Multiple Sclerosis Flashcards
(37 cards)
What is multiple sclerosis?
Inflammatory condition of the nervous system causing demyelination of the nerves in the CNS
What is the pattern of MS?
Focal disturbance of the the function of nerves occurs in episodes and follows a relapsing remitting occur.
Episode of demyelination —> malfunction —> remission (pattern and episodes are different for everyone)
How does demyelination occur?
- Auto-immune process
- Activated T cells cross blood brain barrier
- Acute inflammation of myelin sheath
What occurs after the episode of demyelination?
Post-inflammatory gliosis -> functional deficit
What is gliosis?
Reactive change (proliferation or hypertrophy) of glial cells in response to damage to the central nervous system (CNS)
What does MS look like on an MRI scan?
Lesions and plaques (white blobs)
Axonal loss appears as black holes (in progressive disease)
Is an MRI scan diagnostic of MS?
No, as blobs can present in old age - need to diagnose it clinically
What does axonal loss lead to?
Disease progression and development of persistent disability
What is the aetiology of MS?
- Genetic inheritance
- Association with autoimmune disease
- Female
More prevalent the further away from the equator
At what age does MS usually present?
20s and 30s
What are the symptoms of relapse?
- Optic neuritis
- Sensory - i.e. numbness
- Limb weakness
- Brainstem diplopia/Vertigo/Ataxia-
- Spinal cord - bilateral symptoms and signs +/- bladder
What are the symptoms of optic/retrobulbar neuritis?
- Subacute visual loss
- Pain on moving eye
- Colour vision disturbed
- Usually resolves over weeks
- Initial swelling optic disc
- Optic atrophy seen later
- Relative afferent pupillary defect
What is reflective afferent pupillary defect?
Demyelination in optic nerves, pupil doesn’t constrict as quickly as it should -> shown when shining light on eye
What are eight differential diagnosis’ of optic neuritis?
- Neuromyelitis optica
- Sarcoidosis
- Ischaemic optic neuropathy
- Toxic/ drugs/ B12 deficiency
- Wegeners granulomatosis
- Local compression
- Lebers hereditary optic neuropathy
- Infection-borrelia
What are the symptoms of brainstem relapse of MS?
- Pons is susceptible to demyelination - internuclear ophthalmoplegia
- Cerebellum - vertigo, nyastagmus, ataxia
What is myelitis?
Inflammation of myelin sheath
• Partial or transverse (complete)
• Hyperaesthesia (heightened sensitivity)
What is the differential diagnosis of myelitis?
• Inflammation due to: - Neuromyelitis optica - SLE - sarcoidosis • Infection or post infection - (HIV, HTLV, HSV, TB, borrelia, mycoplasma etc) • Tumour • Paraneoplastic process • Stroke
What is Clinically Isolated Syndrome (CIS)?
One off episode of demyelination
For MS to be diagnosed there must be further episode -> second episode occurring in a different part of the CNS
What is the clinical definition of MS?
Episodes of demyelination disseminated in space and time
What are the symptoms of the progressive phase of MS?
- Fatigue, temperature sensitivity
- Sensory
- Stiffness or spasms
- Balance, slurred speech
- Swallowing
- Bladder + bowel
- Diplopia/ oscillopsia/ visual loss
- Cognitive-dementia/ emotional lability
How is MS diagnosed?
Clinical or MRI based:
• Posers criteria (clinical)
• Macdonald criteria (MRI) - shows new areas of demyelination
What are lesions or plaques on an MRI?
Areas of demyelination - can show more inflammation areas than episode patient experiencing (scan and patient symptoms don’t often correlate)
How do MRI scans show new areas of demyelination?
- Initial scan and then one 3 month later
* With and without use of gadolinium - new areas take gadolinium up
What are other investigations used?
- Lumbar puncture - presence of oligoclonal bands in CSF but not serum
- Visual/somatosensory evoked
- Bloods - exclude other inflammatory conditions
- CXR (rule of sarcoidosis)
