1. The document discusses various levels of impaired consciousness ranging from confusion to coma and defines them. It also describes the anatomy of the reticular activating system and two patterns of coma - diffuse cerebral injury or focal brainstem injury. 2. Specific causes of diffuse cerebral injury or focal brainstem injury that can lead to coma are provided. Evaluation of a comatose patient involves assessing level of consciousness, brainstem reflexes, and determining if focal neurological signs are present. 3. Management may involve giving thiamine, dextrose, naloxone and flumazenil in cases of diffuse injury without a known cause. For focal injuries, neuroimaging is important to identify structural

1. ΔMS
Ken Uchino, M.D.
Assistant Professor of Neurology
UPMC Stroke Institute

2. DEFINITION
 COMA: the complete absence of
awareness of self and the
environment even when the subject
is externally stimulated

3. ΔMS
 Confusion
 Drowsy—Inability to sustain wakefulness
without external stimuli
 Obtundation—aroused by vigorous stimuli,
interacts briefly
 Stupor—arounsed only by vigorous and repated
stimuli, but not interactive
 Coma

4. ΔMS
 IT’S A SPECTRUM:
ALERT
”DROWSY”
”OBTUNDED”
”STUPOROUS”
COMATOSE
 ….much better to just describe what you
see!

5. ANATOMY
 RETICULAR ACTIVATING
SYSTEM:
– a primitive, evolutionarily conserved
diffuse (reticular) network of neurons
throughout the brain
– some more concentrated areas “nuclei” or
“centers”
– originates in brainstem
– ascends through diencephalon via which it
connects to rest of brain

6. ANATOMY
 Two major anatomic patterns of coma:
1. Diffuse cerebral injury (2/3)
or
2. Focal injury to the brainstem
(1/3)

7. DIFFUSE CEREBRAL
INJURY
 Trauma
– Concussion, diffuse axonal injury
 Vascular
– Global hypoxia-ischemia
– Hypertensive encephalopathy
 Infectious
– Sepsis
– Meningitis, encephalitis
 Epileptic
– Post-ictal state
– Non-convulsive status epilepticus

8. DIFFUSE CEREBRAL
INJURY
 Metabolic:
– Electrolyte abnormalities:
 pH disturbance
 Hyper or hyponatremia
 Hyper or hypoglycemia
 Hyper or hypocalcemia
– Organ failure
 liver, kidney
– Thiamine or vitamin B12 deficiency
– Drug intoxication or withdrawal

9. FOCAL BRAINSTEM INJURY
 Direct hit to the brainstem
– Brainstem stroke or tumor
 Secondary pressure onto the brainstem
– Trauma
 Subdural or epidural hematoma
– Vascular
 Subarachnoid hemorrhage
 Intracerebral hemorrhage
– Neoplasm
– The mass raises intracranial pressure and herniation
onto the brainstem.

10. Case 1
 50 yo man sent confused from homeless
shelter.
 History not obtainable. ? EtOH abuse
 PE: Afebrile, tachycardic. Mildy
hypertensive.
 Really groggy. When aroused, very
confused, dysarthric.

11. Case 1
 CT normal
 Labs: WBC 15, otherwise CBC, Chem 7,
LFTs normal.
 EtOH level undetcable,
 Urine tox: negative for drugs of abuse.
 Presumed dx: toxic encephalopathy, EtOH
withdrawal

12. Case1
 Febrile in the evening.
 The resident attempts to perform LP.
 After attempt at decubitous position…
 Attempted sitting up (with help of nurse and
attending physician)…
 Green fluid comes out.

13. ΔMS H&P
 1. Recent events:
– When was the patient last seen?
– How was the patient discovered?
– Were there any preceding neurologic complaints?
– Was there any recent trauma or toxic exposure?
 2. Medical istory
 3. Psychiatric history
 4. Medications
 5. Use of drugs or alcohol

14. General Physical Exam
 Vitals
– Is there a fever?
– Severe hypertension?
 Skin
– Trauma, jaundice, needle marks
 Head
– Fractures, lacerations
 Neck (do not manipulate if suspect Fx!)
– Stiffness?
 Neurologic exam…

15. Coma exam
 Describe:
 Observe then stimulate:
– Level of consciousness
 Brain stem Exam
– Fundi, Pupils, Corneals, EOM, Gag and cough
 Extremities

16. Coma Exam: Level of
Consciousness
 Awake
 “Opens eyes to voice,” “grimaces to pain,”…
 Localizes pain—pain where ?(central vs.
peripheral)
 Any abnormal response? Patterned response?
– Flexor posturing (Decorticate)
– Extensor posturing (Decerebrate)
– Myoclonus?
 Respiratory pattern?
– “Riding the vent” vs. overbreathing

17. Respiration
 Cheyne- Stokes pattern
– diencephalic/ diffuse
– CHF
 hyperventilation
– midbrain
 apneustic pattern
– pons
 ataxic respiration
– medulla
 …interesting, but not really useful in the
field!

