Neurologic  Localiza.on  for  M3s  

Eugene  Gan    

What  I  will  not  do  

•  Run  through  the  details  of  M1  and  M2  neuroanatomy    

•  Give  a  lecture  about  all  the  details  of  various  neurological  condi.ons  

What  I  will  do  

•  Deliver  an  approach  to  a  pa.ent  that  integrates  condi.ons  related  to  the  nervous  system  across  all  5  pos.ngs  in  M3  

•  Outline  clinically  important  aspects  of  neuroanatomy  that  will  aid  in  making  a  diagnosis  

•  Show  you  how  to  build  an  algorithm  for  neurologic  localiza.on  

•  How  to  wire  all  these  into  your  physical  examina.on  steps  

 

Reality  Check  

•  OSCE  Short  Cases    -­‐  Examine  either  UL,  LL  or  CN  -­‐  Examiner  determines  where  you  examine    •  OSCE  Long  Case/Real  Life    -­‐  To  examine  whatever  part  of  the  neurological  system  succintly  to  arrive  at  a  diagnosis.    

-­‐  History  determines  where  you  examine  

Outline  

•  Approach  to  diagnosis  in  Neurology  •  Clinically  Relevant  Neuroanatomy  •  Algorithms  and  Physical  Examina.on  

History,  physical  examina3on   Obtain  signs  &  symptoms  Syndromic  diagnosis     Movement  (including  coordina.on  &  fluidity)  

Soma.c  senses  (touch,  temperature,  propriocep.on,  nocicep.on)  Special  senses  (vision,  hearing,  balance,  smell,  taste)  Consciousness  (including  epilepsy)  Intellect  (including  behaviour,  language)  Mood  (including  autonomic,  endocrine)  

   

Anatomic  diagnosis  ‘Where’  

Pyramidal  System:  Brain  all  the  way  to  muscle  Cerebellar  system  Extrapyramidal:  Basal  ganglia  and  others  Limbic  and  hypothalamic  Cerebral  cortex  Sensory  system:  Receptor  all  the  way  to  thalamus  and  sensory  cortex      

Ae3ologic  diagnosis  ‘What’  

VITAMIN  CD      

Func3onal  diagnosis   Disability,  Ac.vity,  Par.cipa.on  

Approach  to  diagnosis  in  Neurology  

Diagrams  of  Neuroanatomical  Framework  

Clinically  Important  

NEURO  ANATOMY  

What  is  an  algorithm?    •  It  should  be  a  dichotomy  (if  not  3  to  4  branches  at  the  MOST)      •  Comprehensive  (At  every  branch-­‐out,  check  back  to  see  if  you  

have  covered  all  aspects  of  the  heading)      •  High  Yield  –  Can  be  dichotomized  based  on  a  clinical  tool,  

minimal  overlap  of  condi.ons  between  categories    •  Logical  -­‐  Should  follow  the  sequence  of  your  thought  process/

physical  examina.on      •  Portable  –  Simple,  pocket  sized,  not  too  difficult  to  remember  

at  the  bedside  

•  There  are  always  caveats  

Motor  System  

•  Pyramidal  à  Gross  Ac.on    •  Extra-­‐pyramidal  à  Fluidity  •  Cerebellar  à  Coordina.on  

hbp://ebooks.sinauer.com/blumenfeld2e/text.php  

Spinal  Reflex  Arc  

hbps://figures.boundless.com/5249/full/gy-­‐of-­‐animals-­‐a-­‐reflex-­‐arc.jpe  

UMN  from  Cerebral  Cortex  

Cranial  Reflex  Arc  

•  Who  here  has  seen  a  stroke  pa.ent  with  a  UMN  CN  5/9/10/11  palsy?  

•  Besides  Facial  Nerve  (lower  half  of  motor  nucleus)  and  Hypoglossal  nerve,  all  other  cranial  nerve  nuclei  have  bilateral  innerva.on.    

Examples  of  Reflex  Arcs  Spinal  -­‐  Anal  Sphinctor  Tone  (S2-­‐S4)  -­‐  Babinski,  Ankle  Jerk  (S1)  -­‐  Cremasteric  Reflex  (L2)  -­‐  Hoffman’s  (C8)  -­‐  Triceps  (C7-­‐8)  -­‐  Biceps  &  Brachioradialis  (C5-­‐6)    Cranial  -­‐  Gag  Reflex  (CN  IX-­‐X)  -­‐  VOR  (CV  XIII  –  CN  III/IV/VI)  -­‐  Corneal  Reflex  (CN  V1  –  VII)  -­‐  Jaw  Jerk  Reflex  (CN  V3  –  VII)  -­‐  Pupilliary  Light  Reflex  (CN  II-­‐III)      

Teaching  points  about  reflexes    1) Reflexes  do  not  breach  consciousness  (Brain  stem  as  a  repository  of  CN  nuclei)  

 2) An  hyper-­‐reflexic  jerk  (Nuclear)  should  prompt  you  to  think  upwards  (Supra-­‐nuclear)  

3)  A  hypo-­‐reflexic  jerk  should  prompt  you  to  think  of    -­‐  Afferent  -­‐  Efferent      

 

Pa.ent  

Case  1  •  His  back  pain  started  just  last  night.  Both  LL  were  weak  and  reflexes  were  down  bilaterally  –  Where  is  the  lesion?  

