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IOWA CITY, Iowa (CBS Local) – An Iowa teen dealing with headaches is now fighting for his life after doctors discovered he was actually suffering from a rare brain disease.

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Christopher Bunch told his parents he had a headache on Aug. 6, but decided to go to football practice anyway. When the pain did not go away, the 14-year-old’s coaches reportedly sat him down for the remainder of practice before going home.

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According to the boy’s parents, that’s when Christopher went to sleep for nearly a day before trying to return to football practice on Aug. 7. “He then had practice at 3pm again and started vomiting. He went home and fell asleep around 7pm and slept until around 8pm Wednesday night,” the boy’s family wrote on Facebook.

Christopher was rushed to the hospital where doctors diagnosed him with acute disseminated encephalomyelitis (ADEM). The rare illness is an inflammation of the brain and spinal cord. The autoimmune disease reportedly comes on rapidly, however, an exact cause for why it develops is still not known.

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Iowa doctors told local reporters that the teen’s illness is the worst case of ADEM they’ve seen. He stopped breathing on his own just hours after arriving at the hospital.

“From that point on, everything just spiraled downhill,” the boy’s father, Elijah Bunch said, via WREG. “His progression went from zero to 100 in a matter of four hours.”

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The family has set up a donation page on social media to help cover the 14-year-old’s ongoing medical expenses. Doctors say his prognosis does not look promising.

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“I’m so happy we had 14 beautiful years with him, but I’m so mad that’s all that we got,” the teen’s father added.