Pseudo-controversies in Abusive Head Trauma

Document Sample
Pseudo-controversies in Abusive Head Trauma Powered By Docstoc
					Pseudo-controversies in
 Abusive Head Trauma
       John E. Wright, MD, FAAP
           Medical Director,
  Broward County Child Protection team
               Epidemiology
   The incidence of inflicted head trauma
    during the first or second years of life has
    been estimated in various studies to range
    from 16.1 to 33.8 cases/100,000 infants/y
   Abusive head trauma appears to be the
    leading cause of infant homicide in the
    United States.
         Epidemiology, (cont.)
   The incidence of traumatic brain injury
    and/or fracture due to abuse was
    21.9/100,000 in children less than 36m
    and 50.0/100,000 in children less than
    12m.
          Broward County, FL
   109,060 total population under age 4
   452,754 total population under 19.
   State Child Protection System, Local
    system administered by Sheriff‟s Office
    with expert consultation by CPT for
    mandatory referrals.
               Personal intro
   Practicing pediatrics in Fort Lauderdale
    since 1987.
   First saw child abuse in training at U of M
   Serves as medical director of Broward CPT
    from 1989 to 1991 and 1999 to present
   Described “abusive head crushing”
    Commonality Factors In Safety and Risk Assessments for
                                    Reports with Findings
                                           AGE <= 4
                                           100
                                            90
           Unrelated visitor / or
                                            80
           biologically unrelated           70               Increased Vulnerability
           person in household              60
                                            50
                                            40
                                            30
                                             31
                                            20
                                            25
                                             15
                                            10
      Pattern of Incidents           49      0        48            Dom. Violence Hist.
                                             13
                                                   50
                                      73

                    Prior Reports                            Criminal History


                                     Mental Health / Drugs

                                                                                  Unrelated
 Safety Factors                                                          Pattern visitor / or
                         Increased Dom.                 Mental Prior
in Verified and                                Criminal                    of    biologically
                AGE <= 4 Vulnerabilit Violence          Health / Report
   indicated                                   History                  Incident unrelated
                              y         Hist.            Drugs     s
    reports                                                                 s     person in
                                                                                 household
        Economic drivers of junk
              science
   Individual cases are unique, but not
    generally without precedent
   Data collection is time sensitive
   Input from multiple sources some with
    agendae
   System reacts to case:
     Civil system of child protection
     Criminal system of prosecution of perp

    Information is filtered and re-presented in an
      illogical fashion
       Economic drivers of junk
       science in the courtroom
   Systemic response is cumbersom and
    susceptible to sabotage at multiple steps
   Alternative hypothesis are not subjected
    to any testing or reasonable filters of
    medical knowledge. Their intention is to
    raise confusion and doubt.
   Courtroom diagnoses are proffered
   A variety of logical errors are exploited in
    the theatrical conflagration that ensues
   The media loves it: free entertainment.
    Alternative hypothesis themes
        (in no particular order)
   Biomechanical
       Same “expert” will state that there‟s not
        enough force and that the findings could be
        cause by minimum trauma.
   Blame the victim: it‟s not trauma
     Coagulopathy, connective tissue defect,
      temporary brittle baby,
    Blame the environment
     vitamin/nutrient deficiency, environmental
      toxin
    Alternative hypothesis (cont.)
   Any test not ordered in the acute phase.
   CPR/resuscitation efforts
   Seizure
   Infection
   Older injury
   Birth trauma
   Spontaneous x
   Arteriovenous malformation
        Irresponsible expert tricks
   Divide and conquer
       Tease out a few abnormalities and pretend
        that they were causative rather than the
        result of the head injury
   You forgot to check…serum porcelain level
   Find some obscure ill-defined case report
    from the medical literature that was
    probably in itself missed child abuse.
         Dealing with Irresponsible
            Expert Testimony
   Question to the visiting expert: What Information
    regarding this case have you brought with you from
    wherever?
   Examine writings/written opinions/previous testimony.
       John Plunkett, MD             Sudden Death in an Infant Caused by Rupture of a Basilar Artery Aneurysm,
        Am J. Forensic Medicine and Pathology, 20(2):211-214, 1999.