•  His  back  pain  has  been  going  on  for  the  past  3  You  no.ced  his  R  lower  limb  was  weak,  and  reflexes  were  down,  the  other  leg  was  fine.  Before  you  proceed  on  from  the  motor  examina.on  –  Where  could  the  lesion  be?    

•  What  if  his  back  pain  had  been  going  on  for  1  week  reflexes  were  up  on  the  R  leg?    

•  What  is  the  tone  of  the  anal  sphinctor  in  each  of  these  clinical  situa.ons?    

•   If  I  told  you  he  was  having  an  early  morning  headache  and  vomi.ng  in  the  past  4  weeks  and  your  examina.on  findings  were  the  same  (BL  LL  Hyper-­‐reflexia)  

Cord  Lesions  

•  Most  onen  Bilateral    •  Associated  with  a  sensory  level  •  Onen  associated  with  bladder  and  bowel  symptoms    

Cerebral  Cortex  

Case  2  For  some  reason  he  was  just  not  paying  aben.on  you  and  you  only  really  got  his  aben.on  when  you  went  over  to  the  len  side  of  the  bed.  Both  of  his  eyes  were  looking  to  the  len  as  well.  You  tried  to  ask  how  he  was  doing,  but  for  some  reason,  he  had  a  lot  of  difficulty  understanding  you  and  when  he  replied  you  it  completely  made  no  sense.  Where  is  the  lesion?        He  says  hey  hello  Doctor  so  nice  of  you  to  come  and  visit  me.  It’s  terrible  though,  I  seem  to  be  seeing  two  of  you  and  it’s  so  irrita.ng!  He  covers  one  eye  and  feels  a  lot  more  comfortable  and  you  guys  proceed  to  con.nue  your  chat.  He  tells  you  he  will  invite  you  the  next  Hari  Raya  to  feast  and  you  remind  him  not  to  eat  too  many  fried  chicken  wings.  Where  is  the  lesion?      

Pyramidal  Tract  

Corona  Radiata  

Internal  Capsule  

Cerebellar  System  

•  What  are  the  inputs?    •  Draw  a  broad  idea  of  the  pathway  •  Truncal  vs.  Peripheral  

Brain  Lesions  

•  Usually  Unilateral  signs  (unless  bilateral  hemispheric  condi.ons)  

•  Cor.cal  vs.  Subcor.cal  vs.  Brain  Stem  

Approach  to  UMN  pabern  of  weakness  

Unilateral  

UL  involved?  

Below  C8  C8  and  above  

T7  –  T12  

All  absent?    

Above  T7  

Bilateral  

Para-­‐Saggital  Meningioma  

Yes  No  Test  Reflexes  

in  Ascending  Fashion  

Approach  to  UMN  pabern  of  weakness  

Unilateral  

Cor.cal  

Cor.cal  Signs?  

Contralateral  LMN  

Check  CN  VII  

Ipsilateral  UMN  

Brain  Stem   Subcor.cal  

Bilateral  

No  Yes  

Brown  Sequard  (Hemi-­‐Cord)  Syndrome  

Case  3  

•  45  year  old  Chinese  lady  •  No  significant  PMH  •  1  day  history  of  sudden  onset  weakness,  numbness  and  pain  in  both  lower  limbs  

Sensory  System  •  Brain  à  Further  localize  aner  motor  system    •  Cord  à  Idea  of  sensory  level.  Dissocia.on  of  modali.es  

(DCML  and  ST)  

 •  Peripheral  Nervous  System  à  Most  common  situa.on  in  med  sch  where  sensory  system  examina.on  is  clinically  high  yield!!  

Peripheral  Nervous  System  

•  Anterior  Horn  Cell  •  Radicle/Root  •  Plexus  •  Peripheral  Nerve  •  Neuromuscular  Junc.on  •  Muscle  

Where  is  the  thalamus?  

Where  do  the  two  sensory  pathways  converge?    

