Multifocal haemorrhagic brain damage following hypoxia and blood pressure lability: case report and rat model

Abstract

We conclude that transient hypoxia, in a dose-dependent manner, can weaken the vasculature and predispose to brain haemorrhage in the situation of labile blood pressure. Persistent hypoxia is likely to be important in the genesis of permanent severe brain damage.

Third trimester-equivalent ethanol exposure causes micro-hemorrhages in the rat brain

“…Therefore, the micro-hemorrhages are likely the result of direct actions of ethanol on the developing cerebral microvasculature. As discussed above, ethanol-induced cerebral vasoconstriction is one of the factors that could be involved in the mechanism of action of ethanol and this may explain the similarities between our results and those of Pahlavan et al, (2012).…”

“…This finding suggests that ethanol exposure during the rat equivalent to the second trimester of human pregnancy can also cause micro-hemorrhages in the fetal brain, although these are predominantly found at a different location than those caused by third trimester ethanol exposure. (Pahlavan et al, 2012) demonstrated that exposure of newborn rats to hypoxia (50-60% reduction in O 2 tension with respect to ambient air), administered in conjunction with the vasoconstrictor agent, phenylephrine, induced petechial hemorrhages in several brain regions, some of which overlapped with those that showed micro-hemorrhages in our ethanol vapor exposure model (i.e., cerebral cortex, hypothalamus, midbrain, olfactory tubercle, striatum). The similarity between the patterns of micro-hemorrhages found in the brains of neonates exposed to hypoxia/vasoconstriction and ethanol is unlikely to be a consequence of the presence of low O 2 levels in the ethanol chambers, as these were minimally reduced to 92% of control in the high dose experiments.…”

“…During the first week of life in rats (equivalent to the third trimester of human gestation; Clancy et al, 2007), studies from a number of laboratories have demonstrated that developing cerebral micro-vessels are particularly susceptible to rupture in response to insults, such as exposure to ionizing radiation and increases in vascular tone (Landolt and Arn, 1979, Pavlik and Mares, 1992, Pahlavan et al, 2012). Based on these studies and the fact that ethanol can induce vasoconstriction (Altura et al, 1983, Liu et al, 2004), we hypothesized that ethanol exposure during this period of development could induce rupture of brain micro-vessels.…”