18. Testing LOC
 First, a verbal command:
– Specific command (hard): “Show me two
fingers!”
 not “squeeze my hand”
– Midline command (easier): “Open your eyes”
 eye lid apraxia?
 Try it again with a noxious stimulus

19. Testing LOC: Noxious
– Head:
stimulus
 ear pinch, cotton swab to nares, supraorbirtal ridge pressure,
pin to nares
– Body
 Sternal rub, shoulder pinch
 Areolapossibly the most sensitive spot you can find…It also
helps you identify the malingering patients.
– Extremities
 Pinch arm or calf, Nailbed pressure, plantar stimulation
 Response
 Localization
 Withdawal
 Flexor (decorticate) posturing
 Extensor (decerebrate) posturing

20. Posturing
 Extensor posturing (Decerebrate)
– Hips and shoulders extend, adduct, and internally rotate
– Knees and elbows extend
– Forearms hyperpronate, Wrists and fingers flex
– Feet plantar flex and invert
– Trunk extends, Head retracts
 Flexor posturing (Decorticate)
– Shoulders adduct, internally rotate, and flex slightly;
elbows flex; forearms pronate; and wrists and fingers
flex
– Lower extremities extend, adduct, and internally rotate
– Hip, knee, and ankle may flex in a spinal reflex known
as triple flexion

21. A picture speaks…
• It means that the
patient is not
conscious.
• The cortex isn’t
communicating.
• It’s not well
localizing.

22. Brains stem reflexes: pupils
 critical in distinguishing metabolic from
structural etiologies of coma

23. Brainstem reflexes: pupils
 Dilated, unreactive pupils
– third nerve compression
– sympathetic agonist drugs (cocaine)
– cholinergic antagonists (atropine)
 Small reactive pupils +/- Horner’s syndrome
– hypothalamus/diencephalon injury
– damage to sympathetic input
– opiates, cholinergic agonist drugs

24. Brainstem reflexes: pupils
 fixed midposition pupils
– midbrain
– i.e. loss of sympathetic and para- sympathetic
inputs (Edinger- Westphal)
 small unreactive/ minimally reactive pupils
– pons, cholinergic poisoning

25. Brain stem reflexes:
extraocular movements
 Horizontal conjugate gaze is mediated by:
– Frontal eye fields
– Pontine gaze centers
 In unresponsive patients, conjugate eye
movments can be elicited by:
– Oculocephalic reflex (Doll’s eye)
– Oculovestibular reflex (Cold water calorics)

26. Brain stem reflexes: EOM
 First, observe at rest
– Roving
– Not moving
– Gaze deviation
 Hemispheric lesion:
“eyes look at the lesion”
 Pontine damage: “eyes
look away from the
lesion”
 Seizure: “eyes look
away from the lesion.”

27. Brainstem reflexes: EOM
 Conjugate
– A good sign, but do they move appropriately?
 Dysconjugate
– A bad sign, but why?
 Just relaxed muscles?
 Impaired EOM?

28. Brainstem reflexes: EOM
 Next, try the reflexes:
 1. Oculocephalic (aka Doll’s eye) reflex:
– Presence indicates that the brainstem is intact
 2. Coculovestibular (caloric) reflex:
– Tonic deviation towards the cold ear

29. Brainstem reflexes
 Corneal Reflexes:
– CN 5 & 7
– pontine lesion
 Gag Reflex:
– afferent component
 IX
– efferent component
X

30. Brainstem reflexes
EYE
 Pupils:
– II in
– III out
 EOM:
– VIII in
– III, (IV), VI out
 Corneals:
– V in
– VII out
 Gag:
– IX in
– X out

31. Extremities
 Reflexes
– Deep tendon reflexes
– Response to noxious stimuli:
 Is it a reflex or withdrawal?
 Plantar response—triple flexion

32. Glasgow Coma Scale
Eye Opening
None 1
To Pain 2
To Speech 3
Best Verbal Response
Spontaneous 4
None 1
Best Motor Response Incomprehensible sounds 2
None 1 Inappropriate words 3
Extension (at elbow) 2 Confused 4
Abnormal Flexion 3 Oriented 5
Withdrawal 4
Localizes pain (attempts to 5
remove stimulus) Total Score = 3-15
Obeys commands (simple 6
commands)

33. Case 2 (JJ)
 78 yo woman stopped talking and had right
sided weakness.
 On the way to the hospital, she vomited.
Became unresponsive.
 PMH: macular degeneration, anxiety.
 Pt was intubated in the ER. Received lasix
for HTN of 218/98.

