Intracerebral hemorrhage and head trauma: common effects and common mechanisms of injury

Abstract

Nontraumatic intracerebral hemorrhage (ICH) remains a devastating condition with 30-day mortality rates of 35% to 52%. Until the pathophysiology of this condition is better understood, it will not be possible to develop effective therapies. Studies of cerebral blood flow and metabolism in patients with acute ICH show similar abnormalities to those that occur in patients with traumatic brain injury, thus raising the question of whether there are common mechanisms of injury shared by the 2 conditions. In both ICH and traumatic brain injury, there is an early reduction in the cerebral metabolic rate of oxygen without ischemia, mitochondrial dysfunction, and transient focal increases in regional glucose metabolism that occur after a few days. ICH and traumatic brain injury share barotrauma from pressure waves that propagate through the intracranial contents as a common mechanism of brain injury. Recent data demonstrating contralateral hemispheric damage in patients with acute ICH provide further support for this theory of common injury mechanisms.

Figure 1

Positron emission tomography studies of cerebral oxygen metabolism in patients with intracerebral hemorrhage (ICH) and traumatic brain injury (TBI). Data from references 2 and . CBF - cerebral blood flow (mL 100 g⁻¹ min⁻¹), CMRO2 –cerebral metabolic rate of oxygen (mL 100 g⁻¹ min⁻¹)

Figure 2

Mitochondrial State 3 Respiratory Rate in Human Brain Tissue after intracerebral hemorrhage (ICH) and traumatic brain injury (TBI). Data from references 8 and

Figure 3

Diagrammatic representation of barotrauma as a mechanism of diffuse brain injury in traumatic brain injury (TBI) and intracerebral hemorrhage (ICH).

Figure 4

Change in hemispheric volume following acute intracerebral hemorrhage (ICH). Data from reference 21

Figure 5

Permeability-Surface Area (P-S) product reflecting Blood:Brain Barrier Permeability to X-ray contrast following acute intracerebral hemorrhage (ICH). Contra Infarct – Control data from the hemispheres contralateral to cerebral infarction. Data from reference 22

Figure 6

Fractional anisotropy (FA) in the contralateral peri-ventricular white matter in a 76 year old man 7 days after acute intracerebreal hemorrhage compared with age-matched normal control subjects.