check out our classic scenarios. thanks so much for watching. i'm john quinones. "20/20" starts right now. one, two, finish it! >> your child is out of control. >> yes. what am i doing wrong? and how can we help? >> tonight on an all new "20/20." >> get a handle on it. >> family home movies that reveal a nightmare. >> are you okay? >> but nobody knows why. >> it's as if you can't even recognize your own child. and yet no doctor is able to give you answers. >> something came in the window and stole our child. our kid is gone, like, gone. >> the bizarre medical mystery that some doctors say strikes children without warning. it can seem like their brains

and their bodies are on fire. >> so scary. >> their eyeballs are twitching. >> parents terrified for them and terrified by them. >> [ bleep ] you people. >> in their own homes. >> i'm going to kill you. dad, mom is going to stab himself. >> and he would sit there and chant. die sufferably. >> die sufferably. >> die sufferably. >> look what they did to me. >> in some cases, having to do the unthinkable. >> hyou had to put your 4-year-old in a psych ward. >> the hardest day of my life. >> like a prison for children. >> what's one thing they have in common? strep throat. something so ordinary it affects almost every child. >> he had strep before this all happened. >> could your child ever be at ask? >> just do something for my kid. >> good evening. i'm amy robach. >> i'm david muir, and this is "20/20." reporting tonight, juju chang with our team at "nightline."

>> get over here now! >> reporter: imagine this is your house. >> i'm going to kill you! shut up! >> reporter: imagine it's your family, in full-on crisis. >> i just kept thinking, "what's going on with my child?" >> reporter: erratic, explosive behavior developing overnight, a jekyll and hide transformation as a 4-year-old. >> it was just swings that were very dramatic and uncalled for, for the situation. >> reporter: she would be tantruming for an hour? >> there have been times where it was an hour and a half, two hours. >> reporter: alexia baier has not always been so volatile. her mom, vanessa, a special needs teacher, dad, brian, an

accountant and older sister kayla all welcomed a very typical baby girl to their loving home outside chicago. >> this is her shortly after she was born. and you can just even see she's a happy baby then. >> reporter: you guys are so cute. >> she was always laughing, smiling. >> reporter: what kind of pre-k student was she? >> she came home telling us, like "it was so great. i love my teachers. i love the school." you know, listing off every single friend in the classroom. >> she was on track. she was even advanced in different areas. she was just a simple 4-year-old. >> reporter: on track until the winter of 2014 when, as it always does, the petri dish of germs, otherwise known as pre-school, claimed its first victim. and that's when her mother says alexia's simple sore throat turned sinister. >> she wasn't really wanting to wake up from a nap. and she had minor fever. >> reporter: and what did the doctor say? >> no big deal, just run of the

mill strep throat. >> reporter: a typical course of antibiotics made short work of the strep. but curiously, at the same time the infection disappeared, so did little alexia's bubbly disposition. how long until you saw a change? >> it was less than two days later. it was defiance and ocd. she just all of a sudden seemed angry. >> reporter: it hits overnight. >> yes. >> a lot of screaming, a lot of hitting and kicking adults. >> reporter: alarmed teachers isolated alexia from the other preschoolers even resorting to using bookshelves as barricades. they snapped these chilling pictures of a classroom in chaos. >> furniture would get tipped over, bins of toys were dumped or thrown at people. when we would try and keep her safe in like an isolated area, she would just continue to elevate and elevate. >> they had to call in the

social worker, the psychologist. >> reporter: what is going on in your mind? >> a lot of guilt and blame, you know, personal blame about what am i doing wrong? and how can we help? >> reporter: mccree says the prevailing wisdom about a child suddenly acting out usually means trouble at home. but, he says, alexia was an anomaly. >> when somebody switches temperaments, we look to see is something changing at the home? whether it's the parents that are separating, you know any violence that they might be exposed to that way. and it just didn't seem to be the case with this family. >> this just isn't making sense. >> reporter: you're a special needs teacher. >> right. >> reporter: you specialize in de-escalation. >> right, exactly. >> reporter: yet, your child is out of control. >> yes. and i don't know how to deescalate my own child.