       Cites in abstract that morphologic findings of ruptured aneurysm
        include retinal hemorrhage.
       In case report notes: The eyes were not examined.
Carl Sagan’s Baloney Detection
              Kit
   Ad nominem attack            Statistics of small numbers
   Argument from authority      Inconsistency
   Argument from adverse        Non sequitur
    consequences                 Post hoc, ergo propter hoc
   Appeal to ignorance          Meaningless question
   Special pleading             Excluded middle or false
                                  dicotomy
   Begging the question         Slippery slope
   Observational selection      Confusion of correlation and
   Suppressed evidence           causation
   Weasel words                 Straw man
         7 warning signs of bogus
                 science
   1. discoverer pitches the       5. discoverer says a
    claim directly to the            belief is credible
    media
                                     because it has
    2. discoverer says that a

                                     endured for centuries
    powerful establishment is
    trying to suppress his/her      6. discoverer has
    work.                            worked in isolation.
   3. The scientific effect        7. discoverer must
    involved is always at the        propose new laws of
    very limit of detection
                                     nature to explain an
   4. evidence for a
                                     observation
    discovery is anecdotal
    Mathematician, Mark Kac
“Proof: That which convinces a reasonable
  person.
Rigorous Proof: That which convinces an
  unreasonable person.”


Legal standard of Proof: ?
Consilience: Scientific evidence
         is accretionary
  “Interesting”
  “Suggestive”

  “Persuasive”

  “Compelling”

  “Obvious”
                 “Interesting”

   Catherine Welch : April 10th 1828.

“ I am a surgeon and live at Fulham…the
Eyes were a good deal suffused with
blood…I opened the body after the
inquisition, the internal parts were perfectly
healthy, except the vessels of the brain and
lungs, being overloaded with blood.”
        Interesting/suggestive

“ I asked my husband what he had done
  and he said he had taken the baby by the
  shoulders and must have shaken it too
  much…”

Ethel Muckle, a neighbour said when she
asked Strand what he had done he said
 “… I only shook the baby…”
         “Suggestive/compelling”


 NYT 1937
Joseph MOLINARI
Prosecutor

Boyfriend confesses
he shook to death a
  15
month old baby
because “it bit me”
                       Suggestive
Dr. John Caffey, Multiple Fractures in the long bones of
  infants suffering from chronic subdural hematoma,
  American Journal of Roentgenology, 1946.
      Dr. Caffey described 6 cases of his own and 6 cases that had
       been reported to him by other physicians.
      “In each case the unexplained fresh fracture appeared shortly
       after the patient had arrived home from the hospital. In one
       case the infant was clearly unwanted by both parents and this
       raised the question on intentional ill-treatment.”
              Compelling/persuasive

   Virginia Jaspers
   August 23rd 1956 shook
    11 day old Abbey
    Kasparov to death.
   Killed three children in
    her care in New Haven,
    USA.
   Said that she had to
    shake the children,
    to„bring the bubble up‟.
Guthkelch, Infantile Subdural Haematoma and its
  Relationship to Whiplash Injuries, BMJ 1971


