1- Epidemiology:
– The risk of developing MS depends on the region where prevalence of the first 15 years of his life were spent.
– There is a north-south gradient higher prevalence north.
– Predominance 60% female; the mean age of onset is 30 years. 70% between 20 and 40 years
2- Pathophysiology:
– In early inflammation (mononuclear lymphoplasmacytic infiltrate, perivascular) and disintegration of the myelin (phagocytosed by macrophages).
– Demyelination respects relatively axons: the axons myélino-dissociation.
– The remyelination is more or less complete, accompanied by a reaction astrocytic gliosis.
– Suffering axonal (from the beginning of the disease) resulting in permanent disability. Coexistence of different ages plates (dissemination in time) of a diffusely in the CNS (dissemination in space).
– The gray matter and the peripheral nervous system are generally respected
– Cranial nerves can be achieved in their intranévraxique path (eg: V and VII)
– A secondary axonal damage is possible after several outbreaks explaining the effects between relapses.
– Paroxysmal phenomena are associated with membrane phenomena (conduction block) and not with demyelination.These conduction blocks are aggravated by heat and acidosis.
– On the etiological, many factors are incriminated: viruses (measles Ac ++); environment (childhood); Autoimmunity: intrathecal synthesis of Ig polyclonal; reduction of CD8 + T cells at the time of relapses (which are high in remission).Role of TNFa and IFN.gamma. Production of Ac antimyéline. There is a genetic predisposition, but familial forms are rare.
3- Clinic:
– Evolution marked by regressive attacks (relapsing remitting, the most common).
– Common sensory disorders and sometimes features. paresthesia; Contact dysesthesia; Lhermitte’s sign, which is an equivalent of a later cordonale reached with brief electric shock sensation triggered by the flexion of the neck, down along the back and limbs in-férieurs.
– Motor impairment (pyramidal and cerebellar)
* The achievement of the pyramidal tract is common (80% after 5 years of evolution); different clinical forms (monoplegia hemiplegia …) py-ramidal syndrome (see the course)
* Cerebellar syndrome (50% of cases) with static and kinetic tremor often often disabling intensional
– Optic nerve: almost constant, often with subclinical altered only ENP. It carries a retrobulbar optic neuropathy. 22% of ESP begins with the infringement. It results in a sudden drop in visual acuity, sided with orbital pain. Sometimes incomplete with impaired vision colors (red-green color blindness) and central scotoma. The fundus is normal at first appears secondarily pallor of the temporal segment of the disc.
– Infringement of the brainstem:
* Disorders of oculomotor: diplopia is common, often linked to a internuclear ophthalmoplegia or ISO (III <=> VI).
In case of ISO, the eye in abduction (VI) is not followed by contralateral eye (III), where a horizontal diplopia, while the convergence of the eyes is possible. Bilateral ISO is highly suggestive of September
* Symptomatic Trigeminal V (trigeminal): lightning pains in the V territories, there hypoesthesia and abolition of the corneal reflex on the same side (eliminating an essential neuralgia V).
* Facial paralysis of peripheral type
* Vestibular Syndrome central type (disharmonious, fleeting dizziness, nystagmus multidirectional).
* NB: deafness is rare but subclinical alteration of the PEA is common.
– Sphincter and sexual disorders: frequent, almost constant after a change of more than 10 years. urinary urgency and urinary frequency, dysuria, residual urine. Impotence and frigidity.
– Psychiatric disorders: mood (depression), intellectual impairment on attention, memory, rarely subcortical dementia.
– Other signs:
* General signs: very common asthenia,
* Paroxysmal Events: brief tonic seizures; paroxysmal dysarthria; neuralgia (sensitive Tegretol carbamazepine).
* Important Signs: clinical worsening or appearance of new events related to sustained physical effort, strong heat, a warm bath or during a febrile syndrome (conduction block).
* Negative signs: no cortical involvement (no aphasia or apraxia, epilepsy exceptional); by the reach of the SNP; no extrapyramidal signs; outstanding homonymous hemianopia.
* Possible pupillary abnormalities: Argyll-Robertson (anisocoria with abolition of photomotor and conservation accomodation-convergence reflex); pupillary Marcus-Gunn phenomenon (mydriasis paradoxical to the illumination of the eye affected by retrobulbar optic neuritis
4- Additional tests:
– In consideration’re specific to multiple sclerosis.
– FNS normal, no inflammation, normal ESR.
– LCR: Hypergammaglobulinorachie evocative (> 12% of the total protein) due to an intrathecal IgG synthesis with no known antigen specificity. It is oligoclonal distribution (oligoclonal band), absent from the serum. Lymphocytic pleocytosis (<50 cells / mm3) can be observed; normal LCR does not eliminate the Dc; lack of correlation between CSF abnormalities and severity of outbreaks.
– MRI: clinicopathological dissociation; in suspension and soustentoriel and marrow; in the white matter and especially periventricular. T1: hypointense taking gadolinium plate when young (<3 months). T2: hyperintense areas. No mass effects. They are not specific in September They vary from one exam to another. Atrophy of the corpus callosum is frequently observed. Taking Gadolinium is a marker of disease activity. CT is less sensitive than MRI (recent isodense plates and take the contrast; the old plates are hypodense and are not enhanced by the product). At a more advanced stage -> ventricular dilatation.
– Multimodal evoked potentials (AEP, EPI, PES PEM) show the same lesions subclinical; multifocal lesions
5- positive diagnosis:
– Dissemination in time; dissemination in space, intrathecal synthesis of Ig (CSF); absence of other causes (MS remains a disposal Dc)
– Two clinical exacerbations with two distinct anatomical lesions sufficient to confirm the diagnosis of MS.
6- Development:
– Onset may be monosymptomatic in 50% of cases
– The development by regressive outbreaks is frequent (80%); is relapsing remitting. Which is characteristic of MS
– The thrust is defined by the appearance of new signs or worsening of pre-existing sign, outside of any intercurrent factor, for more than 24 hours and occurring over a month for the final push.
– Remission is defined by a persistent improvement in signs for at least one month.
– Regression of signs is under at least complete, leaving scars between relapses
– Secondary progressive forms: after 10 years of development, half of the patients present with progressive defined as a progressive worsening of neurological disorders for at least 6 months.
– The primitively progressive (15%) is essentially marrow; after 40 years; without female
– Gait: after 6 years of evolution
– Patient confined to his home: after 18 years of evolution
– Median survival: 35. decubitus complication deaths; urinary infection
– Poor prognosis factors: late onset, progressive forms, short interval between the first two outbreaks, intellectual deterioration.
7- Treatment:
– Corticosteroids: Symptomatic treatment at the time of thrust; reduce the length of the thrust; do not prevent subsequent relapses; does not influence the course of the disease.
– Antispasmodic: baclofen, dantrolene
– Immunosuppressive drugs (DMARDs) are reserved for severe cases. Azathioprine (severe flare to form);cyclophosphamide (secondary progressive).
– Immunomodulators (DMARD); interferon beta (IFN beta) which acts by opposing the toxic effects of the IFN.gamma and TNF and activating the suppressor cells.