HEAD INJURY

Classification:

Localized:

• scalp  injury:  can create large  hematoma. Inspect  the  wound  for  bony  fragments,  but  do  not remove  them. Galea is  sutured  first.
   
• skull  injury :  step -off  on  digital  exam. Special  consideration  is  basal  skull  fx  diagnosed  by : a) otorrhea b) rhinorrhea  c)  Battle  sign  d) hemotimpanum  e)  raccoon  eyes . In  case  of  a)  and  b) " Ring   sign" is  done  on  filter  paper  or  sheet and  double  ring  is  created  with  blood  in  the  middle.  Also  in  case  of  b)  dextrostix  is  useful (CSF  contains  glucose  while  nasal  mucosa  does  not). The  CSF  leak  is  managed  conservatively.  Use  of  antbx  is  in question.  Pay attention  not  to  miss  middle  meningeal   artery  laceration. It  is  of  note  that  skull  x- rays  are  not  rewarding.
  In case of  linear fx, if penetration is suspected get CT.
  If depressed fx is suspected ® CT.
   
• contusion: hemorrhagic  areas with  subarachenoid  hemorrhages  present   in  frontal  and  temporal lobe.  Pt  has longer period  of   coma  and  mental  status changes. Some times focal neuro findings are present.
  Treatment: -head  elevation and  admission   for  repeat  CT  in  AM .
   
• intracranial  hemorrhage -  this is further classified into:
     
1. Epidural -  2ry  to  mid  meningeal  artery injury.  LOC  with  short  lucid  interval.On  CT   lenticular  shaped  hyperdensity. In  80%  skull  fx  is  evident.
    
2. Subdural -    2ry  to  acceleration - deceleration  with   tear  of  bridging  veins.  Can  be  acute i.e. <24  hr.,  subacute i.e. 24hr. - 2wks , or  chronic >  than  2  wks.   It is  more   common  than  epidural .  Skull   fx   not    always  present  and   under-   lying   brain  injury   is  more   severe . On CT, crescent shape along the inner table of the skull.
    
3. Subarachnoid - CSF  is  bloody .  Meningeal  irritation  is  present .  Pt  c/o headache and   photofobia . This is the most common bleed s/p head trauma.

Diffuse:

These  injuries  are  secondary   to  acceleration - deceleration   with  consequent   physiological rather  than  anatomical  changes. Following are the causes of the diffuse head injuries:

1. concussion:  brief  LOC . Pt  may  c/o  n/v ,  dizziness, but  neuro  exam  is  essentially   wnl . If mental  status  clears  completely,  pt  can  be  dc  home. If pt while in ER or after DC home comes back with worsening HA or worsening GCS, repeat CT.
    
2. diffuse  axonal  injury  (DAI ) :    severe  injury  characterized  by  prolonged   coma  for  days or  wk. Increase  in  ICP  is 2ry  to  edema. DAI  is  2ry  to  diffuse  microscopic  damage  throughout the brain . Autonomic  dysfunction  occurs   with  fever,  increase  in  BP ,  sweating.

1. HA, Nausea, Vomiting, LOC, GCS are only few of the symptoms.
    
2. Above S&S can be attributed to ICP (Increase Intracranial Pressure) and Herniation  Syndrome.  Increase  ICP  is   defined   as  CSF  pressure  > than  15mmHg.  ICP  can   be  modified  by  changing   mean  systemic  arterial  pressure (SAP)  and by  changing  PCO2 (CO2 has cerebral  vasodilatory effects) without  affecting  the Cerebral  Perfusion  Pressure (CPP).  It  is  expressed   as CPP=(SAP - ICP). If is  intact,  CPP can  range between  45  and  165mmHg .  Once out   of   this  range both  perfusion  and   metabolism  of  the  brain  are  adversely affected. Four  common  herniations are:
    
1. uncal  herniation: as  uncus  is  medially  forced, ipsilateral CN III is  compressed   producing   pupilary  dilation , ptosis ,  and  as  the  process  progresses  pyramidal  tract   is  involved, with  consequent   controlateral  hemiplegia . Further  progression  will  compress  brain stem  leading  to respiratory  and  cardiac  arrest .
    