>> let me out. >> reporter: but things would become their most dire when prolonged tantrums turned into threats towards her family and herself. at one point, the 4-year-old even talked about suicide. >> telling my 6-year-old, you have to stay in your bedroom because i don't know what your sister is capable of, it was heartbreaking and she knew the whole time, you know, she had told me, "something's wrong with alexia's brain." she knew. >> reporter: so in a weird way, she wasn't even blaming her sister. >> no. she had this connection. and she was telling me, "something happened. because this is not my sister." you wanna try it? >> no! no! >> reporter: alexia herself knew something was wrong too. >> what are you doing! >> she would cry and say, "mommy, why can't i be good? i just want to be good." and, that broke my heart. >> reporter: you would start taping episodes. why?

>> he wasn't home a lot. so he wasn't seeing it. a lot of times, he was discounting it. >> at the beginning, i'm at work, working 50, 60 hours a week. i can't be on the phone with you for an hour talking to you every day to help you deal with these situations. before i really recognized what it was, that it wasn't something that she could deal with alone. >> reporter: three months of relentless emotional anguish. then a simple run for milkshakes becomes the final straw. >> hi, how can i help you? >> can i have three small shamrock shakes? >> reporter: vanessa takes her girls on a seemingly routine treat, until alexia insists on seconds. >> she said, "mommy, give me your milkshake." and i said, "no, alexia."

and then, she counted, "one, two, three." and then, i heard a click. >> reporter: the toddler unbuckles her car seat and starts rummaging through her mother's purse. >> as i picked my head up, she was stabbing me in the eye with my mascara wand. i was scared. i was scared for all of our safety. this isn't normal you know, 4-year-olds don't unbuckle their seat belts in the car to stab their mommy in the eye with a mascara wand all over a milkshake. >> reporter: you weren't sure if you could get home safely. >> i wasn't, no. i didn't feel that i was safe, that kayla was safe, or that alexia was even safe from herself. >> reporter: out of options, the desperate parents finally do what for them had been unthinkable. you had to put your 4-year-old in a psych ward. >> the hardest nine days of my life. we could only see her for an hour a day. she was allowed to call us once a day.

>> reporter: an hour a day for a 4-year-old? >> for a 4-year-old, those phone calls that she got once a day, she spent crying to me, "why did you leave me? i need you. i need you to come back." >> reporter: after those excruciating nine days in the psych ward, she had only a plethora of prescription drugs to show for it. did the drugs work? >> no. no, they made her, like, a shell of her person. when she was on this medication, all that happiness was gone. >> reporter: when "20/20" continues, someone else is suffering from the same strange sickness, and it's all on home video too. but unlike alexia, this child is suffering in silence. >> come back to me parker. are you there? look at mom. >> reporter: what's the connection? >> we had a neuropsychological evaluation done. she asked, "is there anything else that you think i should know?" i said, "well, she also had strep right before this all happened."

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>> reporter: spring came late to minnesota this year -- the land of 10,000 lakes still frozen. long past usual. but in the pleasant town of prior lake, april marked a year since the barnes family's lives changed forever. >> before all this hit, what was your family life like? >> four kids. two dogs. >> lots of love. lots of laughs. lots of giggles.

>> need to do truth or dare. >> what number is that? >> reporter: 11-year-old parker, the oldest in the top bunk. >> my nickname, that my mom and dad call me is lead dog, a rambunctious outgoing boy. >> reporter: until mid way through 4th grade, parker started acting differently. odd ticks, strange moodiness. >> are you all right, parker? >> deep breath, honey. deep breath, bud. >> reporter: but then something much worse. >> you're in control, honey. >> reporter: it's hard to watch. >> you're in control, parker. look at mom. >> reporter: harder still when you consider natalie and brian were watching their son suffer with seizures like these for months. >> are you there? look at mom. look at mom. where is mom at? you see her? >> reporter: heart wrenching and

without >> its okay, parker. we got you honey. we gotcha. i love you, parker. i'm with you, parker. >> i would liken it to an abduction. something came in the window and stole our child, and left behind this shell. our kid is gone! like, gone! >> die, die, parker. >> i was the first one to see it. >> reporter: but parker's brother witnessed one of the worst episodes one day while heading upstairs to the bathroom. he ran into parker brandishing a kitchen knife. >> i'm, like, dad, mom, he is going to stab himself! >> i ran up into the farm and there he stood with the knife in his hand. >> bawling uncontrollably. >> i just grabbed the knife and i'm just hugging him. >> reporter: that day with the