   “One must keep in mind the possibility of
    assault in considering any case of infantile
    subdural haematoma, even when there
    are only trivial bruises or indeed no marks
    of injury at all, and inquire, however
    guardedly or tactfully, whether perhaps
    the baby‟s head could have been shaken.”
    On the Theory and Practice of
    Shaking Infants: AJDC, 1972
   “During the last 25 years substantial
    evidence both manifest and circumstantial,
    has gradually accumulated which suggests
    that the whiplash-shaking and jerking of
    abused infants are common causes of the
    skeletal as well as the cerebrovascular
    lesions; the latter is the most serious
    acute complication and by far the most
    common cause of early death.”
            Abusive Head Injuries
   Subdural hemorrhage
   Retinal hemorrhage
   Brain injury (diffuse axonal injury)
   Secondary effects (include):
       seizures,
       hypoxic-ischemic,
       toxic metabolytes,
       Swelling
       Coagulopathy
       Loss of autoregulation
               Duhaime, et al
   Described 48 cases at CHOP between
    1978 and 1985. Autopsy findings of 13
    fatalities: all fatal cases had signs of blunt
    impact to the head. In half of these
    impact site found only on autopsy.
   All deaths assoc. with uncontrolled
    increased intracranial pressure. Small
    subdural collections.
              Duhaime et al.
   Part 2 of her NEJM article used a model
    with a single velocity transducer and
    measured peak change in velocity in
    shaking vs. impact (g force). Suggesting
    that shaking alone was not sufficient to
    cause brain injury. She cited:
   Thibault and Gennarelli: Biomechanics of
    diffuse brain injuries, Proceedings of the
    Fourth Experimental Safety Vehicle
    Conference. New York: Am Assoc. of
    Automotive Engineers, 1985.
       Cited by Duhaime et al as basis for
        biomechanical thresholds.
       Used adult monkeys (rhesus,
More recent biomed
      studies.
      More recent biomedical
             analyses
Computer model (2 dimentional model of an
 axial skull and brain slice subjected to two
 seconds of four cycles/sec shaking):
 produced brain strains sufficient to
 produce traumatic axonal injury in the
 corpus calosum and cerebral pedicles,
 cingulate gyrus, inferior frontal lobe, and
 inferior occipital lobe and most bridging
 veins developed sufficient skull/brain
 displacement to predict vein rupture.
AHT: Shaking and/or Impact?

   Shaking can cause              Impact can cause
       Retinal hemorrhage             Skull fractures
       Hemorrhage outside of          Subgaleal hemorrhage
        optic nerve sheath             Visible bruises, abrasions,
       Subdural hemorrhage             skin fxs
       DAI                            Epidural hem.
       Cerebral edema                 Focal findings
       death                          Coup/contracoup
                                       Cerebral edema
                                       death
          Shaken Adult Syndrome
   Derrick J. Pounder, MB, MRC Path, American Journal of
    Forensic Medicine and Pathology, 18(4):321-24, 1997.
   30 year old Palestinian collapsed under interrogation by
    Israeli General Security Service, declared brain dead 3
    days later.
       Extensive anterior chest and shoulder bruises, acute subdural
        hemorrhage, DAI, RH. Wt. 44.3kg, Ht151cm
       All 3 pathologists agreed that the death was unnatural and the
        result of brain damage due to rotational acceleration of the head
        without direct impact.
       Shaken Adult Syndrome
   Disclosed in court proceedings that
    interrogation began at 4:45 am and
    continued until 4:10 pm.
   Shaken 12 times, 10x grabbed by clothing
    2x grabbed by shoulders.
   “Collapsed with clouded consciousness,
    mucous fluid came out of his nostrils and
    fluid came bubbling out of his mouth.”
Maya

     61/2 week old
     Last seen frisky and healthy
      the night before
     Couldn‟t lift head, 2 legs rigid,
      3rd leg weak,
     Couldn‟t swallow or move
      tongue
     Had been isolated in a special
      pen with her 3 year old
      mother and another mother
      and cub
Maya, cont.

