Therapeutic Hypothermia May Reduce Seizure Risk in Neonates With Stroke

Among neonatal patients with stroke and encephalopathy, seizures may cause a decline in cognitive outcomes. Therapeutic hypothermia may reduce seizure risk in these patients.

SAVANNAH, GA—Therapeutic hypothermia may reduce the risk of seizures in neonates with stroke who also have encephalopathy, according to research presented at the 40th National Meeting of the Child Neurology Society. The research also suggests that seizures may result in diminished cognitive outcomes in these patients.

Mary J. Harbert, MD, Assistant Clinical Professor at the University of California, San Diego, told Neurology Reviews that although the underlying mechanisms allowing therapeutic hypothermia are not definitively known, “One theory for the anticonvulsant effect of hypothermia is that hypothermia reduces cellular metabolic demand, and a seizing neuron is ‘metabolically greedy’ compared to a normal neuron.  Seizures, especially in newborns, drive down glucose levels in the brain, and hypothermia may ameliorate this by making seizing neurons use less energy.”

Therapeutic Hypothermia and Neonatal Stroke
Dr. Harbert and colleagues performed a nested case-control study within a single-center prospective cohort study of neonatal encephalopathy, which took place from 1994 to 2010 and included 315 patients with neonatal encephalopathy. The researchers examined seizure occurrence, neurodevelopmental outcome, and the effect of therapeutic hypothermia in perinatal stroke presenting with encephalopathy.

Using MRI, the study authors determined that 15 of the 315 participants had experienced focal stroke. These 15 focal stroke cases were matched, based on gender and degree of encephalopathy, to 30 control neonates from the same cohort who did not display MRI evidence of stroke.

Of the 15 study participants with focal stroke, five received therapeutic hypothermia and 10 did not. None of the five participants treated with hypothermia had seizures in the neonatal period. However, seven of the 10 participants who did not undergo hypothermia experienced seizures in the neonatal period.

“Hypothermia was associated with significantly decreased risk of seizures in the neonatal period,” the researchers stated. “This is the first human study to demonstrate a potential treatment effect of therapeutic hypothermia on perinatal stroke.”

Evaluating Cognitive Outcomes
In addition, Dr. Harbert’s group assessed cognitive outcomes of neonates with stroke presenting with encephalopathy. Using the Bayley Scales of Infant Development to calculate Mental Development Index scores, they found that patients with stroke and encephalopathy had scores that were an average of 26.21 points lower than the scores of control group patients with encephalopathy but without stroke. However, after adjusting for neonatal seizures, this association was not significant.

The study authors concluded that “neonatal seizures adversely affect cognitive outcomes in stroke presenting with encephalopathy when compared to non-stroke encephalopathic controls. This suggests that the effect of neonatal seizures upon cognitive outcomes may be dependent upon seizure etiology.”

Continuing Research Is Necessary
While these results may eventually contribute to new treatment approaches, Dr. Harbert does not recommend changing clinical suggestions for neonates with stroke and encephalopathy based on her study alone. “Hypothermia is already being studied in adults with stroke.  I would like to see similar studies done in neonates who present with acute stroke,” she said.    

Among neonatal patients with stroke and encephalopathy, seizures may cause a decline in cognitive outcomes. Therapeutic hypothermia may reduce seizure risk in these patients.

SAVANNAH, GA—Therapeutic hypothermia may reduce the risk of seizures in neonates with stroke who also have encephalopathy, according to research presented at the 40th National Meeting of the Child Neurology Society. The research also suggests that seizures may result in diminished cognitive outcomes in these patients.

Mary J. Harbert, MD, Assistant Clinical Professor at the University of California, San Diego, told Neurology Reviews that although the underlying mechanisms allowing therapeutic hypothermia are not definitively known, “One theory for the anticonvulsant effect of hypothermia is that hypothermia reduces cellular metabolic demand, and a seizing neuron is ‘metabolically greedy’ compared to a normal neuron.  Seizures, especially in newborns, drive down glucose levels in the brain, and hypothermia may ameliorate this by making seizing neurons use less energy.”

Therapeutic Hypothermia and Neonatal Stroke
Dr. Harbert and colleagues performed a nested case-control study within a single-center prospective cohort study of neonatal encephalopathy, which took place from 1994 to 2010 and included 315 patients with neonatal encephalopathy. The researchers examined seizure occurrence, neurodevelopmental outcome, and the effect of therapeutic hypothermia in perinatal stroke presenting with encephalopathy.

Using MRI, the study authors determined that 15 of the 315 participants had experienced focal stroke. These 15 focal stroke cases were matched, based on gender and degree of encephalopathy, to 30 control neonates from the same cohort who did not display MRI evidence of stroke.

