Smoldering multiple sclerosis (MS) is a chronic process that occurs in the brain and spinal cord of people with MS, even during remission: Explanation Smoldering MS is a slow, ongoing process of damage that occurs when areas of the brain remain active, causing destruction. This process is similar to smoldering embers, and is thought to be a major driver of disability progression. Cause Smoldering MS is characterized by the persistent activation of microglia, the brain's immune cells, at the edges of lesions. Microglia are normally responsible for clearing up broken-up myelin in areas of damage, but in MS they seem to remain persistently activated. Symptoms Smoldering MS can cause a range of symptoms, including cognitive worsening, fatigue, pain, blood disturbances, and psychiatric disturbances like depression. Treatment Most current therapies don't address the chronic inflammatory processes that cause smoldering MS, which is why disability continues to progress. However, researchers are working to identify new ways to detect and treat smoldering MS. Lifestyle factors Some lifestyle factors can make smoldering MS worse, including not exercising, eating poorly, smoking, drinking too much alcohol, not sleeping well, taking certain medications, and having other health problems.