Multiple sclerosis (MS) happens when your immune system attacks myelin, the sheath around your nerve cells. Without this outer shell, your nerves become damaged and cause communication problems between your brain and the rest of your body. Thank you @kayla_unstable for this helpful explainer! #multiplesclerosis #chronicillness #invisibleillness #spoonie #autoimmune #msawareness #ms #msfighter #mslife #webmd