I was wondering how many lesions a year were considered normal for relapseing remitting multiple sclerosis in a young adult? 25yrs old.

Multiple sclerosis: You are referring to relapse rate without treatment which varies widely. We lack markers that would identify those with a higher risk of more aggressive disease. The rate could be 1.27-1.44 relapses per year without treatment (4 in 3 years or 3 in 2 years). Most therapies available reduce the relapse rate. Physicians use reported relapses and exam along with MRI to check for response to therapy.

Predicting Outcome: Factors that predict unfavorable prognosis are: 1. Primary or secondary progressive course 2. Older age at onset (> 25) 3. Male sex 4. First interval between attacks shorter than one year 5. Initial cerebellar or pyramidal (motor) symptoms 6. Moderate to severe disability within the first 2 years. Link to more info: http://www.Ncbi.Nlm.Nih.Gov/pmc/articles/pmc1073365/pdf/jnnpsyc00027-0030.Pdf.

Some understanding: If your medication is working well, you should have less than one new T-2 or expanding old T-2 lesion, and no contrast positive T-1 lesions. Glad you are taking Tysabri, (natalizumab) which should readily control your disease. Please note that summer heat can result in appearance of more T-2 lesions and this should not concern you or your doctor unless relapses are occurring. Please supplement Vitamin D-3.