The problem is that Lupus is an unpredictable disease and it changes within us. New symptoms appear and old symptoms may disappear and/or worsen. Lupus flares are also unpredictable and can occur suddenly and each new flare can be completely different from the last flare you had.
When your Lupus is in a flare, it can attack several organs in your body at the same time.
Some of us can have Lupus for years without having any serious flares and then, suddenly, our flares are serious and affecting many parts of our body. There is really no way of knowing why this occurs and, therefore, no way to answer your question except to say that this is the henious nature of the disease. :?
Peace and Blessings
Look For The Good and Praise It!