Acute anemia linked to silent strokes in children

ScienceDaily (Feb. 12, 2011) — Silent strokes, which have no immediate symptoms but could cause long-term cognitive and learning deficits, occur in a significant number of severely anemic children, especially those with sickle cell disease, according to research presented at the American Stroke Association's International Stroke Conference 2011.

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One-quarter to one-third of children with sickle cell disease have evidence of silent strokes in their brains, according to Michael M. Dowling, M.D., Ph.D., lead author of the study and assistant professor of pediatrics and neurology at the University of Texas Southwestern Medical Center in Dallas.

"These are 5- to 10-year-old children who have brains that look like the brains of 80-year-olds," Dowling said. "These strokes are called 'silent' because they don't cause you to be weak on one side or have any obvious neurologic symptoms. But they can lead to poor academic performance and severe cognitive impairments."

Sickle cell disease is a blood disorder characterized by low levels of hemoglobin, the iron-containing component of red blood cells that carries oxygen. Low hemoglobin causes anemia. In sickle cell disease, the blood cells are misshapen (sickle-shaped) and may form clots or block blood vessels. About 10 percent of children with sickle cell disease suffer a stroke. Blood transfusions can reduce the high risk of repeat strokes.

Dowling and colleagues hypothesized that silent strokes occur during severe anemia and may be detectable by MRI. They used MRI on the brains of 52 hospitalized children 2- to 19-years-old at Children's Medical Center Dallas with hemoglobin concentrations dropping below 5.5 g/dL. They compared severely anemic children with sickle cell disease to a group of children without sickle cell disease who had hemoglobin levels below 5.5 g/dL.

They identified silent strokes in about 20 percent of the children with sickle cell disease who were experiencing acute anemia. They also saw evidence of silent strokes, though not as often, in severely anemic children who didn't have sickle cell disease.

The many reasons, besides sickle cell disease, why children could have anemia include trauma, surgery, iron deficiency or cancer such as leukemia.

"These are brain injuries that go unnoticed by doctors, unless the children have testing with a special MRI," he said. "We looked at every child who went to the hospital for a 30-month period and identified about 400 children that came in with hemoglobin below 5.5 g/dL. That represented about 12 percent of the admissions for sickle cell disease and about 1 percent of the total admissions to Children's Medical Center."

The findings suggest that children with or without sickle cell disease who have acute anemia could be suffering undetected brain damage. The researchers suggest that all children with severe anemia need careful examination for silent strokes.

Improved recognition and timely transfusion to increase blood hemoglobin levels could prevent permanent brain damage in children with silent strokes, according to the study.

Future studies should look at larger groups of children for longer periods to better understand the impact of acute anemia on children, Dowling said.

Co-authors are: Charles T. Quinn, M.D., M.S; Patricia Plumb, R.N., M.S.N.; Zora R. Rogers, M.D.; Nancy Rollins, M.D.; Korgun Koral, M.D.; Robert Barber, Ph.D. and George R Buchanan, M.D.

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CT scans are frequently unnecessary after head injury in children, large study finds

ScienceDaily (May 9, 2011) — Overall, roughly half of U.S. children taken to hospital emergency departments (EDs) for a head injury receive a head CT scan, often to ease worried parents' concerns. Yet true traumatic brain injury is uncommon. A multi-center study of more than 40,000 children with minor blunt head trauma, led by Children's Hospital Boston and UC Davis, shows that allowing a period of observation can reduce the use of head CT by as much as half without compromising care -- and without exposing children to ionizing radiation.

See Also:Health & MedicineChildren's HealthAccident and TraumaInfant's HealthMind & BrainChild PsychologyBrain InjuryChild DevelopmentReferencePhysical traumaPediatricsHead injuryBrain damage

Results appear in the June 2011 issue of Pediatrics (published online May 9).

"Only a small percentage of children with blunt head trauma really have something serious going on," says Lise Nigrovic, MD, MPH, of Children's Hospital Boston, who co-led the study with Nathan Kuppermann, MD, MPH, chair of the Department of Emergency Medicine at UC Davis. "If you can be watched in the ED for a few hours, you may not need a CT."

This change in practice would not only be cost-saving, but is better medicine, the researchers say.

Nigrovic, Kuppermann and colleagues analyzed the outcomes of children presenting at 25 different emergency departments, as part of a large prospective study conducted by the Pediatric Emergency Care Applied Research Network (PECARN). Of 40,113 children whose records could be analyzed, 5,433 (14 percent) were observed before making a decision about CT use. Observation times varied, as did the severity of head trauma.

Overall, the children who were observed had a lower rate of CT than those not observed (31 vs. 35 percent). When the researchers matched the observed and non-observed groups for severity of head injury and the practice style of different hospitals, this difference was more pronounced: The likelihood of a CT scan in the observed group was about half that of similar non-observed patients (odds ratio, 0.53). In particular, children whose symptoms improved during observation were less likely to eventually have CT.

Allowing for an observation period did not compromise safety, the study found: Clinically important traumatic brain injury -- resulting in death, neurosurgical intervention, intubation for more than 24 hours or hospital admission for two nights or more -- was equally uncommon in the observed and non-observed groups (0.75 vs. 0.87 percent).

Nigrovic and Kuppermann note that cranial CT itself presents additional risks for children. Children's growing brain tissue is more sensitive to ionizing radiation than adults', and because of their longer life expectancy, their lifetime risk of developing a radiation-induced malignancy is greater.

"CT isn't bad if you really need, but you don't want to use it in children who are at low risk for having a significant injury," says Nigrovic. "For parents, this means spending a couple of extra hours in the ED in exchange for not getting a CT. It's the children in the middle risk groups -- those who don't appear totally normal, but whose injury isn't obviously severe -- for whom observation can really help."

The researchers were unable to determine the actual length of time the children were observed in the ED, a question they would like to investigate in the future. Practice guidelines from the American Academy of Pediatrics recommend a child be carefully observed for 4 to 6 hours after injury.

"There is a clear need to develop appropriate and safe guidelines for decreasing the number of inappropriate head CT scans that we do on children," says Kuppermann. "The results of this analysis demonstrate that a period of observation before deciding to use head CT scans on many injured children can spare children from inappropriate radiation when it is not called for, while not increasing the risk of missing important brain injuries."

Nigrovic offers the following general guidelines for parents whose child has a head injury:

Check with your primary care clinician before taking the child to the ED. If your child has headache, vomiting and/or confusion, or symptoms that worsen over time, an ED visit is appropriate. The ED clinician may reasonably choose to observe your child for several hours once you arrive before deciding about a head CT. The change of symptoms over time is an important factor in deciding whether to obtain a cranial CT.

The study was funded by the Health Resources and Services Administration/Maternal and Child Health Bureau, Division of Research, Training, and Education, and the Emergency Medical Services of Children Program.

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