         MRI scan: Cerebral edema,
          loss of gray/white matter
          differentiation, increased
          signal on T2 weighted
          sequence. No significant
          mass effect. Prognosis good.
         Clinical improvement;
          growling and batting at IV
          tubing by day #5.
    Animal Models: Observations
             of Nature
   Nature films showing young male lions
    shaking lion cubs (mother‟s new
    boyfriend)
   The Functional Anatomy of the
    Woodpecker
   Predator hunting behaviors involving
    shaking of smaller prey; canine, feline.
    IRRESPONSIBLE MEDICAL
          TESTIMONY
   Krous and Chadwick (1997) described
    several features including:
       Physicians without adequate background (e.g.
        training, don‟t do research or see patients
        with regard to issue)
       Contrived or far-fetched theories of causation
       Not reproducible
       Selective use of the literature
    SHAKEN BABY SYNDROME
   Probably the diagnosis that brings out the
    most “junk science” in the court
   Media:
       Newspapers - usually do a pretty good job
       National television networks - awful to
        mediocre to excellent (thanks CNN!)
                         CPR
   Claim: causes rib fractures and retinal
    hemorrhages
   Truth:
       Rib fractures do not occur in infants and
        young children (they bend)
       A few petechiae or spots in very rare cases of
        children with existing bleeding tendencies
        (e.g. sepsis, DIC)
            RESCUE SHAKING
   Claim: Shook to revive. Amateurs,
    panicky.
   Truth:
       Doesn‟t happen in cases where reason for
        revival is known
       Not enough force, unless they are claiming
        abuse
    SUBDURAL HEMORRHAGES
   Claim: caused by trivial trauma or CPR
   Truth:
       Subdurals rarely seen with short falls -
        especially if no fracture
       CPR does not cause subdurals
           SBS IS NOT REAL
   Claim: SBS is not real, it is all impact or
    something else.
                 SBS IS REAL
   Truth:
       Hundreds of articles in medical literature
       2 position papers by AAP
       Statements by National Association of Medical
        Examiners, Canadian Pediatric Society
       Statements by US Advisory Board on Child
        Abuse and Neglect
       NO statement to the contrary by any major
        medical association
                 SBS IS REAL
   Truth:
       ICD - 9 code for “shaken infant syndrome”
       Over 600 participants at four USA SBS
        conferences
       International conferences in Sydney,
        Edinburgh – Montreal in Sept. 2004
               SBS IS REAL
   Starling S, et al. Analysis of perpetrator
    admissions to inflicted traumatic brain
    injury in children. Archives of Pediatrics
    and Adolescent Medicine 158:454-458,
    2004.
                SBS IS REAL
   Retrospective look at 81 cases of admitted brain
    injury to 90 cases of in which no abuse
    admission was made
   68% of the confessed perpetrators said no
    impact – only shaking
   91% of the cases in which timing was described
    – symptoms were immediate. In 9% the timing
    was unclear.
   NONE were normal after the event
               SBS IS REAL
Conclusions:
  1.   Symptoms are immediate
  2.   Most perpetrators admit shaking without
       impact
  3.   Relative lack of skull/scalp findings (vs.
       impact admitted cases) = shaking alone can
       produce the findings of SBS
             CONTRARIANS
   Statement in a highly publicized case –
    “more recently it has been shown that
    short falls can some times cause serious
    or fatal injuries”
   Talk about the “new science”
   YET – no data that really supports this
   Example that some just do not want to
    see child abuse, especially with “nice”
    people
          Dr. Ronald Uzcinski
   SBS not real
   Can‟t generate severe enough forces
   F=ma “It‟s all about physics”

