Bilateral facial paralysis can be caused by a number of conditions. The most common of these are the congenital condition, Mobius syndrome, or Lyme disease. Another frequent cause of bilateral facial paralysis is Guillain-Barré syndrome, which is an ascending polyneuropathy, with an auto-immune component. There is a variant of GBS that only involves the face, which is called Miller Fisher syndrome, and is treated the same way as GBS. Often GBS and Miller Fisher syndrome are triggered by some kind of viral infection.
Other causes of bilateral facial paralysis include bilateral skull fractures involving both temporal bones, certain kinds of brain infections like meningitis, certain cancers like lymphoma that get into the spinal fluid, causing bilateral weakness. Sarcoidosis, a granulomatous disease, can also cause bilateral facial paralysis, as can certain kinds of leukemia, infectious mononucleosis (mono), and acute HIV infection.
Treatment for bilateral facial paralysis is completely dependent upon what has caused it. Certain conditions, like temporal bone fractures, might require surgery, where others require medical therapy specifically to control the disease which is causing the nerve problem. Extremely personalized diagnosis and management is essential when patients develop bilateral facial weakness.