Neuropathology Of Head Trauma. Mary E. Case, M.D. Professor of Pathology St. Louis University Health Sciences Center

Transcription

1 Neuropathology Of Head Trauma Mary E. Case, M.D. Professor of Pathology St. Louis University Health Sciences Center

2 Nothing to disclose Disclosure

3 Introduction 500,000 cases/year of serious head injury in US 5 to 10% of these are fatal 2/3 of fatal cases are DOA Head injury rate 22-32/100,000 50% traffic, 20-40% GSWs, 10% falls, 5-10% assaults

4 Blunt Trauma Abrasion scraping away of the skin surface, may have patterns Contusion bruise, tearing of vessels beneath skin surface, patterns Laceration tearing open of skin and tissue, tissue bridges, patterns

5 Dicing Abrasion

6 Abrasions

7 Scalp

8 Scalp 2

9 Scalp 3

10 External Clues To Basilar Skull Fracture Ecchymoses Periorbital hematomas Battle sign Blood, brain from ear or nose Wide nasal bridge

11 Periorbital hematomas GSW ecchymoses

12 Orbital Plate Fractures fractures

13 Battle Sign

14 Scalp Lacerations

15 Gunshot Wounds Of Face Certain areas - nose, eyelids, lips, ears Entrance may look very different or unusual May lack typical appearance of abrasion rim, defect May look like tear or exit

16 GSWs GSWs

17 Sharp Wounds Of Face Do not look different from wounds elsewhere on body Not common wounds Most are through orbit, roof of mouth

18 Scalp May not see external evidence of contusion Wounds are best seen from undersurface Injuries can be easily described, measured May take sections for microscopic exam

19 Scalp subgaleal hemorrhage

20 Skull Examine calvarium - peel off periosteum - remove temporalis muscles Describe fractures Remove clavarium - look for epi- or subdural blood Look at fit of brain Remove brain - strip dura

21 Skull 2

22 Skull Fractures Linear Depressed Comminuted Diastatic Compound

23 Linear Fracture Linear fx simple fx line, crack, broad based forces

24 Ring Fracture Ring or circle fx around foramen magnum, forceful hyperextension of head on neck

25 Contrecoup Fracture Fracture of orbital plates from blow to back of head

26 Comminuted Fracture Bone broken into fragments, force over broad area

27 Depressed Fracture Bone pressed inward, small striking surface

28 Depressed Fracture 2 2 areas of depressed fractures

29 Hinge Fracture Hinge fracture across middle cranial fossae through petrous ridges of temporal bones

30 Diastatic Fracture Diastatic fracture enters or opens suture, significant force

31 Mechanisms of Traumatic Brain Injury Static loading force applied slowly > 200 msec crushing head injury Dynamic loading force applied rapidly - < 200 msec produced by direct impact to head (impact) or by causing the head to move by action to the body which causes the head to move (impulse)

32 Mechanisms Static loading rare cause of head injury Dynamic loading accounts for great majority of head injuries Impulsive loading of the head will result in inertial movement of the brain within the cranial cavity» Translational produces focal effects» Rotatory produces both diffuse and focal lesions

33 Inertial Loading Inertial loading creates differential movement of the brain and skull because of differences in rigidity of the two Dura is attached to the skull and moves separately than brain/arachnoid may tear bridging veins (SDH) and axons (tdai)

34 Impact Loading Impact loading - several effects Contact injury»scalp laceration»skull fracture»creates pressure waves into cranial cavity to cause brain contusions»inertial brain movement

35 Blunt Head Trauma Head injury may be focal or diffuse or a combination Focal - direct impact to head and can be seen with naked eye» Scalp laceration/contusion, skull fracture, EDH, focal SDH, brain contusions Diffuse from inertial loading» Interhemispheric SDH, tdai

36 Classification Of Brain Damage From Trauma I. Immediate impact injury A. Contusions and lacerations B. Diffuse axonal injury C. Penetrating injuries II. Primary complications A. Intracranial hemorrhages B. Brain swelling III. Secondary complications - ICP, hypoxia

37 Immediate Impact Injury Contusion bruise, usually on crest of gyrus, clusters of small hemorrhages, wedge shaped with apex toward subcortical white Overlying subarachnoid hemorrhage Not static, increases over time Marked in alcoholics, hypertensives

38 Coup Contusions Contusion beneath point of impact Impact site can be seen on scalp Less severe than contrecoup Massive impact may cause contrecoup pattern

39 Coup Contusion

40 Coup Contusion Contusion beneath point of impact On cerebral convexity

41 Contrecoup Contusion Angular acceleration with moving head impacting a surface on impact rotational movement of brain Rotational movement of brain over sphenoid bone and petrous ridges Contrecoup pattern of contusion over frontotemporal areas

42 Contrecoup Contusion Contusions opposite point of impact Over orbital surfaces, frontal poles, temporal poles Impact to back or side but sometimes front

43 Contrecoup Contusion 2 Rotational shear force theory brain moves within cranial cavity in predictable ways Translational moves in straight line Rotational turns on axis, very damaging due to ridges of cranial fossae, sphenoid bones and petrous ridges

44 Contrecoup Contusions

45 Contrecoup Contusions Orbital surfaces, frontal poles, temporal lobes

46 Contrecoup Contusions Fell down stairs

47 Contrecoup Contusions

48 Contrecoup Contusions Clusters of vertical and streak hemorrhages in cortical ribbon Subarachnoid hemorrhage over surface

49 Contrecoup Contusion old contusions

50 Other Impact Injuries CRUSHED HEAD INJURYskull is fragmented and crushed by weight of object No coup or contrecoup contusions Fracture contusions and lacerations - maceration of brain

51 rowbar Crushed Head 2

52 crowbar Crushed Head 3

53 Crushed Head 4

54 Other Impact Injuries 2 FALL FROM HEIGHT No angular acceleration of head - brain and skull fall at same rate No coup or contrecoup contusions Fractures contusions and lacerations

55 Fall From Great Height

56 Young Children Special developmental and anatomical differences Large heavy head Soft brain - unmyelinated, much water Thin, pliable skull with flat skull base Weak neck support

57 Young Children 2 Trivial falls - translational movement Either impact or shaking of significant degree results in rotational brain injury SAH, SDH, retinal hemorrhages, DAI In infants under 5 months may see contusion tears

58 Diffuse Axonal Injury Many other names in past diffuse white matter damage Acceleration deceleration of head - inertial movement of brain due to greater rigidity of skull - greater movement at periphery of brain resulting in shearing injury

59 Diffuse Axonal Injury 2 Pathology streaks or punctate hemorrhages subcortical white, corpus callosum, deep grey, periventricular white SAH, SDH Micro axonal swelling or varicosities Old loss of white, big ventricles

60 Diffuse Axonal Injury 3 Clinical picture Most often MVA, but also some falls, assaults, AHT Moderate to severe degrees produce immediate onset of unconsciousness Survivors of moderate to severe degrees - usually in vegetative state

61 DAI 4 MVA - dead at scene

62 DAI 5 MVA

63 DAI 6 MVA dead at scene

64 DAI 7 Streak and punctate hemorrhages

65 DAI 8 3days post MVA

66 9 days post MVA DAI 9

67 DAI 10 3 days old axonal bulbs BAPP

68 7 years post MVA DAI 11