knife, did you want to hurt yourself? >> i don't really know. >> it's like you don't recognize your own child. i think he needs to be evaluated by a psychiatrist. >> reporter: it's a psychiatric condition? >> yeah. >> reporter: just like the baiers, the barnes's were dumbstruck to be checking their child into a psychiatric hospital. >> oh, that was a nightmare. >> that was a nightmare. >> that was, like, a prison for children, 'cause all the children didn't want to see their families, because they were all so, like, angry or mean or something. >> reporter: but while parker was being evaluated, suddenly, a curious coincidence. a doctor was struck when she learned that when parker's symptoms first began, all those months ago, he had just been diagnosed with something else -- strep throat. it was a "eureka" moment.

>> and she said, "he might have something called, pandas." and we're like, "pandas?" >> parents get the answer, "pandas." and their reaction is, "huh? pandas?" >> correct! >> reporter: if you've never heard of pandas, you're hardly alone. in fact, no one had heard of it. before this woman, dr. susan swedo, of the national institute of mental health, first identified it 20 years ago. >> i just study children and try to understand what's wrong with them and how to help them. >> reporter: while it conjures up images of the cute and cuddly bears, "pandas" is actually an acronym -- "pediatirc autoimmune nueropyschiatric disorders," associated with strep. >> what is pandas? >> in its simplest form, the wrong strep in the wrong kid impacts the brain and gives rise to behavioral symptoms. >> reporter: how? she says normally when children

get strep, their immune systems create antibodies to fight the infection. but with certain kids, the immune system malfunctions. those antibodies start attacking healthy cells. and even worse, they sneak across what's called the "blood brain barrier." >> it's designed to protect the brain? >> it's designed to protect the brain. we now know that the blood brain barrier can become "leaky." >> it's as if the antibodies are attacking the brain? >> in a way, yes. >> reporter: and once the brain is invaded, swedo says, that's when children can very rapidly exhibit a wide range of psychiatric and neurological problems, some as severe as the kind both parker and alexia have. >> so, traditional onset ocd is gradual, comes over a period of days or weeks. pandas ocd comes on overnight. >> a medical lightning strike? >> a, lightning strike, that's right. >> the only thing that i kept questioning is, but why did this suddenly come on? wouldn't i have seen signs?

and what about that strep? >> her research and striving to figure it out really, really paid off. >> reporter: eventually, a neuro-psychologist made a connection between the strep and immediate onset of symptoms that made sense to the baier family. >> then she was like, "okay, have you every heard of pandas?" >> is is fair to say you were relieved? >> definitely relieved to have some sort of diagnosis that made sense. >> and im thinking, "great. good -- pandas." >> whatever "pandas" is. >> is there a syrup for that? >> i know, exactly! >> what do you do? they're gonna have the right thing, the anti pandas pill and whatever that is, it'll be gone and we'll be down the road and we get our kid back? >> reporter: coming up -- it turns out that road is loaded with land mines. the kind that can tear a family apart. >> what toll did this take on your marriage? >> reporter: stay with us.

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>> you think that's our plane? >> probably. >> reporter: natalie barnes and her son parker are heading to our nation's capitol. >> you want to wear the child's mask or the adult mask? >> reporter: they could have all kinds of stuff on the plane. >> reporter: they are making a 1,200-mile pilgrimage, not for the sight-seeing, but to see one of the country's mavens of the medical field. >> what's it like to be able to actually help the family that's been so desperate for so long? >> well i don't think there's many greater rewards than that really. >> reporter: meet dr. beth latimer, a firebrand pediatric neurologist with a months-long waiting list. she takes the pandas cases many other doctors won't. >> i have felt tremendous amount

of responsibility for these kids. you see people move from, like, one side of the country to the other. parents get divorced because they can't deal with the trauma of this illness. >> there you go. good job. >> reporter: latimer started seeing pandas patients 15 years ago and quickly became a last resort for parents who believe a simple strep throat stole their children. parents like natalie and her husband brian, who took parker to more than a dozen doctors in their home state of minnesota looking for a panacea for pandas all with limited results. >> i would have to say most of the time i would bring it into these doctor appointments and they would go hmmm. that's interesting. that's weird. >> nobody ever said oh, my god, i can't believe he's doing that, lets figure that out. >> thank you for flying with us. we should be on the ground shortly. >> reporter: that is, until they went to see dr. latimer in dc.

