Multiple sclerosis (MS) is a disease that affects the central nervous system—the brain and spinal cord. It also affects the nerves to the eyes. It can cause problems with muscle strength, vision, balance, mood, sensation, and thinking.

Your nerve cells have a protective covering called myelin. Without myelin, the brain and spinal cord can't communicate with the nerves in the rest of the body. MS causes areas in the brain and spinal cord to get inflamed. It slowly damages the myelin and nerves in patches. These patches of damage are called lesions.

MS tends to get worse over time. But usually this happens slowly. It's hard to predict how MS will affect you. MS is different for each person. Some people's lives won't change much with MS. Those people may function well for a long time. But others may lose the ability to walk or do everyday tasks as the disease gets worse.

There is no cure for MS. But medicines and other treatments might help slow its progression and treat your symptoms.

The symptoms of MS vary from person to person. Which symptoms you have will depend on which parts of your brain or spinal cord are damaged. Over time, symptoms may come and go, or they may be long-lasting. Certain things like being hot or having an infection may cause symptoms to get worse for a short time. As MS progresses, symptoms may get worse.

Common symptoms

• Feeling very tired (fatigue).
• Muscle symptoms. These include weakness, stiffness, and spasms. You may be clumsy or have a tremor. These problems may make it hard to hold on to things or walk. Over time, a cane or wheelchair may be needed.
• Visual symptoms. These include blurry vision, eye pain, blindness, and double vision. Optic neuritis—a sudden loss of vision that's often painful—may be a first symptom of MS.
• Sensory symptoms. These include numbness and tingling, feelings of pins-and-needles, and coldness. They may occur in a limb or on your face or body. You may also feel a band of tightness around the trunk of your body.
• Pain. This may include headaches, nerve pain, and pain from muscle spasms.
• Bladder symptoms. These may include a need to urinate often. Or you may not be able to control or empty your bladder. You may wake up at night to urinate.
• Constipation and other bowel symptoms. You may have a hard time passing stool (constipation). Or you may lose control of your bowels.
• Sexual problems. You may be less interested in having sex. Or you may have pain during sex or have problems getting an erection.
• Cognitive problems. You may have trouble focusing. You may forget things. Or you may have trouble thinking quickly or solving problems.
• Mental health symptoms. You may feel depressed or anxious.
• Sleep problems.
• Vertigo and balance problems. You may feel dizzy or unsteady.