2Cases Report And Literature Review Of Diaschisis With Thalamic Hemorrhage

Diaschisis(DC) is defined as brain dysfunction in a region of the braindistal to a site of injury that is anatomical connected to the damaged area.There are many symptoms, clinical signs of nervous diseases not caused byfocal lesion on CT or MRI. DC can explain the phenomenon.In2011wetreated2patients caused by diaschisis of thalamus hemorrhage.Now we willreport the cases and review the literature of diaschisis. Focal cerebralischemic or hemorrhagic stroke can cause changes of cerebral blood flow,metabolic in distant areas. Diaschisis of stroke often occurrs in the ipsilateralhemisphere, contralateral hemisphere especially mirror site, and crossedcerebellar(CCD). Possible mechanisms include the decrease of cerebral bloodflow，metabolic defects in distal areas of the lesion and nerve functiondisconnection theory,1: ipsilateral hemisphere disconnection: after focalinfarction or hemorrhage lesions, low perfusion extends to adjacent cortex.2.contralateral hemisphere disconnection (especially the mirror site), caused bythe corpus callosum fiber.3. crossed cerebellar disconnection (CCD), causedby interruption of cortico pontile cerebellar pathway (CPC). Also includesapoptosis or late-onset neurodegenerative mechanisms. Pathophysiologicalchanges include1.electrical activity inhibited as waves of spreadingdepression (SD). suppression of electrical activity and a large direct currentshift associated with the redistribution of ions between the intracellular andextracellular space. Even in non-ischemic regions, these waves inducesignificant metabolic stress, with an initial increase in brain metabolismfollowed by profound hypometabolism and transient changes in theexpression of a number of neurotrophic and inflammatory cytokines andmolecular signalling cascades.2.Neurotoxic substances slow removal.3.Interruption of neurotrophic substance transportation.The majority of scholars believe that diaschisis is reversible, but continue to exist whenreversible neural dysfunction turning to nerve degeneration. CCD is notcorrelated with clinical outcome, stroke scale and severity ofdamage lesions.There is no unified view about the relationship between theseverity of the lesions, size, duration of illness, the severity of neural functiondefect and CCD. The clinical symptoms, signs and cerebral perfusion andother auxiliary examination should be combined to disease diagnosis. Theexploration of secondary damage to distant area and early treatment toalleviate the secondary damage is important, which can improve the qualityof patients’lives.