mom and parker walk in the building. >> she goes by beth. >> hi there. doctor latimer this is parker. >> hi parker. okay, so the first thing i want you to do is look right at my nose, okay? >> reporter: dr. latimer spends over two hours evaluating parker medically. >> now turn your head over towards the window. >> reporter: learning his developmental history >> this was his cursive, and you can see it almost looks like. >> perfect. >> and then instead of cursive he started printing, and then his printing started to look more like, even before kindergarten. >> reporter: but most compelling, visual evidence dr. latimer gets to see is this. the dramatic, at times disturbing, home video the barnes's took to document their son's ordeal. >> come on. you can do it, son. >> is that the seizure? that's so scary.

>> his eyeball's twitching. >> what made i start recording? >> because i couldn't believe it was happening, because i wouldn't have believed it myself if i told myself. >> this is so bizarre. it's like a short circuit in his brain. >> reporter: behavior ranging from unresponsive. >> that was him he's just catatonic. he's lost somewhere else. >> reporter: to full-on rage. >> hold it together, parker. he is starting to wig and he knows it. >> reporter: moaning, whining -- >> get away. stop talking and leave. you're all going to kill me eventually, i know it. >> parker. >> reporter: he eventually stopped talking altogether. >> this was the day he spent four hours pushing himself on the floor. >> that is so disturbing. >> it's like this. he would just freeze up. not all the time but that's a good example. >> would he respond if you talked to him? >> nope. he would not respond. >> okay.

>> and he would have those almost every day. >> it's okay, parker. i got you. >> so, does he have pandas? >> does he have pandas? >> he has pandas. >> he has pandas. >> reporter: dr. latimer says she knows pandas when she sees it. >> [ bleep ] you people. >> reporter: which comes as a relief to some parents who say their doctors only told them their kids were crazy. >> every day for me was trying not to cry. >> what made you want to cry? >> you see a child, you know, robbed of their life. there is nothing quite like it. >> reporter: tim sorel isn't a doctor, he's a filmmaker, who tapped into a robust and vibrant network of pandas parents for his documentary "my kid is not crazy." >> he would literally scream bloody murder like a terror cry, not just a 'i'm not getting my way' cry, but terror in his face. >> reporter: seven sets of parents funneled their harrowing home videos to sorel, hoping he could connect the dots between what started as

strep and ended like this. >> i would get terrible phone calls in the middle of the night. they're desperate. they're truly desperate. >> what do they ask you in the middle of the night? >> what do you think i should do next? where can i turn? what have you heard? >> he was completely dysfunctional. he would urinate on himself. he was completely overwhelmed with rituals. >> reporter: one of the most unusual and curious cases in sorel's film? katherine ulicki. >> this is not my daughter. the way she was like a couple weeks ago, who as a 9-year-old suddenly started exhibiting bizarre behavior of her own. >> reporter: not screaming fits or convulsions, but rather an aversion to eating. >> i promise you guys if i had to eat this there would be an allergic reaction. >> to an apple. >> yes, really i promise you. i promise i would have an

allergic reaction. >> reporter: one day, she stopped eating altogether. >> what did you think of this? >> i had no idea what was going on. >> you can do it. you can do it. >> i was so close. >> reporter: kathryn, who hardly resembles her younger self today, was mystified too. >> you weren't like oh, my god, i have to lose weight? >> no, i was like so far from that fact i would get so scared, like i thought my parents were poisoning me. >> reporter: kathryn had had a long standing allergy to sesame, but this level of paranoia was brand new. because you wanted to eat? >> yeah. >> reporter: you wanted to drink? >> yeah. >> reporter: and yet you just couldn't? >> yeah. >> i was like scared to swallow my own saliva. so i would just spit the whole entire day. >> reporter: what were you afraid of by swallowing? >> like i would have an allergic reaction. >> reporter: to your own spit? >> mm-hmm. >> reporter: she ended up in a hospital, being fed through a tube in her nose. >> look what they did to me today.

