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Concussion and  chronic  headache  disorders   Sports-­‐related  concussion  has  gained  increasing  attention  and  a  welcomed  growing  awareness   amongst  the  sports  medicine  community  in  recent  years.  Contact  sports  have  a  higher  incidence  of   concussion  due  to  their  nature  and  inherent  risks.  This  places  players  in  many  vulnerable  situations   for  a  variety  of  head  injuries  including  abrasions,  contusions,  lacerations,  fractures,  intra-­‐cerebral   trauma  and  concussions.   Concussion  is  defined  as  a  trauma  induced  alteration  in  mental  status  caused  by  a  direct  or   transmitted  force.  It  has  a  rapid  onset  with  a  short-­‐lived  impairment  of  neurological  function  and   contrary  to  a  commonly  held  belief,  may  present  with  or  without  a  loss  of  consciousness.  It  is  a   functional  disturbance,  but  is  likely  to  have  both  structural  and  chemical  changes,  which  are   presently  not  detectable  by  conventional  neuro-­‐imaging  techniques.     Post-­‐traumatic  headache  is  the  most  common  post-­‐concussive  symptom  and  the  most  frequent  type   of  post-­‐traumatic  pain  associated  with  mild  traumatic  brain  injury.  It  often  forms  part  of  a  post-­‐ concussion  syndrome  encompassing  a  variety  of  somatic  and  psycho-­‐behavioral  symptoms   (dizziness,  drowsiness,  changes  in  sleep  patterns,  behavioral  or  mood  changes,  and  difficulty  with   memory,  concentration,  attention,  and  thinking.)     In  the  majority  of  patients,  the  post-­‐concussion  syndrome  is  self-­‐limiting  with  the  post-­‐traumatic   headache  and  accompanying  symptoms  gradually  improving  and  spontaneously  resolving  over  a   period  of  weeks.  However,  in  a  minority  of  patients,  it  may  become  chronic  and  persistent,  requiring   a  comprehensive  and  multidimensional  management  approach  including  pharmacologic   intervention,  physical  rehabilitation,  and  cognitive-­‐behavioral  therapy.     Concussion  may  precipitate  the  onset  of  headaches,  exacerbate  pre-­‐existing  headaches  or  trigger  the   first  attack  in  susceptible  individuals.  Patients  with  a  strong  family  history  of  migraines  may  be  at  an   increased  risk  for  developing  these  chronic  headaches.  Interestingly,  post-­‐concussive  headaches   appear  to  be  more  strongly  associated  with  relatively  milder  initial  injuries.  The  reasons  for  this   association  are  uncertain.   The  headache  in  post-­‐concussive  states  usually  occurs  within  a  day  of  the  injury,  but  may  be  delayed   for  weeks  and  continue  for  months  post  injury.  The  post-­‐concussive  headache  typically  presents   similarly  to  one  of  the  primary  non-­‐traumatic  headache  disorders:  tension-­‐type,  migraine-­‐like,   cluster-­‐like  or  mixed  headache  syndromes.     Controversies  still  exist  as  to  the  exact  etiology  and  underlying  patho-­‐physiology  of  post-­‐concussive   headaches.  Current  hypotheses  suggest  shared  common  pathways  with  primary  headache  disorders   relating  to  neuro-­‐chemical  dysfunction  and  dys-­‐regulation,  neuronal  disturbances  and  peripheral   cervical  pain  pathways.  The  threshold  for  symptoms  to  present  is  thought  to  be  lowered  with   recurrent  and  multiple  concussive  episodes,  which  in  turn  may  lead  to  cumulative  damage   presenting  with  long-­‐term  consequences  (permanent  neuro-­‐cognitive  deficits,  depression,  memory   loss,  Alzheimer’s).   The  trigeminal-­‐vascular  system  may  be  activated,  injured,  or  disturbed  by  non-­‐penetrating,  mild   traumatic  brain  injury.  When  triggered,  the  meningeal  arteries  dilate,  which  stimulates  the  peri-­‐ vascular  sensory  trigeminal  nerves.  Stimulation  of  the  trigeminal  nerves  results  in  the  release  of   inflammatory  chemicals,  which  in  turn  produces  further  meningeal  artery  dilation  and  also  activation   of  the  pain  generator  in  the  lower  brainstem  and  upper  cervical  cord  (C1-­‐C3  cervical  segments   connect  to  the  trigeminal  vascular  nucleus).     Accompanying  the  post-­‐concussive  headache  is  the  very  frequent  presence  of  neck  pain  or  occipital   neuralgia  type  pain,  which  either  can  exacerbate  or  be  the  source  of  the  symptoms.  This  may  be   secondary  to  soft  tissue  damage  (ligaments  and  muscles),  but  may  involve  intervertebral  disc  

damage and,  occasionally  nerve  root  compression.  Trigger  points  and  accompanying  muscle  spasm   are  frequently  found  in  the  trapezium,  posterior  cervical,  and  occipital  areas.   There  is  scant  literature  with  which  to  select  treatment  for  post-­‐concussive  headaches  and   consequently  treatments  are  based  on  those  strategies  prescribed  for  similar  but  etiologically   distinct  headache  disorders.   A  multidisciplinary  approach  is  required  in  the  treatment  of  post-­‐concussive  headaches  and   combining  both  “central”  and  “peripheral”  interventions  has  become  the  most  effective  therapeutic   modality.  Abortive  and  preventative  medication,  NSAIDs  and  muscle  relaxants,  physiotherapy,   chiropractic  care,  relaxation  techniques,  acupuncture  and  biofeedback  are  all  available  options  but   treatment  should  be  individualized  and  tailored  towards  managing  all  the  presenting  symptoms.   Patients  also  require  education,  support,  and  counseling  to  facilitate  a  sense  of  involvement  in  the   management  of  their  post-­‐concussive  headache  as  well  as  a  sense  of  control  over  them.  Reasonable   expectations  should  be  explained  to  avoid  frustrating  therapeutic  limitations.  Reassurance  that  this   condition  will  improve  is  important,  as  symptoms  in  the  majority  of  cases  progressively  lessen  over   time.  Psychotherapy  may  be  needed  to  facilitate  the  process  of  adjusting  to  (or  coping  with)  chronic   post-­‐concussive  headaches.     Delayed  recovery  or  persistent  post-­‐concussive  headaches  may  result  from  inadequate  or  ineffective   treatment,  overuse  of  analgesic  medications  resulting  in  analgesia  rebound  phenomena,  or  co-­‐ morbid  medical  or  psychiatric  disorders  (post-­‐traumatic  stress  disorder,  insomnia,  substance  abuse,   depression,  or  anxiety).  Psychological  and  legal  (compensation  neurosis)  factors  should  also  be   considered  in  certain  cases.     Post-­‐concussive  headache  is  a  complex  issue  and  thus  early  management  by  experienced   neurologists  or  other  physicians  who  have  training  in  treatment  of  concussion,  traumatic  brain   injuries  and  post-­‐concussion  syndrome  is  important  in  improving  the  patient’s  quality  of  life  in  the   shortest  period  of  time  possible.     References  on  request.