Multiple Sclerosis Diagnosis

Multiple Sclerosis (MS)

• MS is an autoimmune disease of the central nervous system (CNS) characterized by chronic inflammation, demyelination, gliosis, and neuronal loss.

Clinical Features

• Vision symptoms: vision loss, double vision, optic neuritis
• Vestibular symptoms: vertigo, gait imbalance
• Bulbar dysfunction: dysarthria, dysphagia
• Motor: weakness, tremor, spasticity, fatigue
• Sensory: loss of sensation, paresthesia, dysesthesias
• Urinary and bowel symptoms: incontinence, retention, urgency, constipation, diarrhea, reflux
• Cognitive symptoms: memory impairment, impairment of executive functions, trouble concentrating
• Psychiatric symptoms: depression, anxiety

Investigations

• MRI brain and spinal cord with contrast
• CSF analysis
• Evoked potentials (optional)
• Blood studies: CBC, TSH, vitamin B12, sedimentation rate, and ANA

MRI Findings

• Lesions are T2 hyperintense (white), T1 isointense/hypointense
• Lesions are classically oval
• High predilection for periventricular white matter
• Lesions are perpendicular to the ependymal surface (Dawson's fingers)
• Contrast enhancement with active lesions: diffuse or rim enhancement
• Cord lesions typically involve the cervical or thoracic cord

CSF Findings

• Elevated protein
• Leukocytes less than 50 (occasionally seen, typically mononuclear cells)
• Increased total IgG index, oligoclonal bands

Differential Diagnosis

• Other demyelinating or inflammatory CNS syndromes: optic neuritis, acute disseminated encephalomyelitis, neuromyelitis optica, partial transverse myelitis
• General inflammatory and autoimmune syndromes: systemic lupus erythematosus
• Infectious etiologies: Lyme disease, HIV, herpes viruses
• Vascular etiologies: migraine headaches, vascular malformations, emboli
• Metabolic causes: vitamin deficiencies, thyroid disease
• Neoplastic causes: primary CNS malignancies, metastasis

Prognosis

• Varies between patients
• Almost 10% of cases present before the age of 18

Pathogenesis

• Focal inflammation resulting in plaques and injury to the blood-brain barrier (BBB)
• Neurodegeneration with microscopic injury involving different components of the CNS: axons, neurons, synapses

Disease Course

• Relapsing-remitting (RR): 70-80% of MS patients, characterized by exacerbations and relapses
• Primary progressive (PP): 15-20% of patients, gradual deterioration from the onset
• Secondary progressive (SP): gradual neurologic deterioration after an initial RR course
• Clinically isolated syndrome (CIS): a single episode of inflammatory CNS demyelination

Etiology

• Unknown, but factors involved in pathogenesis include:
  • Immune factors: autoimmune attack on the CNS
  • Environmental factors: latitudinal gradients, vitamin D deficiency, infections (e.g. Epstein Barr virus)
  • Genetic associations