Back  to  Case  3  

•  Which  subdivision  of  the  PNS  can  we  rule  out?  •  What  are  we  len  with?        

Motor  Exam  Power  3  on  R  side,  0  on  L  side  for    -­‐  Ankle  Plantar  Flexion  -­‐  Toe  Doriflexion  -­‐  Ankle  Dorsiflexion  -­‐  Ankle  Inversion  -­‐  Ankle  Eversion    What  nerves  supply  these  movements?    What  myotomes  supply  these  movements?    

Sensory  Exam  

Sensory  Deficit  

•  Specific  Nerve  Distribu.on  •  Glove  and  Stocking  •  Patchy  (Dermatomal)  •  Con.guous      

Dis.nguishing  Factors  

 •  L4/5  vs.  Common  Peroneal  Nerve  •  Scia.ca  in  Root  Lesion  

Some  Common  Logic  

Nerves of Pelvic Viscera: Male

Anterior vagal trunk

Posterior vagal trunkandCeliac branch

lnferior phrenic arteries and

Left gastric artery and gastric

Celiac ganglia, plexus, and trunk

Left aort icorenal ganglion

Superior mesenteric ganglion

Superior mesenteric artery and

Intermesenteric (aortic) plexus

Inferior mesenteric ganglion,artery and plexus

Ureter and ureteric plexus

Superior hypogastric plexus

Superior rectal artery and plex

Hypogastr ic ner

Nerve from inferiorhypogastr ic plexusto sigmoid and descendingcolon (parasympathetic)

Sacral splanchnic nerves(sympathetic) 1_Inferior hypogastric(pelvic) plexus -

Obturator nerveand artery

Ductus deferensand plexus

Vesical plexus

Rectal plexus

Prostatic plexus

Cavernous nervesof penis

T10 spinal nerve (ventral ramus)

te and gray rami communicantes

Diaphragm

Left renal arteryand plexus

L1 spinal nerve(ventral ramus)

1st , 2nd, 3rd lumbar splanchnic nerves

Crav rami communicantes

Sympathetic trunk and ganglia

5th lumbar splanchnic nerve

L5 spinal nerve (ventral ramus)

Lumbosacral trunk

Cray rami communicantes

S1 sp ina l nerve(ventral ramus)

ic sp lanchnicnerves(parasympathetic)

al plexus

Piriformis muscle

Cluteus maximusmuscle and sacro-tuberous l igament

Coccygeus (ischiococcygeus)muscle and sacrospinousligament

Pudendal nerve

ator ani muscle

nferior anal (rectal) nerve

Perineal nerve

Dorsal nerve of penis

Plate 41O

Posterior scrotal nerves

Innervation

Now,  how  do  I  prepare  and  work  out  my  own  algorithms  for  Neurological  

Cases?  

What  is  an  algorithm?    •  It  should  be  a  dichotomy  (if  not  3  to  4  branches  at  the  MOST)      •  Comprehensive  (At  every  branch-­‐out,  check  back  to  see  if  you  

have  covered  all  aspects  of  the  heading)      •  High  Yield  –  Can  be  dichotomized  based  on  a  clinical  tool,  

minimal  overlap  of  condi.ons  between  categories    •  Logical  -­‐  Should  follow  the  sequence  of  your  thought  process/

physical  examina.on      •  Portable  –  Simple,  pocket  sized,  not  too  difficult  to  remember  

at  the  bedside  

•  There  are  always  caveats  

Approach  to  LMN  Pabern  of  Weakness  

Proximal  

Sensory  Loss?  

Muscle  (Myotonia)    

Pure  Motor  Neuropathy  

 MND      

Type  of  Sensory  Loss  

Distal    

Sensory  Loss?  Yes  

No    

Glove  &  Stocking   Patchy  

PN  (Polyneuropathy)  

 Myelopathy  

(Lower  dermatomes)  

PN  (Entrapment,  MM)    

Dermatomal  (Root/Radicle)  

Approach  to  LMN  Pabern  of  Weakness  

Proximal  

Sensory  Loss?  

Muscle  (Dystrophy,  Myosi.s)  

 NMJ  (Fa.guable,  Ocular  Signs)  

 Pure  Motor  Neuropathy  

Peripheral  Nerve  (GBS  –  Ascending)  

 Plexus  

 Cord      

Distal    

Sensory  Loss?  

