Multiple Sclerosis Flashcards
What would the presentation be with someone with optic neuritis?
history of pain in the eye and blurred vision
- reduced colour vision (Ishihara chart)
- reduced pupillary light responses (RAPD)
- hole in visual field (scotoma)
What is the Ishihara chart?
it is a form of colour vision deficiency test that is used in diagnosing colour blindness
What is RAPD?
relative afferent pupillary defect
the pupils respond differently to light stimuli shone in one eye at a time
this is due to unilateral or asymmetrical disease of the retina or optic nerve
what is meant by scotoma?
an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity
this is surrounded by a field of normal vision
What is optic neuritis?
inflammation of the optic nerve
this causes pain and loss of vision
Why is optic neuritis frequently not visible?
it affects the retrobulbar space
this is the area located behind the globe of the eye
What is the prognosis of optic neuritis like?
What can speed up rate of recovery?
good prognosis as 95% return to visual acuity of 6/12 or greater within 12 months
high dose steroids speed up rate of recovery but have no effect on final acuity
how is optic neuritis related to MS?
50% of cases go on to develop MS within 10 years
What are some of the presenting signs and symptoms of transverse myelitis?
- tingly numbness starting in both feet and gradually ascending to level around the chest
- unsteady walking and fatigued easily
- electric shock sensation running down body whenever patient bends head
What is transverse myelitis?
inflammation inside the spinal cord in one section
it damages the myelin covering nerve cell fibres and interrupts messages sent from spinal cord nerves throughout the body
What type of sensation tends to be affected in transverse myelitis?
it is often purely sensory
it may affect the bladder
What is Lhermittes phenomenon in transverse myelitis?
an electric shock-like sensation that occurs on flexion of the neck
the sensation radiates down the spine, often into the legs, arms and sometimes to the trunk
How is transverse myelitis related to MS?
50% of patients go on to develop multiple sclerosis
What is involved in diagnosing MS?
clinical diagnosis
relies on dissemination in time and place
the Macdonald criteria is used
What is meant by clinically definite MS?
optic neuritis and transverse myelitis at different times
What is involved in diagnosing not definite MS?
- clinically isolated syndrome (CIS)
- myelitis and optic neuritis at the same time
- recurrent myelitis
- recurrent or sequential optic neuritis
How are cases with optic neuritis and transverse myelitis treated?
intravenous methylprednisolone 1 g daily for 3 days
What is meant by ‘relapsing-remitting multiple sclerosis’?
the patient has attacks where their symptoms flare up
an attack is followed by a time of recovery where the patient has few or no symptoms (this is remission)
What is a treatment for relapsing-remitting multiple sclerosis?
dimethyl fumarate
240mg twice daily
this condition usually starts in 20-30s
Why is MS so prominent?
it is the most common cause of neurological disability in young adults in the UK
What sex, ages and ethnicity are more susceptible to MS?
sex ratio is 2 female : 1 male
most common age of onset is 30-40 years
most prevalent in northern europeans, US caucasians and canadians
What system is affected by MS?
What does this lead to?
it is a disease of the central nervous system (CNS)
an inflammatory reaction in the CNS causes loss of myelin and slowing of nerve conduction
there are areas of demyelination and loss of axons
What are the 2 possible mechanisms of demyelination?
- immune mediated injury
- antibody mediated injury
In immune mediated injury, how can T cells cause demyelination?
- T cells become activated and enter the CNS through blood vessels
once inside the CNS, T cells release chemicals that cause inflammation and damage and result in damage to myelin
- T regulatory cells do not function correctly and do not effectively turn off inflammation
- cytotoxic T cells directly attack and destroy cells bearing certain characteristics