[View shared in part by Vincent DeMaio,
  John Plunkett]
          Dr. Ronald Uzcinski
   In a recent Naples FL case he said that
    burping an infant can cause bleeding in
    the head
   Also the infant straining with a bowel
    movement
              LANTZ ET AL. 2004
   Reported that a 40 pound TV falling on a
    month old caused perimacular folds
   Prior to this, such folds seen only with
    shaken baby syndrome
Lantz PE, Sinal SH, Stanton CA, Weaver RG. Perimacular retinal folds from
   childhood head trauma. BMJ (2004) 328:754-756.
          LANTZ ET AL. 2004
   In an editorial in the BMJ, Geddes and
    Plunkett extrapolated this to retinal
    hemorrhages and said whole concept of
    SBS is untrue
   Comment: Based on one controversial
    case of a TV crush injury?
                  GEDDES
   Has published several articles showing
    deep brain damage with shaking
   Thinks secondary to hypoxia
   Has speculated that mild shaking might
    cause more SBS than we think
   Has claimed microscopic intradural
    hemorrhages present in many situations
    (most think of this as an artifact – not the
    larger SDH of SBS)
                 GEDDES
   Why not same findings in drownings if
    hypoxia is the mechanism? What about
    retinal hemorrhages?
   While her speculation is seemingly
    opposite of others saying shaking not
    enough to cause serious brain damage,
    they seem to have no problem disputing
    mainstream SBS wisdom
                  GEDDES
   Retracted her “hypothesis” in British court
   But others still use it
           Dr. Tom Nakagowa
   If f = ma, and a = gravity (a constant)
   Then f ~ m
   Then bigger m leads to bigger f
   The bigger you are, the harder you fall
   When adults fall off couches, they hit the
    floor much harder.
          Dr. Tom Nakagowa

   Why do adults commit suicide by jumping
    off of bridges/buildings – when the couch
    or bed would do?
        BIOMECHANICS OF SHAKING


                                    Single shake
                                    models



Force




         Human range




                                                   Geddes notion

                   Time (# of shakes)
    KEY DAMAGE ISSUES
•   It is the brain damage that causes serious
    injury or death. Not the secondary injuries
    of bleeding in the retina or intracranial
    spaces
•   Not a mass effect issue
•   SBS brain injury is not superficial, but
    involves deeper structures. (Pattern of
    atrophy in survivors is different than seen
    with isolated contact injuries.)
KEY DAMAGE ISSUES
   Arguments against mainstream
    opinion tend to focus on the
    secondary injuries (especially
    SDH) and lightly dismiss the
    brain injury and retinal
    hemorrhages
        SHORT FALLS CAN KILL
   Van EE and others (engineers, physicists)
    do models and claim short falls can kill
   Truth:
       They do not apparently know or care about
        real world data
           ACCIDENTAL FALLS
   Claim: Short falls cause serious or fatal
    injuries. SBS injuries look like short fall
    injuries.
   Truth:
       Frequently the excuse
       Extensive review of fall studies does not
        support serious injuries (e.g. Helfer et al,
        1977; Chadwick et al, 1991; see Alexander,
        Levitt, and Smith‟s upcoming chapter).
ACCIDENTAL FALLS (CONT)
   Experience shows that children are constantly
    having short falls without serious injury
   Like a single shake
   Retinal hemorrhages almost never seen and
    should not be extensive
   Strong evidence of impact
ACCIDENTAL FALLS (CONT)
   About 1% of children falling 3 feet to a hard
    surface will have a short fracture to the side
    of the head
   They do not have significant brain injury
       ACCIDENTAL FALLS
   “Killer beds”, “killer couches”
   Patterns of injury with accidental impacts do
    not look like SBS
        DUHAIME ET AL, 1987
   Study found 13 dead SBS victims - all had
    signs of head impact
   Models and testing suggested that shaking
    alone not sufficient to cause serious injury
    or death
   Forces are immense
   SBS cases should be called shaken-impact
    syndrome
     DUHAIME ET AL, (CONT.)
   At least a dozen data-based studies since
    then all have found shaking is sufficient.
    No other study shows impact is necessary.
   Thus there is no controversy
   It does not matter in court anyway - it is
    all violent abusive head trauma
     DUHAIME ET AL, (CONT.)
   Note: Duhaime says the forces are worse
    than the most violent shaking
   Those who think shaking is sufficient also
    believe in extreme forces being necessary
   Thus the perpetrator was violently abusive

