FV 513. A Potential Risk of Inadequate Prognosis in Hypothermic Children after Asphyxia with Delayed Abnormalities in Diffusion-Weighted Images

Background: It is known in newborns after severe perinatal asphyxia that during hypothermia of 33°C evolution of abnormalities in diffusion-weighted imaging (DWI) might be delayed. In infants and children, these phenomena are less well described. There is lack of knowledge how mild hypothermia between 34 and 35°C might impact the evolution of DWIs abnormalities in children beyond neonatal period.

Aim: We present two infants who suffered severe asphyxia and showed minimal DW abnormalities during phase of mild hypothermia (34–35°C) despite later on proven severe ischemic damage.

Question: Accuracy of DWI performed early in hypothermic children after asphyxia.

Methods: Case 1: A 10/12-year-old boy suffered severe asphyxia due to accidental suffocation. There was active resuscitation for 17 minutes and the boy was transferred to our intensive care with a body temperature of 34.5°C and clinical signs of coma. First magnetic resonance imaging (MRI) 7 hours after the event showed mild DWI abnormalities in globus pallidus, corpus callosum, and cortically–subcortically occipital abnormalities. Clinically, the child showed persistent severe neurological deficits with absence of brain stem and cranial reflexes except for a slow pupil response to light. A repeat MRI 2 days later with normal body temperature in the boy showed severe signal DWI alterations in basal ganglia, thalamus, occipital, and parietal lobes bilateral.

Case 2: Female infant was born after normal pregnancy by an uncomplicated spontaneous vaginal delivery and discharged home on day 3. During the first 2 weeks, the infant suffered upper respiratory infection with increasing symptoms. She was found by her mother without breathing in the crib. Immediate resuscitation was performed and the child was referred to our intensive care unit with active heart function on mechanical respiration. Clinically, she was severely depressed, showed partially abolished brain stem reflexes, and was kept on low temperature of 34°C. MRI 10 hours after the event showed mild signal alterations in hippocampus, dentate gyrus, and dorsal pons bilaterally. She did not recover from severe clinical symptomatology and a follow-up MR after 48 hours with normal body temperature showed severe DWI signal alterations in both thalami with transition to the capsula interna bilaterally.

Results: Due to persistent severe clinical condition accompanied by these severe ischemic lesions in MR decision for withdrawal of support was taken in both cases. The boy died a few minutes and the girl within 1 hour after extubation.

Conclusion: Similar to newborns with hypothermia at 33°C, in infants after severe asphyxia and mild hypothermia around 34 to 35°C signal alteration in DWI within the first few hours after the event might not show the real extent of ischemia as would be expected in case of normal body temperature. Thus, in case of missing clinical improvement within the next 24 to 48 hours, a second imaging might be indicated to take decisions on life support.