Of the 15 study participants with focal stroke, five received therapeutic hypothermia and 10 did not. None of the five participants treated with hypothermia had seizures in the neonatal period. However, seven of the 10 participants who did not undergo hypothermia experienced seizures in the neonatal period.

“Hypothermia was associated with significantly decreased risk of seizures in the neonatal period,” the researchers stated. “This is the first human study to demonstrate a potential treatment effect of therapeutic hypothermia on perinatal stroke.”

Evaluating Cognitive Outcomes
In addition, Dr. Harbert’s group assessed cognitive outcomes of neonates with stroke presenting with encephalopathy. Using the Bayley Scales of Infant Development to calculate Mental Development Index scores, they found that patients with stroke and encephalopathy had scores that were an average of 26.21 points lower than the scores of control group patients with encephalopathy but without stroke. However, after adjusting for neonatal seizures, this association was not significant.

The study authors concluded that “neonatal seizures adversely affect cognitive outcomes in stroke presenting with encephalopathy when compared to non-stroke encephalopathic controls. This suggests that the effect of neonatal seizures upon cognitive outcomes may be dependent upon seizure etiology.”

Continuing Research Is Necessary
While these results may eventually contribute to new treatment approaches, Dr. Harbert does not recommend changing clinical suggestions for neonates with stroke and encephalopathy based on her study alone. “Hypothermia is already being studied in adults with stroke.  I would like to see similar studies done in neonates who present with acute stroke,” she said.    

Among neonatal patients with stroke and encephalopathy, seizures may cause a decline in cognitive outcomes. Therapeutic hypothermia may reduce seizure risk in these patients.

SAVANNAH, GA—Therapeutic hypothermia may reduce the risk of seizures in neonates with stroke who also have encephalopathy, according to research presented at the 40th National Meeting of the Child Neurology Society. The research also suggests that seizures may result in diminished cognitive outcomes in these patients.

Mary J. Harbert, MD, Assistant Clinical Professor at the University of California, San Diego, told Neurology Reviews that although the underlying mechanisms allowing therapeutic hypothermia are not definitively known, “One theory for the anticonvulsant effect of hypothermia is that hypothermia reduces cellular metabolic demand, and a seizing neuron is ‘metabolically greedy’ compared to a normal neuron.  Seizures, especially in newborns, drive down glucose levels in the brain, and hypothermia may ameliorate this by making seizing neurons use less energy.”

Therapeutic Hypothermia and Neonatal Stroke
Dr. Harbert and colleagues performed a nested case-control study within a single-center prospective cohort study of neonatal encephalopathy, which took place from 1994 to 2010 and included 315 patients with neonatal encephalopathy. The researchers examined seizure occurrence, neurodevelopmental outcome, and the effect of therapeutic hypothermia in perinatal stroke presenting with encephalopathy.

Using MRI, the study authors determined that 15 of the 315 participants had experienced focal stroke. These 15 focal stroke cases were matched, based on gender and degree of encephalopathy, to 30 control neonates from the same cohort who did not display MRI evidence of stroke.

Of the 15 study participants with focal stroke, five received therapeutic hypothermia and 10 did not. None of the five participants treated with hypothermia had seizures in the neonatal period. However, seven of the 10 participants who did not undergo hypothermia experienced seizures in the neonatal period.

“Hypothermia was associated with significantly decreased risk of seizures in the neonatal period,” the researchers stated. “This is the first human study to demonstrate a potential treatment effect of therapeutic hypothermia on perinatal stroke.”

Evaluating Cognitive Outcomes
In addition, Dr. Harbert’s group assessed cognitive outcomes of neonates with stroke presenting with encephalopathy. Using the Bayley Scales of Infant Development to calculate Mental Development Index scores, they found that patients with stroke and encephalopathy had scores that were an average of 26.21 points lower than the scores of control group patients with encephalopathy but without stroke. However, after adjusting for neonatal seizures, this association was not significant.

The study authors concluded that “neonatal seizures adversely affect cognitive outcomes in stroke presenting with encephalopathy when compared to non-stroke encephalopathic controls. This suggests that the effect of neonatal seizures upon cognitive outcomes may be dependent upon seizure etiology.”

Continuing Research Is Necessary
While these results may eventually contribute to new treatment approaches, Dr. Harbert does not recommend changing clinical suggestions for neonates with stroke and encephalopathy based on her study alone. “Hypothermia is already being studied in adults with stroke.  I would like to see similar studies done in neonates who present with acute stroke,” she said.