Duhaime AC, Gennarelli TA, Thibault LE, Bruce BA, Margulies SS, Wiser
  R. The shaken baby syndrome. A clinical, pathological,
  biomechanical study. J Neurosurg (1987) 66:309-15.
               RE-BLEEDS
   Claim: These cases have an old injury
    (timing is too uncertain to establish
    perpetrator) and a re-bleed of the
    subdural causes new subdurals, retinal
    hemorrhages, and can be fatal

   [Dr. Jan Leetsma often claims this,
    Plunkett and Uzcinski sometimes also]
                  RE-BLEEDS
   Truth:
       Any scab will ooze blood with small trauma
        prior to complete healing
       After several weeks of healing, a subdural
        hematoma will form delicate new blood
        vessels
       Minor head trauma can cause re-bleed
       No associated retinal hemorrhages or cerebral
        edema
              RE-BLEEDS
   Slow process
   Possibly expanding head size
   Increasing lethargy
   Diminished appetite
         RE-BLEEDS VS. SBS
   Re-bleeds should not be sudden or fatal
   SBS is primarily a brain injury, re-bleeds
    are not
   The presence of old injuries, new
    intracranial bleeding, retinal
    hemorrhages,and clinical signs of brain
    injury = old and new SBS
   Second shaking needs to be violent as
    well
               VACINNATIONS
   Claim: DPT shot causes SBS
   [Vera Schribner – paleoarcheologist from
    Australia is active on the internet]
   Truth: No
       No mechanism for this
       No evidence for this
          METABOLIC DISEASE
   Claim: metabolic diseases mimic SBS
       e.g. Glutaric aciduria
       unspecified others
         METABOLIC DISEASES
   Truth:
       Name the metabolic condition
       Bleeding diseases usually cause fatty livers
       SBS is not a bleeding disease
       Metabolic diseases do not suddenly appear
        and disappear
    CHILD IS TOO OLD FOR SBS
   Claim: SBS happens only to children
    under 1 or 2 years of age
   Truth:
       Most under 1 year, some between 1-2 years,
        less 2 year olds, rare 3 or 4 year olds
       Physiologically can happen at any age
       SIZE is the issue
        CHILDREN ARE UNIQUELY
             VULNERABLE
   Claim: children are easily damaged
    because of weak neck muscles, large
    heads, etc.
   Truth:
       No literature to support assertion of “weak”
        neck muscles
       No data to show that child‟s physiology puts
        them at extra risk
        CHILDREN ARE UNIQUELY
             VULNERABLE
       Brain fits inside skull - no room to bang
        around in it
       Adults could not resist a 2000 pound gorilla,
        and their physiology would not help


   Note: this claim blames the victim!
        RETINAL HEMORRHAGES
          ALWAYS MEAN SBS
   Claim: Child “savers” always say retinal
    hemorrhages = SBS
   Truth:
       Not true (MVC may cause retinal
        hemorrhages)
       It is the type and pattern of retinal
        hemorrhages (extensive, to the periphery,
        different layers) that is even stronger
        evidence
        RETINAL HEMORRHAGES
          ALWAYS MEAN SBS
   BUT:
       We too often list differential diagnoses that
        make no sense for children in general, or for
        the clinical circumstances of the case
       Such mindless differentials can cause court
        confusion
              LUCID INTERVAL
   Claim: Can not time when the injury
    occurred clinically. May act fairly normal
    for awhile before sudden collapse.
   Truth:
       NO
       Not the finding in known accidental injuries
       Assumes bleeding, not brain injury is the
        issue.
MODELS
CONSUMER PRODUCT SAFETY COMMISSION


   When studying playground falls
   They did calculations
   Decided that falls as little as 2 inches onto
    a hard surface might cause serious or fatal
    injuries!
                            Quoted by Iowa State University
                 MODELS
   Models attempt to describe reality – but
    they are NOT reality
   They are always an approximation
   They may be helpful
   They are often too simple
   They may be wrong or insufficient
MODELS THAT ARE TOO SIMPLE
F = ma. SBS is like a fall
 Clinical injury pattern is not that of a fall

 Are the histories by perpetrators of
  shaking really wrong? (Maybe those
  “killer” couches really did it.)
MODELS THAT ARE TOO SIMPLE
The amount of force reduces to a
  single unit (often a “g” force)
 42?