this. >> reporter: but things only got worse. >> you don't go from zero to crazy in that short a period of time from a perfectly normal kid. >> one day i was like crying to my dad and i was like i want to die. >> that's just heartbreaking. the idea of a 9-year-old girl wanting to end it all. >> its hard to put into words you're just second by second, minute by minute. >> while you're frozen in fear. >> reporter: what was the thing you're afraid of? >> my kid's going to die. >> reporter: coming up -- >> hi, catherine how are you, i'm dr. latimer. >> hi. >> reporter: both katherine and parker think they've found their lifelines. but some think dr. beth latimer is out on a limb. >> reporter: there are some people who think, maybe we are going overboard on the treatment. could this all be junk science? you're skeptical that pandas exists. >> yes. >> reporter: deeply skeptical. >> yes. >> reporter: and others that cast blame on the parents. >> all because his parents shopped around for a doctor. willing to blame kevin's neurologic tics on strep instead of admitting they likely passed it on to him genetically.

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>> reporter: even for dr. latimer, kathryn ulicki's case was unusual. >> kathryn actually surprised

me. she came and she couldn't swallow anything. she was spitting into a cup and drooling constantly. >> reporter: she was confident she could help. but dr. latimer's proposed solution sounds startling. in addition to heavy duty antibiotics, she wanted to put kathryn on steroids, believing the injections would suppress her immune system which had gone haywire. >> i don't know how you're gonnna do with the steroids. but i'm telling you, you're not going to your prom like this. >> reporter: dr. latimer says she had seen it work before. but still, giving steroids to a 9-year-old girl? >> when we were with dr. latimer, i remember thinking of her like a gladiator. >> reporter: why a gladiator? >> because it's a disease that needs to be slayed. >> reporter: but what you'll find if you google p.a.n.d.a.s., is that there's a long-standing controversy that parents say is throwing roadblocks in the road to recovery. >> we have a huge problem with children not getting appropriate care. >> reporter: remember dr. susan swedo from the national institute of mental health? she says doctors like herself and dr. latimer aren't considered gladiators, but rather renegade cowboys.

because so many other doctors refuse to believe p.a.n.d.a.s. is a real disorder. so they dismiss it? >> they dismiss it. >> reporter: or they want more proof. you're skeptical that p.a.n.d.a.s. exists. >> yes. >> reporter: deeply skeptical. >> yes. i think the majority of those who believe they have p.a.n.d.a.s. just have regular old ocd or regular old tics. >> reporter: dr. donald gilbert, a neurologist at cincinnati children's hospital, studied this for seven years and says his own research, as well as others, has yet to prove strep causes ocd, tics or other psychiatric or neurological conditions in children. where do you think the medical establishment is on p.a.n.d.a.s.? >> i think child neurologists are almost uniformly skeptical. i think at most this is a very, very rare condition. >> no. it's not rare. i think that the disorder is uncommon. it probably affects somewhere between 1 in 201

year. >> reporter: 1 in 200 is a huge number of children potentially. >> it is. in the country as a whole, it's far, far under recognized and under treated. >> it's very different to say, there's a few kids that have this versus saying that maybe 10% of ocd cases are caused in this way. >> reporter: so you're saying it's over diagnosed? >> way over diagnosed. >> reporter: swedo says she's been attacked for her p.a.n.d.a.s. theory and faced an onslaught of published opposition in medical journals. >> i'm going to read to you an e-mail. >> reporter: we read dr. swedo what another p.a.n.d.a.s. skeptic told "20/20." i think the bear has died. the original concept that patients can present with typical tourette's syndrome or ocd due to an autoimmune response to strep infection has largely been dismissed. the whole concept is very tenuous now. >> oh, dear. >> reporter: what is your reaction to that? >> it is one man's opinion. and he is wrong. he is just wrong. like a drum beating. it just won't stop. maybe like in politics, if you repeat a lie often enough it's construed to be the truth.

so the physicians have been afraid. >> reporter: caught in the middle of all this medical infighting? sick children and their frenzied parents. >> you're so [ bleep ] tired. every day, to read papers and understand stuff and talk to [ bleep ] doctors and say, "well, you know, listen, figure it out." i'm too [ bleep ] tired to read this [ bleep ] and explain it to you. just do something for my kid, you know. do something. >> reporter: tim sorel saw both sides of the fight making his film. >> you have -- these are our numbers. these are swedo's numbers. now you have a controversy. >> reporter: how often do you have to confront skepticism? >> often. you even find it on tv shows and on facebook. >> reporter: tv shows like the drama "chicago med." >> is there any other medical history we should be aware of? >> yes, he's been diagnosed with p.a.n.d.a.s. >> p.a.n.d.a.s.? >> reporter: that featured p.a.n.d.a.s. in this episode. >> and all because his parents shopped around for a doctor, willing to blame kevin's neurologic tics on strep, instead of admitting that they most likely passed it on to him genetically.

