Multiple Sclerosis Flashcards
Where does multiple sclerosis affect?
White matter, the central nervous system - it doesn’t affect the peripheral nerves
What is the disease mechanism of MS?
Activated T cells cross the blood brain barrier causing demyelination - acute inflammation of myelin sheath - loss of function - post inflammatory gliosis
What is meant by gliosis?
Reactive change of glial cells in response to damage to central nervous system - in most cases it involves proliferation or hypertrophy of several different types of glial cells including astrocytes, microglia and oligodendrocytes.
(proliferation and hypertrophy of glial cells after damage to the CNS)
What is seen on MRI of MS patients?
Lesions or plaques
Axonal loss is seen as black holes on MRI - later seen as cerebral atrophy
Where is MS rare?
Rare in indigenous population of africa and australasia
What is the pathogenesis of MS?
Complex genetic inheritance - association with autoimmune disease
What percent of MS cases present with a relapse?
80%
What are the likely features of relapse?
Optic neuritis
Sensory symptoms
Limb weakness
Brainstem diplopia/vertigo/ataxia
Spinal cord - bilateral symptoms and signs +/- bladder
Ataxia: Loss of full control of body movements
What is the presentation of optic neuritis?
Subacute visual loss
Pain on moving eye
Distorted colour vision
Initial swelling of optic disk
Optic atrophy is seen later
Relative afferent pupillary defect (pupil dilates when light shines)
What is the differential diagnosis for optic neuritis?
- Neuromyelitis optica
- Sarcoidosis
- Ischaemic optic neuropathy
- Toxic/ drugs/ B12 deficiency
- Wegeners granulomatosis
- Local compression
- Lebers hereditary optic neuropathy
What is the result of brainstem relapse?
Cranial nerve involvement
Pons - internuclear ophthalmoplegia - ophthalmoplegia is paralysis of muscles within or surrounding the eye
vertigo, nystagmus, ataxia, diploplia
Define myelitis
Inflammation of the spinal cord
Define transverse myelitis
Inflammation of the spinal cord
Inflammation results in damage to the nerve cells and loss of their myelin sheath leading to reduced conductivity
Transverse implies that the inflammation extends across the entire width of the spinal cord
What are the common features of transverse myelitis
What are the common features of transverse myelitis (complete myelitis)?
Weakness in arms and legs
Pain
Sensory alterations
Bowel and bladder dysfunction
What is the diagnosis of MS?
•MS=episodes of demyelination disseminated in space and time
May be clinical or MRI based diagnosis
Posers criteria
Macdonald criteria
When might further relapses occur?
Within months or years of first relapse
What signs and symptoms do MS patients accumulate?
Fatigue
Temperature sensitivity
Sensory
Stiffness of spasms
Balance, slurred speech
Swallowing
Bladder and bowel
Diplopia, oscillopsia, visual loss
Cognitive - demential / emotional liability
Oscillopsia is a visual disturbance in which objects in the visual field appear to oscillate
What are the things to look for on examination of a patient with suspected MS?
–Afferent pupillary defect
–Nystagmus or abnormal eye movements
–Cerebellar signs
–Sensory signs
–Weakness
–Spasticity
–Hyperreflexia
–Plantars extensor
For every 10 lesions seen on MRI, how many relapses are expected?
1 - scans and patient symptoms and signs often do not correlate
What do white spots indicate on an MRI?
Not necessarily MS - White spots are common in smokers and hypertensives
What indicator is used in MRI?
Gadolinium - indicates acute inflammation
What are other investigations for MS?
Lumbar puncture - oligoclonal bands present in CSF but not serum - Oligoclonal bands – sign of inflammation in the CNS – should only be found in CNS and not in the blood, MS is isolated to the CNS. Bands in CNS and serum just means widespread inflammation.
Bloods - exclude other inflammatory conditions
Chest X-ray
Visual/Somatosensory evoked response
What is the differential diagnosis for MS?
Acute disseminating encephalomyelitis
Other autoimmune disease - SLE
Sarcoidosis
Vasculitis
Infection such as limes disease, HTLV - 1
What are the types of MS?
Relapsing remitting
Secondary progressive
Primary progressive (this does not have relapses but is constantly progressive)
Sensory (does not run into disability)
Malignant