 Which of 100 billion neurons is being
  described?
 Which of 1000‟s of forces is being
  selected?
 Complex motions: how much force does it
  take to walk?
MODELS THAT ARE TOO SIMPLE
F = ma. SBS is like a fall
 As Chadwick (1991) showed, third story
  falls have a <1% death rate (without RH),
  yet SBS has a 25% death rate (with RHs
  in about 90% of cases). SBS is a different
  entity.
 The simple fall notion ignores individual
  brain cells/layers. Usually this “model”
  focuses on SDH only.
MODELS THAT ARE TOO SIMPLE
F = ma. SBS is like a fall
 Corresponds to a single shake

 No one really thinks that a single shake causes
  SBS – the argument sets up a strawman
 Example: Duhaime et al (1987) used a doll
  model and showed that stopping suddenly
  (impact) creates more G forces than stopping
  slower (end of shake in air). Obvious finding.
  Does not speak to repetitive injuries at all (for
  which no animal data is shown).
MODELS THAT ARE TOO SIMPLE
F = ma. SBS is like a fall
 Sets up idea that shaking is not enough –
  the perpetrator must have been
  exceptionally violent!
 (Not what is argued by defense witnesses
  who want it both ways – violent shaking is
  not enough force, but mild impacts can
  cause everything.)
MODELS THAT ARE TOO SIMPLE
APNEA MODEL
 Key brain cells are damaged and apnea
  results
 May need only minimal forces – Geddes
  argument in several of her papers
 This is stated as a conclusion without
  data.
MODELS THAT ARE TOO SIMPLE
APNEA MODEL
 Apnea is a common clinical entity in the NICU
  – not common outside of it
 The pattern of brain injury and bleeding in SBS
  does not correspond to injuries seen by other
  apnea causes
 However: hypoxic/ischemic injuries are part of
  the evolution of most SBS injuries to the brain
  (but a small number of children die very
  quickly before much bleeding or cerebral
  edema)
MODELS THAT ARE TOO SIMPLE
APNEA MODEL
 Missing in such histories: why the apnea
  in the first place?
 AAP is against apnea monitors – they
  don‟t really work
    A MORE REALISTIC MODEL
   Motions
       Arc in the AP direction (raises angular
        acceleration to the 4th power – not terminal
        impact)
       Head pivots on the neck
       Neck can bend to the left and/or right side
       All this happens on a body that is moving
        back and forth
       Motions are repetitive
    A MORE REALISTIC MODEL
   Result: a repetitive, 3-dimensional series of
    complex motions with features of reinforcement,
    resonance, and consecutive damage
   The complex of motions explains why one side
    of the brain (or one eye) is exposed to
    somewhat different forces and asymmetry may
    be seen
   Explains direct brain injury, intracranial bleeding,
    and retinal hemorrhages (presumably vitreous
    traction/mechanical rotational flow stresses)
        DIFFICULT DIAGNOSIS?
   Claim: SBS is a difficult diagnosis
   Truth:
       Often made by local physicians without undue
        difficulty
       Paramedics and residents often make the
        diagnosis
       No medical condition truly mimics SBS
             NEW DIAGNOSIS?
   Claim: SBS is a new diagnosis to medicine
   Truth:
       Tardieu (1860) described cases
       Caffey (1946) clearly described cases
       Guthkelch (1971) first linked shaking to the
        injuries
          NEW DIAGNOSIS?
   SBS has been recognized longer than:
      AIDS
      Lyme disease

      Gulf War syndrome

      Ebola virus

      Infectious cause for ulcers

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:13
posted:12/1/2011
language:English
pages:99