>> that right there -- that was an attack on me and all the other families that have fought to actually help their children. it hurts as a mom. >> reporter: yet the respected american academy of pediatrics also remains unconvinced saying there is insufficient proof that strep causes the symptoms. it's only treatment recommendation? send patients to a specialist. >> this is all of parker's medical records. >> reporter: oh, my gosh. parents tell us this leaves much of the medical community unsure what to do and families like the barnes's in the lurch. and you have to bring this with you to every new doctor? especially because ior unconventional treatments which, in parker's case, have run close to $50,000. >> you submit to the insurance company. you say, "pretty please." and they tell you, "no. it's considered experimental." >> i mean, its brutal. there's just no other way to describe it. >> reporter: which brings us back to dr. latimer and her bold

idea for getting parker well. >> you've the strep out of the house. i would do plasmapheresis. >> reporter: plasmapheresis, a name as scary as it is invasive. a kind of dialysis for the blood. the goal -- get the problematic antibodies out. the problem, it requires five days in intensive care and comes with risks including seizures. >> you need an icu. you need someone to sedate the child, put the line in, and then a hematology-oncology team to run the process. that's what you need. so, that's what i would do next. he'll be okay. >> because that's what i really want. thank you for being a cowboy. thanks for being -- just standing up above the grade. because it's not easy. >> reporter: p.a.n.d.a.s. is complicated. >> it's difficult. it's dirty. you're in the mud. people yelling at you, criticizing you. you gotta be able to take the slings and arrows. >> reporter: but it turns out, sometimes, there are happy endings.

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>> reporter: it's not an unusual sight for summer. a couple of tweens, an ice cream parlor and a double scoop of salty pretzel. except, this would have been unthinkable three years ago. kathryn ulicki was hospitalized, unable to eat. when dr. latimer started her on those steroid treatments, remarkably, within two weeks, an amazing result.

>> all right. how does that taste? >> that went down! >> i know it did. >> that was a big one, too. >> reporter: she was eating again! >> this is strawberry? i think so. >> reporter: almost as fast as the disorder began, it was gone. >> i think we are still in shock or slowly coming out of shock. i don't think we are out of it yet. i'm not sure we ever will be, really. >> reporter: what's her prognosis at this point? >> excellent. >> reporter: totally normal life? >> yes. >> reporter: from then on, it was teeny bopper business as usual. >> gosh, she was doing fabulous, loving school, playing softball --just getting back to baseline. >> i feel, like, a lot better today, like emotionally and physically. >> reporter: what's it like

having your daughter back? >> you know, it's amazing, really, considering where she came from. >> it's kind of nice now. in a way, there's times i forget about p.a.n.d.a.s. >> reporter: kat has a happy ending. >> kat does have a happy ending. you know, it was wonderful to see. again, i want to emphasize we don't know what got her better. but who cares what got her better, as long as she did. >> reporter: at least one p.a.n.d.a.s. skeptic thinks kids may simply outgrow the symptoms. >> i think as a general principle, over time, many things get better. >> reporter: so, you think they get better on their own? >> yeah, it's quite possible. i don't know for sure, but that does happen. >> reporter: but back in miesot his case is still precarious. >> i felt in my heart that parker's a very severe case. and that he's gonna need the biggest punch that we can find. >> reporter: natalie and brian barnes had every intention

of putting parker through the extreme treatment dr. latimer had suggested -- plasmapheresis, scary cleansing of his immune system. >> parker suffers every day. he has no childhood right now. it's like, if you had a child that was told they had leukemia. and they had to be hospitalized to get chemotherapy. you would not hesitate. >> reporter: but remember that diagnosis -- p.a.n.d.a.s. -- is controversial. and that treatment for it -- unconventional. not all doctors accept it, including, as the barnes were shocked to find out, their local immunologist. >> he said, "i will not participate on any level with your son if you give him that treatment." "i don't agree with it. and i won't touch him." >> reporter: and with that, plasmapheresis was out. >> it just wasn't possible. it just didn't happen. >> the logistical problem of trying to get it arranged was confounding. >> reporter: so now what? >> there's a million ways. and i think it depends on what your doctor considers serious, what they're comfortable ordering.

