Fig. 23.13B ), producing a hematoma that compresses the brain surface. Clinically, patients can be lucid for several hours after the traumatic event before neurologic signs appear. An epidural hematoma may expand rapidly and constitutes a neurosurgical emergency necessitating prompt drainage and repair to prevent death.
Rapid movement of the brain during trauma can tear the bridging veins that extend from the cerebral hemispheres http://ebooksmedicine.net
Table 23.1 Patterns of Vascular Injury in the Central Nervous System
SubduralspaceTraumaLeveloftraumamaybemild;slowlyevolvingneurologicsymptoms,oftenwithadelayfromthetimeofinjury
Dura (peeled off skull) Dura (still attached to skull) Arterial blood Venous blood Skull fracture B A C
Fig. 23.13 Traumaticintracranialhemorrhages.(A)Epiduralhematoma(left) inwhichruptureofameningealartery,usuallyassociatedwithaskullfracture,hasledtoaccumulationofarterialbloodbetweentheduraandtheskull.Inasubduralhematoma(right), damagetobridgingveinsbetweenthebrainandthesuperiorsagittalsinushasledtotheaccumulationofbloodbetweenthethetwolayersofdura.(B)Epiduralhematomacoveringaportionofthedura.
(C)Largeorganizingsubduralhematomaattachedtothedura.(B, Courtesy of the late Dr. Raymond D. Adams, Massachusetts General Hospital, Boston, Massachusetts.) http://ebooksmedicine.net through the subarachnoid and subdural space to the dural sinuses. Their disruption produces bleeding into the subdural space. Because the inner cell layer of the dura is quite thin and in very close proximity to the arachnoid layer, the blood appears to be between the dura and arachnoid, but in reality it is between the two layers of the dura. In patients with brain atrophy, the bridging veins are stretched out and the brain has additional space within which to move, accounting for the higher rate of subdural hematomas in older adults. Infants also are susceptible to subdural hematomas because their bridging veins are thin walled.
Subdural hematomas typically become manifest within the first 48 hours after injury. They are most common over the lateral aspects of the cerebral hemispheres and may be bilateral. Neurologic signs are attributable to the pressure exerted on the adjacent brain. Symptoms are most often nonlocalizing, taking the form of headache, confusion, and slowly progressive neurologic deterioration.
MORPHOLOGYAcutesubduralhematomaappearsasacollectionoffreshlyclottedbloodapposedtothecontourofthebrainsurface,withoutextensionintothedepthsofsulci(see
Fig.23.13C ).Theunderlyingbrainisflattened,andthesubarachnoidspaceisoftenclear.Subduralhematomasorganizebylysisoftheclot(about1week),growthofgranulationtissuefromtheduralsurfaceintothehematoma(2weeks),andfibrosis(1–3months).Subduralhematomascommonlyrebleed,presumablyfromthethin-walledvesselsofthegranulationtissue,leadingtomicroscopicfindingsconsistentwithhemorrhagesofvaryingages.Symptomaticsubduralhematomasaretreatedbysurgicalremovalofthebloodandassociatedreactivetissue.
CENTRALNERVOUSSYSTEMTRAUMAthrough the subarachnoid and subdural space to the dural sinuses. Their disruption produces bleeding into the subthrough the subarachnoid and subdural space to the dural sinuses. Their disruption produces bleeding into the sub
Physicalinjurytothebraincanoccurwhentheinsideoftheskullcomesintoforcefulcontactwiththebrain.