No  Yes  

Con.guous   Patchy  

Type  of  Sensory  Deficit  

Single  Nerve    

Dermatomal  (Radicals)  

   

Sepng  out  list  of  condi.ons  

•  Paeds  •  IM  •  GS  •  Ortho  •  Fam  Med  

Evalua.ng  a  pa.ent  

•  4  Aspects:  Medical,  Func.onal,  Social,  Psychological  

•  Medical  –  6  Cs  •  Func.onal  –  Body  func.on,  ac.vity,  par.cipa.on  

•  Social  –  Pa.ent,  Family,  Community    •  Psychological  

Approach  to  diagnosis  in  Neurology  History,  physical  examina3on   Obtain  signs  &  symptoms  

Syndromic  diagnosis     Movement  (including  coordina.on  &  fluidity)  Soma.c  senses  (touch,  temperature,  propriocep.on,  nocicep.on)  Special  senses  (vision,  hearing,  balance,  smell,  taste)  Consciousness  (including  epilepsy)  Intellect  (including  behaviour,  language)  Mood  (including  autonomic,  endocrine)  

   

Anatomic  diagnosis  ‘Where’  

Pyramidal  System:  Brain  all  the  way  to  muscle  Cerebellar  system  Extrapyramidal:  Basal  ganglia  and  others  Limbic  and  hypothalamic  Cerebral  cortex  Sensory  system:  Receptor  all  the  way  to  thalamus  and  sensory  cortex      

Ae3ologic  diagnosis  ‘What’  

VITAMIN  CD      

Func3onal  diagnosis   Disability,  Ac.vity,  Par.cipa.on  

Case  2  

Mr  Ahmad  65/M/Malay  Sudden  onset  weakness  

Inspec.on  

•  A  –  Alert  vs.  Drowsy  vs.  Comatose  (GCS),  Toxic?    •  B  –  Breathing  (Respi  Distress/Laboured,  Abdominal,  Deep/Shallow,  Kussmal,  Cheyne  Stokes)      

•  C  –  Colour  (Pale,  Cyano.c,  Jaundiced,  Plethoric)  •  D  –  Disability  (Func.onal  Aids)  •  E  –  Environment  (Vitals,  Suppor.ve,  Related  to  system)  

•  If  GCS  suddenly  became  very  poor,  what  would  you  be  concerned  about?  

•  What  would  you  do?    

Paberns  of  Disease  in  PE  

•  Raised  ICP:  Fundoscopy  (Bilateral  Papilloedema),  False  localizing  6th  nerve  palsy,  Decreased  Conscious  Level  (Re.cular  Forma.on  of  the  pons)  

•  Hernia.on:  New  Focal  Signs,  Cranial  Nerve  Reflexes  (E.g.  Fixed  and  Dilated  Pupil)  

Steps  

•  Tone    •  Reflexes  •  Power  •  Cerebellar  Signs  •  Sensory  Examina.on    •  Gait  

Swap  order  for  LMN  pabern  of  weakness  

Presenta.on  (Finally)  

•  Medical      

Func.onal    

Hemiparesis   Lost  use  of  R  hand  &  cannot  walk  steadily  

Can  no  longer  draw  famous  pain.ngs  to  earn  

a  living  

House  on  10th  Floor  House  –  Poor  

occupa.onal  safety  No  lin  landing  on  every  

floor    

Male,  50  Divorced  Lives  alone  

•  Social  –  Family,  Finances,  Si.ng  of  care  •  Psychological  –  Depression  in  stroke    

Some  Caveats  

•  ALS  -­‐  Pseudobulbar  Palsy  (UMN)  -­‐  LMN    in  periphery  

What  are  we  len  with?  

•  Cranial  Nerves  •  Visual  Fields  

How  about  our  cranial  nerves?  

•  Motor  Axis  S.ll  Applies!  (E.g.  of  Ptosis)    •  Brain  Stem    •  Course  within  the  cranial  cavity  •  Areas  of  convergence  with  other  cranial  nerves  

•  Course  out  of  the  cranial  cavity  

Loca3on   Possible  Ae3ologies  

Other  Cranial  Nerves  Involved  

Other  differen3a3ng  

signs  

Pons  

CP  Angle    

IAM  

Middle  Ear  

Stylomastoid  Foramen  

Paro.d  Gland  

Take  Home  Pointers  

•  Broad  Categories  •  Distal  to  Proximal:  Neuroaxis  

Homework  that  will  really  help  

•  Condi.ons  List  across  all  pos.ngs  •  Comparison  Table  classified  according  to  the  Neuroaxis  

 

Closing  the  Loop  

•  Send  in  to  me  at  eugene.gan.mingjin@gmail.com  

   

Resources  

•  Kumar  &  Clarke  8th  edi.on  (1081  to  1089)  •  Black  Book  of  Clinical  Examina.on  by  Prof  Erle  Lim  

•  Talley  O’  Connor  •  Blumenfield  Neuroanatomy  through  Clinical  Cases  

Feedback  

•  hbp://goo.gl/XUJXke