Sonographic Changes in Hypoxic-Ischaemic Encephalopathy

Hypoxic-ischaemic encephalopathy (HIE) in a full-term infant is a clinically defined syndrome of the disturbed neurologic function in the earliest days after birth in infancy, manifested by difficulty with initiating and maintaining respiration, the depression of the muscle tone and reflexes, the subnormal level of consciousness and often seizures (Nelson & Leviton, 1991). HIE is the term used to describe the resultant condition due to a deficit in the oxygen supply to the brain. The neonatal brain can have a lack of oxygen through two major pathogenetic mechanisms, hypoxemia, which is a diminished amount of oxygen in the blood supply, and ischemia, which is a diminished amount of blood perfusing the brain. During the perinatal period hypoxemia or ischemia or both occur as a result of asphyxia, an impairement in the exchange of respiratory gases, oxygen and carbon dioxide. The duration and severity of HIE depend of the severity of asphyxia. Neonatal asphyxial encephalopathy occurs in 1–2 per 1000 births in the high income countries (Marlow & Budge, 2005; Pierrat et al., 2005; Barkovich, 2005), in low-income countries, the incidence is much higher (Ellis et al., 2000; Black et al., 2010).