An intracranial hemorrhage originating in the periventricular germinal matrix that extends into the fluid-filled ventricles. Most common in preterm and low-birthweight infants, especially those with respiratory distress syndrome, but is relatively uncommon in fullterm infants. Infants with gestational ages of less than 30 weeks are at most risk for IVH. It is thought to arise from alterations in the perfusion of fragile cellular structures that are typical of the growing brain, making the cerebral cortex especially vulnerable to hypoxic-ischmic encephalopathy. The reduction in blood flow results in cell death and subsequent collapse of blood vessel walls, leading to bleeding. IVH is not evident at birth, but presents itself usually within the first 72 hours thereafter. The hemorrhage is graded from the least to most serious as follows:
Grade I: bleeding occurs in the germinal matrix, with few long-term complications
Grade II: bleeding also occurs inside the ventricles
Grade III: ventricles enlarged by blood
Grade IV: bleeding into tissues around the ventricles (this and Grade IV can result in cerebral palsy)
After Grades III and iV, blood clots can form that can block the flow of cerebrospinal fluid, leading to increased fluid in the brain and thus hydrocephalus.
See Cerebral cortex (or pallium), Cerebral palsy, Hypoxic-ischemia encephalopathy, Periventricular hemorrhagic infarction (PVI), Periventricular leukomalcia (PVL), Preterm infant, Respiratory distress syndrome, Sub-ependymal periventricular germinal matrix, Ventricles