Multiple sclerosis Flashcards
A 39 year old femal presents with a burning sensation affecting her arms and legs over the last few weeks. Additionally, she has noted her vision has become blurry, and finds it difficult to discern the colour red.
On examination she has 3/6 vision in her left eye. The right eye is normal.
What is the diagnosis?
Optic neuritis
From this presentation alone, the diagnosis of Multiple Sclerosis cannot be made as the lesion must be disseminated in time and space. This lesion is disseminated in space but not in time.
Causes of optic neuritis
- Demyelination eg MS
- Infection eg Lyme’s disease
- SLE
- Sarcoidosis
- Vasculitides
- Idiopathic
What is optic neuritis?
Inflamation of the optic nerve
Symptoms of optic neuritis
- Blurred vision
- Loss of red colour vision
Define multiple sclerosis
Chronic autoimmune disorder of the CNS resulting in demyelination of white matter.
What cell is affected in MS? Why is this significant?
Oligodendrocytes
They only exist in the central nervous system
Risk factors for multiple sclerosis
- Age: 20-40 years old
- Female: 3 x more common
- Family history: HLA-DR2
- Autoimmunity
- Vitamin D deficiency
- EBV infection
Which is the most common type of MS?
Relapsing remitting
About 85% of patients have this form at disease onset
What are the types of multiple sclerosis?
-
Relapsing remitting
- Episodic flare-ups (may last days, weeks or months), separated by periods of remission
- After each successive relapse, disability increases
- 60% of patients develop secondary progressive MS within 15 years
-
Secondary progressive
- Initially, the disease starts with a relapsing-remitting course, but then symptoms get progressively worse with no periods of remission
- Associated with co-ordination difficulties and bladder/bowel issues
-
Primary progressive
- Symptoms get progressively worse from disease onset with no periods of remission
- Accounts for 10% of cases and is more common in older patients
- Progressive relapsing
Symptoms of multiple sclerosis
- Blurred vision and red desaturation
- Numbness, tingling and other strange sensations
- Weakness
- Bowel and bladder dysfunction
- Uhtoff’s phenomenon: worsening of symptoms following a rise in temperature, such as a hot bath
Signs of multiple sclerosis
- Visual
-
Optic neuritis
- Pale optic disc and inability to see red
- Relative afferent pupillary defect
- Unilateral or bilateral internuclear opthalmoplegia
-
Optic neuritis
- Sensory loss: due to demyelination of spinothalamic or dorsal columns
- Upper motor neuron signs with spastic paraparesis are common
- Cerebellar signs such as ataxia and tremor (usually in a relapse)
- Lhermitte’s phenomenon: electric shock sensation on neck flexion
What is demyelinated in internuclear opthalmoplegia?
Medial longitudinal fasiculus (MLF)
How does internuclear opthalmoplegia present?
- Can be unilateral or bilateral
- For example, with right sided INO, i.e. a right MLF lesion, the patient cannot adduct their right eye when looking left
What diagnostic criteria is used to diagnose MS?
McDonald criteria
Diagnosis is based on:
- 2 or more relapses AND EITHER
- Objective clinical evidence of 2 or more lesions OR
- Objective clinical evidence of one lesion WITH a reasonable history of a previous relapse
- ‘Objective evidence’ is defined as an abnormality on neurological exam, MRI or visual evoked potentials
Investigations for MS
-
MRI brain and spine:
- Demyelinating plaques appear as high signal on T2 MRI
- New lesions: enhance with gadolinium contrast
- Old lesions: do not enhance
- Lumbar puncture: oligoclonal IgG bands in the CSF and not in the serum
- Visual evoked potentials: delayed velocity but a normal amplitude
