD?
It is a condition in which pupils respond differently to light stimuli shone in one eye at a time
Specifically, when shining light into one eye, both pupils should constrict
This constriction should remain when the light is then shone into the other eye
However, in RAPD, when the light is then shone into the other eye, dilatation occurs
What is central scotoma?
It refers to an enlarged blind spot
What two investigations are used to diagnose optic neuritis?
Fundoscopy
MRI of Brain & Orbits With Contrast
What are the two signs of optic neuritis on fundoscopy?
Optic disc swelling, or in severe cases optic disc atrophy
RAPD