What Causes Recurring Severe Headache Resulting In Loss Of Consciousness?

hii...dr my sister name is khusboo...she is a suffering from disease ...but not even any specialist doctors can t identified his disease ...she has a problem of headaches ...but it s a kind of attack wich comes with lot of pain and after a min she become uncious again again this process is continued till she is admitted to any hospital ..she get relif by simple pain killer injections... and after some hours headache starts again ...i have show her to all the specialists neuroligist dr from PGI lucknow ...to AIMS delhi. but she could not get relif