Multiple Sclerosis and Other Myelopathies Flashcards
Natalizumab
Anti-α4 integrin subunit. Prevents T cell recruitment to regional lymph nodes.
Progressive multifocal leukoencephalopathy is a common consequence of use. PML is an opportunistic CNS viral infection caused by the John Cunningham Virus. The risk of developing PML with natalizumab treatment is related to three factors:
- Whether the patient has antibodies to the JC virus
- Whether the patient has received prior immunosuppressive therapy
- Length of treatment with natalizumab beyond 2 years
anti-JC antibody screening required. In patients who are not found to have JC virus antibodies, the risk of developing PML is exceedingly low. Given these risks, JC virus antibody–negative patients on natalizumab therapy must be screened for JC virus antibody every 6 months to evaluate for seroconversion
Fingolimod
S1P receptor agonist. Oral therapy for MS.
Downregulates S1P receptor within the lymphatic system, preventing T cells from following the chemotactic gradient and egressing. In effect, fingolimod decreases the cycle frequency of T cells and increases the lymphatic T cell storage at any given moment.
Bradycardia and macular edema are sometimes seen. Baseline electrocardiogram (ECG) and cardiac monitoring are required with the first dose. Baseline ophthalmologic examination and subsequent periodic ophthalmologic monitoring are also necessary.
John Cunningham virus
One of the two major polyomaviruses.
Causes progressive multifocal leukoencephalopathy. In this disease, patients develop CNS white matter damage. May cause memory loss, poor speech, and impaired coordination.
Uthoff’s phenomenon
Recurrence or emergence of neurologic symptoms with heat (due to environmental temperature in the summer, hot bath, or exercise).
This occurs with any demyelinating disease/myelitis. This is why MS tends to flare in the early summer.
L’hermitte’s sign
Electrical sensation down the spine with forward flexion of the neck.
This can occur in any type of cervical myelopathy and is not specific to MS
Internuclear ophthalmoplegia
Due to disruption of the medial longitudinal fasciculus (MLF)
Afferent pupillary defect
Due to prior optic neuritis.
An afferent pupillary defect may be present even in patients who have not had a clear clinical episode of optic neuritis
When you swing the light, if both pathways are intact, pupillary size should not change. If one pathway is relatively defective, both pupils will dilate when the ipsilatreal eye is illuminated.
Neuroimaging of MS
- Key diagnostic test for MS is MRI
- Classic radiologic features of MS are small, ovoid T2/FLAIR hyperintensities that are perpendicularly oriented to the lateral ventricles and corpus callosum.
- Acute lesions may demonstrate enhancement with gadolinium, often in an open ring (as compared to the complete ring of contrast enhancement seen with tumor and abscess)
- The damage caused by lesions over time can lead to T1 hypointensities at sites of prior demyelination (T1 black holes).
Visual Evoked Potentials
- Examine a particular EEG of visual stimulation (P100) to evaluate conduction along the visual pathway.
- If the latency of P100 between the two eyes is significantly different, this suggests slowed conduction in one optic nerve, a sign of optic nerve dysfunction
- In cases of possible MS, abnormal VEPs can suggest prior optic neuritis.
- The optic nerve can also be examined by optical CT to look for prior damage to the nerve.
Pupillary reflex pathway
In order to diagnose MS, you need . . .
. . . multiple lesions that are separated by BOTH time AND space
In other words, many different lesions all at once is NOT MS, and repeated episodes of unifocal myelitis at one spot is NOT MS.
Optic neuritis
- Painful loss of visual acuity in one eye
- Common presenting symptom of MS, but may be due to a number of different myelopathies
- Features:
- Loss of visual acuity
- Red desaturation
- RAPD
- Optic disc pallor or atrophy on exam
- Pulling or tugging pain with EOMI
Transverse myelitis
- Inflammatory demyelination of the spinal cord
- Reflexes may be exaggerated below the level of the lesion
- Babinski signs may be present
- Patients may report a “band of tingling or pain” around the torso at the level of the lesion
Internuclear ophthalmoplegia
Five major features that suggest MS
- Optic neuritis
- Transverse myelitis
- Internuclear ophthalmoplegia
- Lhermitte’s sign
- Uhthoff’s phenomenon
Four different phenotypes of multiple sclerosis natural history
- Relapsing-remitting (no baseline symptoms between episodes)
- Progressive relapsing MS (starts as progressive symptoms, then with superimposed relapsing MS. Never remitting)
- Secondary progressive phase (starts as relapsing remitting, then progresses with or without further superimposed relapses)
- Primary progressive multiple sclerosis (no episodic exacerbations, just baseline change)
LP for MS diangosis
Oligoclonal bands are the classic finding
Reflect the intrahectal production of IgG by plasma cell clones within the CNS
Nonspecific and can be seen in CNS infections and other CNS inflammatory conditions
Fingolimod
Mixed agonist-antagonist of the S1P Receptor
Downregulates S1P receptor within the lymphatic system, preventing T cells from following the chemotactic gradient and egressing. In effect, fingolimod decreases the cycle frequency of T cells and increases the lymphatic T cell storage at any given moment.
Bradycardia and macular edema are sometimes seen. Baseline electrocardiogram (ECG) and cardiac monitoring are required with the first dose. Baseline ophthalmologic examination and subsequent periodic ophthalmologic monitoring are also necessary.