Multiple sclerosis

TheraspOT

6 min readAug 24, 2020

Multiple sclerosis (MS), the most prevalent neurological disability, is an autoimmune-mediated disorder that affects the central nervous system (CNS) and often leads to severe physical or cognitive incapacitation as well as neurological problems in young adults.
The course of MS is highly varied and unpredictable. In most patients, the disease is characterized initially by episodes of reversible neurological deficits, which is often followed by progressive neurological deterioration over time.

ETIOLOGY

The etiology of MS, an autoimmune disease of the central nervous system, is still unknown, but some risk factors have been implicated in its pathogenesis, including an association of genetic susceptibility and environmental agents. Season of birth, EBV infection, vitamin D deficiency, and smoking are strongly involved in the development of multiple sclerosis
The births of patients with multiple sclerosis follow a seasonal distribution, being more frequent during the spring and winter and less frequent during the autumn; it is hypothesized that this could reflect low maternal vitamin D during pregnancy.
Moreover, concentrations of vitamin D are lower in patients with multiple sclerosis than in controls and, among patients with multiple sclerosis, lower concentrations of vitamin D are associated with progressive forms of the disease, increased disability, and clinical activity and risk of relapse.

PATHOLOGY

Gliosis- proliferation of the neuroglial cells. Oligodendrocytes form the myelin sheath in CNS

Multiple sclerosis affects white matter but in later stages, gray matter is also affected.

The blood–brain barrier (BBB) is a protective barrier that denies the entrance of foreign material into the nervous system. BBB disruption is the moment in which penetration of the barrier by lymphocytes occur and has been considered one of the early problems in MS lesions.

The BBB is composed of ENDOTHELIAL CELLS which line the blood vessel walls of the central nervous system. Compared to normal endothelial cells, the cells lining the BBB are connected by occludin and claudin which form tight junctions in order to create a barrier to keep out larger molecules such as proteins. In order to pass through, molecules must be taken in by transport proteins or an alteration in the BBB permeability must occur, such as interactions with associated adaptor proteins. After barrier breakdown symptoms may appear, such as swelling. Activation of macrophages and lymphocytes and their migration across the barrier may result in direct attacks on myelin sheaths within the central nervous system, leading to the characteristic demyelination event observed in MS

TYPES OF MULTIPLE SCLEROSIS

There are 4 types of multiple sclerosis, named according to the way the disease acts on the body over time:

Relapsing-Remitting MS (RRMS). This is the most common form of multiple sclerosis. About 75% to 85% of people with MS are initially diagnosed with RRMS. People with RRMS have temporary periods called relapses, flare-ups or exacerbations, when new symptoms appear. Relapses typically last a few days or weeks. At other times, the symptoms seem to disappear and this is called a remission; however, MS is still active and can progress. Damage to nerves can still occur even though there are no symptoms.
Secondary-Progressive MS (SPMS). In SPMS symptoms worsen more steadily over time, with or without the occurrence of relapses and remissions. Before disease-modifying therapies became available, historical studies indicated that about 50% of people with RRMS progressed to SPMS approximately 10 years after their first diagnosis. Long-term data are not yet available to determine if treatment significantly delays this transition
Primary-Progressive MS (PPMS). This type of MS is not very common, occurring in about 10% of people with MS. PPMS is characterized by slowly worsening symptoms from the beginning, with no relapses or remissions.
Benign multiple sclerosis (MS) is a mild course of MS seen in 5–10% of MS patients. In people affected by benign MS, there is no worsening of functional ability even after 15 years of diagnosis. Currently, there is no way of predicting this form of MS at the time of diagnosis. Benign course of MS is characterized by the absence of relapses and stable disability after 20–30 years of diagnosis.

CLINICAL FEATURES

Classic MS symptoms are as follows:

Sensory loss (ie, paresthesias) — Usually an early complaint
Spinal cord symptoms (motor) — Muscle cramping secondary to spasticity
Spinal cord symptoms (autonomic) — Bladder, bowel, and sexual dysfunction.
Cerebellar symptoms — Charcot triad of dysarthria (scanning speech), nystagmus, and intention tremor
Optic neuritis
Trigeminal neuralgia — Bilateral facial weakness or trigeminal neuralgia
Facial myokymia (irregular twitching of the facial muscles) — May also be a presenting symptom
Eye symptoms — Including diplopia on lateral gaze; these occur in 33% of patients
Heat intolerance- Overheating, or heat intolerance, may result in blurring of vision (Uhthoff sign), usually in an eye previously affected by ON. These symptoms result from elevation of core body temperature, which further impairs conduction by demyelinated nerves, and they typically reverse rapidly when exposure to high temperature ends.
Constitutional symptoms — especially fatigue (which occurs in 70% of cases) and dizziness; fatigue must be differentiated from depression (which may, however, coexist), lack of sleep, and exertional exhaustion due to disability
Pain — Occurs in 30–50% of patients at some point in their illness. Lhermitte’s sign is a short, intense sensation that feels similar to an electric shock passing down the neck and spine and radiating through the trunk and limbs. While not specific to multiple sclerosis, people with the disease most often report it.
Subjective cognitive difficulties — With regard to attention span, concentration, memory, and judgment
Depression — A common symptom
Euphoria — Less common than depression
Bipolar disorder or frank dementia — May appear late in the disease course but is sometimes found at the time of initial diagnosis.
Partial, rather than total, acute transverse myelitis usually is a manifestation of MS. Acute partial loss of motor, sensory, autonomic, reflex, and sphincter function below the level of the lesion indicates acute transverse myelitis.
Fatigue is one of the most common symptom of MS, reported by at least 75% of patients with the disease. Fatigue is described as an overwhelming feeling of lassitude or lack of physical or mental energy that interferes with activities.
Spasticity in MS is characterized by increased muscle tone and resistance to movement; it occurs most frequently in muscles that function to maintain upright posture. The muscle stiffness greatly increases the energy expended to perform activities of daily living (ADLs), which in turn contributes to fatigue.
Urinary symptoms are common in MS, with most patients experiencing problems at some point in their disease. Bladder problems are a source of significant morbidity, affecting the person’s family, social, and work responsibilities. Bladder dysfunction can be classified as failure to store, failure to empty, or both. Patients with impaired storage have a small, spastic bladder with hypercontractility of the detrusor muscle. Symptoms experienced may include urgency, frequency, incontinence, and nocturia. MS patients with advancing disability and impaired bladder function may experience recurrent urinary tract infections.
Gait- usually spastic- ataxic type.