>> reporter: instead, the barnes' local immunologist increased the frequency of parker's medication, steroid treatments and injections to boost his immune system. >> reporter: and lo and behold, his parents say, as parker turned 12 in june, it actually seemed to be working. it even led to this, a very different home video of parker playing with his siblings and go cart rides. but, just a few weeks ago, they told us parker's p.a.n.d.a.s., in all its confounding and capricious patterns, reared its ugly head again. >> he had moments where he would be ok. and then he would just dive down to a point we hadn't seen. it's not in the uncomfortable place.

it's back in the scary places where he's become very unpredictable. >> die, suffer, bleed. die, suffer, bleed. >> he would sit there and chant, die, suffer, bleed. die, suffer, bleed. >> die, suffer, bleed, die, suffer, bleed. >> i should just be suffering. i should make myself bleed. as a parent, panic can set in very quickly. >> reporter: parker's future tonight remains uncertain. the barnes's say yet another specialist in their area may be willing to perform a plasmapheresis. but it could cost as much as $100,000 when all is said and done. >> some people have said that p.a.n.d.a.s. is a rich man's disease. 'cause it takes a rich person to get their kid better. >> reporter: still ahead, history is made when one of these children's families score a victory on the war against p.a.n.d.a.s.

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>> announcer: we continue now with more of "20/20." >> reporter: pandas success stories are hard to come by. but if one exists, it's alexia baier's. now 8 years old, she's back

to rough housing with her sister and just finished a banner second grade. >> she was chosen out of her entire school as the student of the month for positive behavior. >> that's incredible. >> it is, yeah. >> so the child who is tantruming and trashing her preschool is student of the month? >> yes. exactly. >> reporter: the baiers say it's all thanks to that doctor who believed. >> they gave her an antibiotic and almost like a light switch again, she was better. >> reporter: just like with those other kids, the baiers say it was a combination of antibiotics, steroids and other behavioral therapies which led to alexia's recovery. but flare ups still occur about every few months. something as simple as the common cold virus can trigger them. >> it's as if her immune system doesn't quite know what to do. >> right. >> it's not a straight-line recovery, is it? >> no. and i foresee that we'll still have our bumps in the road. that's part of the hard thing with pandas.

it's not one size fits all. >> reporter: tonight, there are different baier family portraits they wanted us to share. last week, the couple celebrated their ten-year wedding anniversary by renewing their vows. >> what toll did this take on your marriage? >> again, at the beginning, i didn't believe her, so it was like, deal with it. now looking back, it's one of those things that had i been there and seen it earlier, i might have been more -- might have been more understanding and recognized that it wasn't something that she could deal with alone and shouldn't have to. >> just the fact that you're able to acknowledge that now goes a long way, i suspect. >> yes. >> i hope. >> reporter: and score one more unqualified victory for the baier family, one they may have helped bag for an untold number of pandas patients. >> a bill is now being introduced in springfield, this week. >> reporter: vanessa, along with other parents, lobbied the illinois state legislature to

force insurance companies to cover pandas treatments. >> i had talked to a representative, and i told him how my daughter had suicidal thoughts. this is my child's life in your hands. >> reporter: the politicians listened and just last july, the bill, the only one of its kind, passed. >> why did the governor symbolically sign it at a kitchen table? >> to show that this is affecting pandas' families. that this is a family disease. i really think that it's not just the child who suffers with pandas, it's the entire family, and this could happen at anybody's kitchen table. >> love you. have fun. be good. bye. >> certainly a happy ending for some families. what you saw tonight were extreme forms of pandas and by no means does every child with strep go on to form any form of

pandas. >> that's reassuring how alarming this is. even if you notice behavioral changes, it doesn't mean they have pandas. the best thing to do is check with your own doctor if you have any questions. we'll have much more later tonight o oon "nightline." >> if you have questions, go to our website. i'm amy robach. >> i'm david muir. thanks for watching. good night.

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