Multiple sclerosis patho-physiology

Question 1

What is multiple sclerosis

Answer 1

Multiple Sclerosis (MS) is a chronic autoimmune disease of the central nervous system (brain and spinal cord), where the immune system mistakenly attacks the myelin sheath — the protective covering around nerve fibers. This leads to inflammation, demyelination, and disrupted communication between the brain and body, causing a wide range of neurological symptoms such as fatigue, muscle weakness, numbness, coordination problems, and vision disturbances.

Question 2

Left Motor Cortex (Frontal Lobe) / Corticospinal Tract

Answer 2

*Main pathology in MS — demyelination disrupts motor signal transmission to the opposite side of the body.
*Relevant symptoms in Mrs. Ahmed:
- Weakness in right upper limb and right lower limb
- Difficulty lifting her baby (right arm weakness)
- Poor control when standing up
- Swaying when walking and standing

Question 3

Cerebellum / Cerebellar Pathways (e.g., cerebellar peduncles)

Answer 3

*Main pathology in MS — lesions here affect coordination and balance.
*Relevant symptoms in Mrs. Ahmed:
- Right leg incoordination (struggles pushing pram)
- Postural instability, needs to adjust posture frequently
- Trunk sway when walking
- Avoids unsupported sitting due to poor trunk control

Question 4

Sensory Pathways – Spinothalamic Tract and Dorsal Columns (Spinal cord or brainstem)

Answer 4

*Main pathology in MS — demyelination impairs sensory signal transmission.
*Relevant symptoms in Mrs. Ahmed:
- Burning sensations and patches of numbness (torso, right thigh)
- Altered sensation affecting comfort and function

Question 5

Brainstem / Autonomic Centers

Answer 5

*Main pathology in MS — brainstem lesions disrupt autonomic regulation.
*Relevant symptoms in Mrs. Ahmed:
- Dizziness on standing (resolves after ~10 seconds)
- Initial instability when transferring to standing position

Question 6

Widespread CNS Fatigue Mechanisms

Answer 6

*Main pathology in MS — inefficient nerve conduction increases energy demand.
*Relevant symptoms in Mrs. Ahmed:
- Severe fatigue, requiring naps throughout the day
- Short walking distances only
- Reduced participation in hobbies (swimming, painting)