The pictures may be difficult to look at, but 18-month-old Roona Begum's story of survival is remarkable. Soon after she was born in a remote village in northeastern India, Roona was diagnosed with an extreme form of hydrocephalus -- a disorder causing cerebral fluid to build up in the brain. Doctors had given Roona just a few months to live. Roona's head grew to a circumference of 94 centimeters, almost triple the size of a normal baby. There were ten liters of excess fluid inside her brain. Her head was so heavy she could barely move. Hydrocephalus is more common among infants and older adults. The condition is caused by overproduction, obstruction or lack of absorption of the cerebral fluid in the brain. The skin of her head has stretched so far, it pulled her eyelids over her eyes, making it impossible for Roona to see.