Flare-ups in multiple sclerosis (MS) are distinct, sudden episodes of either new symptoms or a worsening of existing symptoms. They are characteristic to the relapsing-remitting MS (RRMS), which is marked by recurrent acute flares (or relapses) followed by partial or complete recovery (or remission).

Approximately 85 percent of all MS patients are initially diagnosed with RRMS. The remaining 15 percent have what is called primary-progressive MS (PPMS), and undergo a gradual physical decline with no noticeable remissions.

Characteristics of flare-ups in multiple sclerosis

A flare may consist of one or more symptoms that last for 24 hours or more — including weeks or months. To be a flare, symptoms must be specific to MS and not due to other factors such as infection. Two distinct flares are separated by a remission period of at least 30 days. (Flares are also known as attacks, relapses, episodes or exacerbations.)

The underlying mechanism for a flare is the immune attack on myelin sheath (outer insulating layer on nerve fibers), which causes slow or interrupted neuronal signals in the brain and spinal cord. This results in flare such symptoms as problems with balance, coordination, eyesight, bladder, memory or concentration, mobility, fatigue, and weakness, numbness or needle-like sensations. Remission occurs when inflammation reduces and myelin sheath gets replaced so that the transmission of neuronal signals is recovered.

Flares could be triggered by various factors such as stress, infections or pregnancy.

The symptoms vary from mild to severe.

Managing relapses

Mild symptoms such as fatigue, numbness and needle-like sensations could be left to subside and need no treatment.

For severe flares (such as vision loss, extreme weakness, and poor balance) that interfere with patients’ everyday activities, experts recommend a short-course with high-dose of corticosteroids. Steroids facilitate recovery from a relapse by reducing inflammation but do not affect the course of MS. The most common treatment regime is a three-to-five day course of intravenous Solu-Medrol (methylprednisolone). Oral Deltasone (prednisone) may also be used.

Steroid treatment works best if started immediately after the flare onset. However, steroids have side effects that can include increased appetite, weight gain, higher blood pressure, and thinning of bones.

Plasmapheresis, a blood-cleansing method to remove the myelin-attacking antibodies from the plasma, is an option for treating severe relapses that do not respond to the standard steroid treatment.

Patient rehabilitation aims to restore the essential everyday functions after a relapse. It combines different approaches including physiotherapy, dietary advice, employment services, and support at home. The rehab team helps the patient with difficulties in swallowing, mobility, dressing, personal care, and office work.

Recovery from a relapse may take weeks or months, with symptoms disappearing completely or partially.