2. central  herniation : occasionally   hematoma  of  vertex  or  frontal   lobe  can  force  both  hemispheres downward  through  the  tentorium  . S+S  are  similar  to  uncal  herniation   but  motor  weakness is  bilateral
    
3. cingulate  herniation:  compresses   the  ventricles
    
4. posterior  fossa  herniation : if  herniates  via  foramen  magnum,  brainstem dysfunction  occurs  rapidly.

Patients can be classified in low or high risk group for IC injury. Patients who are intoxicated, LOC, amnesia, ¯GCS, on anticoagulants, seizure, skull fx, <or> age, distracting injury etc. warrant diagnostic studies.

Do not assume AMS is 2ry  to presence of  ETOH when you deal with head trauma - get head CT.

1. Diagnostic tools offered are:
    
1. CT -  is considered  in  high  and  moderate  risk  group   pt . In  low  risk  group  pt   there's a  subset  of  pts   hit  by   blunt  object (baseball   bat ,  steel  pipe )  that  had  no  skull  fx ,  no LOC , GCS  of  15  and  yet  had  significant   head  injury . According  ATLS,  CT  for  detection of  subarachenoid  sp  trauma  is  diagnostic  and  no  LP is  needed (as  compared  tonon  traumatic subarachnoid ).
    
2. MRI although not commonly used today,  has potential to become test of choice. As compared to CT,  it can detect non-anatomical damage such as contusion, DAI and also IC hemorrhage not detected by CT.
    
2. C-SPINE – few  studies   demonstrated   that  C - Spine  injury   occurred   in  only  1.2% - 3.2%.
    
3. SKULL  X - RAYS – not rewarding (see above)

1. General Trauma Protocol ( ATLS ) applies.
    
2. Special considerations:
1. Airway  -  in  case  ETT  is  considered   Lidocaine  1mg/kg  is  given  in  order  to limit   increase   in  ICP. Avoid   succinylcholine . Intubation is also indicated when GCS is < 8.
    
2. Breathing -  keep  PO2 >90 ,. Hyperventilation is no longer practiced and used if pt has dilated pupil, pasturing, worsening GCS, midline shift on head CT  and  PCO2  is kept at 25-35 mmHg.  Avoid PEEP.
3. Circulation: -  N/S  or  LR
                     -  Hypertension; aggressive treatment is not
                        recommended.
    
4. Elevate  head  to  30
    
5. Monnitol  for  herniation : 1-2 g/kg   over  15 - 20  min. The goal is to keep serum Osm 300-310 mOsm. Causes hypotension. Monnitol is used only when there is clinical or radiographic evidence of herniation
    
6. Seizure  - prophylactic phenytoin  17mg/kg   IV  may  be  initiated when obvious severe head trauma (depressed skull fx, penetrating head injury). Some authors say that neither the seizure nor  the possibility  of developing one are an indication to start prophylactic antiseizure medication.
    
7. Hyperthermia  -  has  disastrous  effect  on  head  injured  pt.  Pt  should  be  treated with  hypothermic  blankets   and  shivering   controlled    with  Chlorpromazine 10 - 25  mg IV.
    
8. Ca Channel Blocker - Nimodipine 60mg q4h x 21days. This is given only in SAH 2ry to congenital aneurysm or AV malformation . The medication is useful in treatment of  cerebral blood vessel spasm when given within  96hrs.
    
9. Prevent hyperglycemia
    
10. Steroids fell out of favor

GLASGOW  COMA  SCALE  (GCS)

NOTE!!! Motor response is the best motor response, i.e. if one hand doesn't move to pain stimuli  (1 point) but the other hand flexes (3 points) the "flexion"  being best response is taken into final scoring.

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