After six weeks of hospitalization, 18 days in the ICU, countless blood transfusions, hemodialysis, intubations, a treatment-induced respiratory crisis and a bad bout of withdrawal from sedation, Charlotte Voss finally went home last week.

The 7-year-old's bout with a brutal form of E. coli was a lot of suffering for a Rochester third-grader who had never been sick.

It all started during an mid-July trip to her grandmother's house in tiny Falls City, Neb., population 4,325. The trip was her first time away from home without her parents, and a chance to swim in an above-ground pool. Then, just as her parents came to pick her up, Charlotte came down with a stomach ache.

At first the symptoms were run-of-the-mill. The cascade of trouble that followed proved to be anything but.

"The worst kept changing," says her mother Kathy. "First it was being admitted to the hospital. Then it was her going to the PICU. Then it was kidney failure."

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Your basic parent's worst nightmare: a healthy child thrust onto life support and her family propelled into bedside vigils, a crash course in bacterial infection and tearful worries over the return of basic organ functions. All for reasons unknown.

"We don't know where she got it," says Kathy Voss. "We can guess. Either from swimming in a pool and swallowing water, because my mom had treated it with chlorine but this bug laughs at chlorine, or a farm cat that was sick and was hanging around the yard."

"We named it Cocoa," said a soft-spoken Charlotte, coming to life at memory of the orphan cat that may just have sent her into acute renal failure. "It was very young, only a week old."

Everyone assumes E. coli is food-borne, says Kathy, because that's what you always hear about,

but Charlotte hadn't eaten the usual suspects (undercooked hamburger or processed lettuce).

"The biggest thing for us," says Kathy, "is we don't know, and we won't know, because it will make us crazy."

Test detected bacteria

Once in Nebraska, Kathy and her husband Justin took Charlotte to the local hospital when her stool became bloody in the middle of the night. "They kept saying it was a virus," said Kathy, "but then they did a test and it was.."

"..It was a bacteria," interjected Charlotte, curled up in her mother's arms.

The family dodged a bullet when the local hospital considered and then decided against giving Charlotte antibiotics, which can worsen the illness. But the worst was soon to come anyway.

The hospital admitted Charlotte and provided IV fluids as the small child's body became wracked by diarrhea in ten minute intervals.

But the small rural facility needed to send away for Charlotte's tests, a step unimaginable to the residents of Rochester. When they suggested transferring her to a critical care unit two hours away, her parents had Charlotte discharged, put their daughter in the car and with medical permission drove seven hours through the night back to Rochester.

The trip required rubber gloves and plastic bagging of all her clothes whenever she had an accident, but the family finally arrived at 3:40 am in Rochester, where a bed and team was waiting at Mayo Clinic Eugenio Litta Children's Hospital.

Like a bio-terror agent

Mayo determined Charlotte had become infected with the dangerous bacteria known as O157:H7 or STEC, for Shiga toxin-producing E. coli. The pathogen has a mechanism that works like the bio-terror agent ricin.

It attaches itself to the insides of the intestine, rupturing the lining and producing bloody stool before entering the blood stream, where it travels the body, attacking all in its path. There is no antidote, only system support while the body waits for the illness to leave by way of the digestive system.

Blood vessels are soon ravaged, primarily the kidneys but also those in the brain, intestines, everywhere else.

"This damage attracts platelets," said Dr. David Sas, a Mayo Clinic pediatric nephrologist who treated Voss during her month-long stay at Mayo. "They aggregate at sites of destructions and that causes the destruction of red blood cells. It's a bad disease."

"She went into kidney failure," says Kathy Voss. "She stopped urinating. When they told me what she had, it sounded so dire, I just thought, 'no way. She's so healthy.' I remember crying a great deal at that point."

"HUS is a very difficult disease," says Sas, referring to the secondary crisis that came next for Charlotte. Hemolytic Uremic Syndrome affects 20 percent of patients with STEC.

A rough road

"I've seen a fair amount of it in my career and I have a standard talk to help parents anticipate how rough the road will be," he says. "I's a really rough disease on kids and family."

That's putting it mildly. the body becomes a house of cards during HUS and Charlotte was destined to get one of the most severe courses of HUS imaginable.

Kidney failure caused her blood pressure to rise. Hemodialysis pulled fluid towards her vital organs, where it pooled near her heart and lungs.

The flash pulmonary edema caused by this development put her into the PIC-U, intubated, sedated and at risk of cardiac arrest and stroke. Removing the tube too fast caused a respiratory crisis.

"It was a very, very helpless feeling." said Kathy Voss. "You could tell it was serious by how many people were in the room."

A paralytic restraint was supposed to protect Charlotte from the experience of being intubated, but after waking up she remembered it all.

Taking her off sedation put her into drug withdrawal complete with terrors, hallucinations, frantic ripping at the leads attached to her body and itching -- all of it lasting for hours.

She finally turned around, which is the majority of outcomes in children with HUS. After a brief return to the hospital for severe high blood pressure, Charlotte finally went home last week.

"She's finally started making urine and her lab results look better," says Sas. "So I'm thinking she's on the road to recovery."

"She still has residual deficiencies in kidney function," he cautioned, and may have high blood pressure for some time, possibly all her life. (The kidneys release hormones that regulate blood pressure.) "Charlotte definitely kept us on our toes," he said.

"She's the same age as my daughter so it definitely hits home. But once she got better, let's just say she's an extraordinarily charming girl."

Charlotte wrote a note to her doctors and nurses, thanking them for her care, and telling them "we make a good team." She says other kids who find themselves in her situation should "keep fighting." And they should try to get sick, if they must, during the school year.

"I could have missed school instead of summer," she says. "But I liked the last day of school. We got to watch movies."