madison small , from ashburn , left school early on mondayand , after she woke up in the night with a severe headache , she was rushed to hospital .
by tuesday afternoon , her father , tim small , had contacted the broad run high school to let staff know that his youngest daughter had passed away that morning .
the loudoun county health department confirmed she died of meningococcal meningitis , which causes membranes covering the brain and spinal cord to swell .
it is caused by a bacterium that around 10 per cent of people who had contact with small would be watched for symptoms .