Blood test can reveal cause of brain injury in newborns, says study; highest disease burden in India

New Delhi: A simple blood test can pinpoint the underlying cause of brain injury in newborns which leads to a deadly condition with the highest disease burden in India, a study has found.

Hypoxic-ischemic encephalopathy (HIE) is a type of brain injury sometimes referred to as birth asphyxia, which occurs when a baby's brain does not get enough oxygen before or shortly after birth.

Globally, HIE is a leading cause of death and disability among babies born at full term, affecting about 3 million every year.

Following oxygen deprivation, brain injury can develop over hours to months and affect different regions of the brain, resulting in a variety of potential neurodisabilities such as cerebral palsy, epilepsy, deafness or blindness, the researchers said.

South Asia, and particularly India, has the highest disease burden, with the country accounting for 60 per cent of all HIE-related deaths in the world, they said.

The researchers from Imperial College London, UK, found that patterns of gene expression that are detectable in the blood can point to the cause of the injury and tell doctors if the newborn is likely to respond to cooling treatment, commonly used to treat brain injury in infants.

The findings, published in the journal JAMA Network Open, could eventually lead to a simple test to quickly diagnose brain injury in newborns and help with treatment decisions.

The study included babies from low and middle-income countries (LMICs) as well as high-income countries (HICs). There was a dramatic divergence in gene expression between the two groups suggesting a different underlying cause of brain injury.

"Although cases of brain injury in babies may appear similar, they can be quite different in terms of how they come about, as our study shows," said study lead investigator, Professor Sudhin Thayyil from the Imperial College London.

"The gene expression patterns we saw in babies from LMICs were similar to what you would see in people with sleep apnea, suggesting that they experienced intermittent hypoxia in the womb and at birth," Thayyil said.

The researchers believe this is brought on by multiple chronic stresses during pregnancy such as poor nutrition or infection, as well as the normal labour process and uterine contractions, which leads to further hypoxia and ultimately injury to the baby's brain.

On the other hand, gene expression patterns in babies from HICs suggested a single, acute cause of brain injury, for example complications during birth like maternal bleeding, leading to a sudden drop in blood oxygen levels in the fetus, they said.

Previous studies, mainly conducted in HICs, have shown that treatment with whole-body cooling can improve outcomes for babies with HIE. As result, it has become standard practice in many HICs, and is also used in some hospitals in South Asia.

However, in the largest study of its kind in low- and middle-income countries (LMICs), Thayyil and collaborators in India, Bangladesh and Sri Lanka previously showed that whole-body cooling actually worsened outcomes in babies with HIE and might have even increased mortality risk.

The new study helps to explain the reason behind this difference in treatment response between the two groups of babies and could eventually lead to a simple test to evaluate which babies are likely to benefit from cooling treatment.