By Rachael Rettner, Senior Writer
Published: 02/03/2014 07:36 AM EST on LiveScience
For three years, a teen boy in North Carolina developed progressively worsening movement, speech and memory problems, but doctors remained unable to determine the cause of his deteriorating condition.
It was only after his death at age 16 that they found the answer: The boy had an extremely rare brain disorder called sporadic fatal insomnia, which is caused by prions, or abnormally folded proteins. The boy is the youngest person known to have had this disease, according to a new report of the tragic case.
Although prion diseases are rare in teenagers, the researchers wanted to publish the case to raise awareness about the condition among doctors who treat children, said Dr. Ermias Belay, of the Center for Disease Control and Prevention's National Center for Emerging and Zoonotic Infectious Diseases, who investigated the boy's case.
The boy's symptoms started back in February 2009, when he visited the emergency department for slurred speech and double vision. His doctor's initially believed his symptoms were related to two concussions the boy had experienced in the previous months, one of which occurred during football practice. But an MRI (magnetic resonance imaging) and CT scan of his head and neck appeared normal. [10 Things You Didn't Know About the Brain]
Over the following months, the boy complained of balance and memory problems, and difficulty writing. In June 2009, he was hospitalized for worsening coordination problems, including an unsteady walk, as well as a fever.
During that hospital stay, a doctor saw the boy was exhibiting involuntary movements of his arms and legs, and he was transferred to a rehabilitation center. Over the following weeks, the boy's memory and walking ability continued to decline. Doctors thought the boy might have inflammation in his brain, possibility caused by an autoimmune disease. When the boy eventually left the hospital, he was in a wheelchair and no longer able to attend school, the report said.
Over the next few years, the boy's condition continued to get worse — he had difficultly chewing and swallowing, and during one hospitalization, doctors said he appeared delirious, but it was not clear if this was due to his condition, or the medications he was taking.
In the fall of 2011, the patient was hospitalized for pneumonia, and five months later, he was re-hospitalized for life-threatening breathing problems. He was placed on a ventilator, but doctors were unable to save him, and he died in February 2012.
Doctors knew the boy had a progressive brain disease, but exactly which disease had eluded them. A postmortem analysis of his brain revealed an extremely unexpected result: The boy had a prion disease. Prions are proteins normally found in the brain that form brain lesions when they start to fold abnormally.
There are two known causes of prions forming in the brain — a person's genes, or factors in the environment. However in some cases, as with this teen boy, there is no "trigger," and these are known as sporadic cases, said Belay said.
"In the United States, prion disease in [teenagers] is extremely extremely unusual," Belay said. "This is the youngest patient, that we are aware of," to have a sporadic prion disease, he said. There is no treatment or cure for prion diseases.
One type of prion disease is Creutzfeldt-Jakob Disease, a condition that is often sporadic. But the lesions in the boy's brain were not characteristic of this condition. Instead, his brain looked similar to those of people with fatal familial insomnia, an inherited prion disease in which patients often experience worsening insomnia. Because the boy did not have the genetic mutation characteristic of people with fatal familial insomnia, he was said to have sporadic fatal insomnia.
If the boy had insomnia, it was not picked up by his doctors or his parents. Belay noted that sometimes a sleep study is needed to diagnose insomnia, but in the boy's case, this was not preformed.
Sometimes insomnia is missed because a patient's condition is so advanced that they aren't able to tell others about their sleep problems, Belay said. "They may be struggling with sleep, and they may not be able to communicate that," he said.
If a doctor is "faced with a patient with very a unusual neurological disease that cannot be explained by any other cause, then they should start considering the possibility of prion diseases, even if the patient is very young," Belay said.
The report is published online Feb. 3 in the journal Pediatrics.