34.  BP 180/90 P 84 afebrile
 General PE: unremarkable, except intubated.
 Neurologic: No spontaneous movements or eye
opening. Not following commands.
 Noxious stimuli:
– She localizes pain in the left UE. She has purposeful
movement in the left upper extremity (squeezing hand
sponaten.).
– On the right side, extensor posturing to pain on the
right UE and triple flexion in the right lower extremity.
 Brain stem:
– Her pupils are 2 mm and reactive. She has left gaze
preference, but has spontaneous eye movements.
Visual field is difficult to assess. She has gag reflex
intact.

35. CATEGORIZE
 Nonfocal exam with brainstem intact
– Reactive pupils, full eye movements, symmetric motor
responses.
– Suggests diffuse cerebral damage.
 Focal hemispheric signs
– Contralateral hemiparesis, gaze paresis
– Suggests structural CNS lesion
 Focal brain stem signs
– Abnormal pupil reactivity, cranial nerve signs, motor
posturing.
– Suggests brainstem lesion

37. MANAGEMENT
 In the case of a diffuse cerebral injury with
no known cause…give the coma “cocktail”:
– THIAMINE 100 mg IV
– 50% DEXTROSE 50ml IV
– NALOXONE (Narcan) 0.4-0.8 mg IV
– (FLUMAZENIL (Romazicon) 0.2-1.0 mg IV)

38. MANAGEMENT
 In the case of focal hemispheric or
brainstem signs, obtain neuroimaging..
– CT
– MRI
 And look for signs of increased intracranial
pressure

39. Case 3 (CM)
 75 yo F found down by husband.
 She has left hemiparesis, dysarthric. C/o HA.
 PMH: GERD, no HTN
 SH: Husband: she drinks and smokes as much as she can.
 PE: BP 106/90
 A+O x3. Follows commands. Speech fluent, but
dysarthric. She has left neglect.
 Pupils 63 mm. Left VF cut. Corneal and gag reflexes
present. Facial sensation is diminished on the left. Right
eyelid droop (old).
 Flaccid hemiplegia. Sensation: neglect. Deep tendon
reflexes 1 throughout. Toes going up bilaterally.

40. Right thalamic ICH & IVH
CT: on Nov 5
at 1450

41. Case 3
Day 2
 BP 169/94
 No eye opening to stimuli. Not following
commands.
 Eyes downward and to the left. Pupils 3mm
reactive. Corneal reflexes present.
 Left hemiplegic. RUE purposeful
movement. RLE withdrawal. Bilateral
upgoing toes.

42. ↑ICH & hydrocephalus
• CT: Nov 6 at
4:50 am
• Subsequently
Intubated
• Ventriculostomy

43. Case 3
Day 3
 ICP shot up early morning. Got head CT:
 Exam off propofol x 5min:
 LUE extension and RUE flexion to pain
centrally as well as peripherally.
 Triple flexion in LE bilaterally.
 Pupils 2mm reactive. Left gaze deviation
but some spontaneous roving movements.
Corneal reflex intact.

45. Case 3
Day 4
 Off propofol for 24 hours
 BP 148/68 P 120 RR 14/13
 Unresponsive to sound or pain
 Pupils fixed at 4mm, corneal reflexes
present. Absent gag reflex.
 Triple flexion in LE.
 Pt expired later that day.

46. Herniation Syndromes
 Central Transtentorial
– paratonic rigidity of lower extremities
– pinpoint pupils (sometimes)
– hyperreflexia/ spontaneous triple flexion responses
– waning level of consciousness
– sudden cardiac or respiratory arrest/ death

47. Herniation Syndromes

48. Herniation Syndromes

49. Herniation Syndromes
 Lateral Transtentorial/Uncal:
– most common in those with temporal lobe
masses (tumor, hematoma,…)
– ipsilateral dilated pupilthen bilateral
– hyperreflexia/ spasticity
– ipsilateral hemiplegia (Kernohan’s notch)
– hemianopsia (PCA infarct)
– brainstem compression/ death

50. Herniation Syndromes

51. Herniation Syndromes

52. Herniation Syndromes
 SUBFALCIAL HERNIATION
– ipsilateral and/or contralateral
paratonic rigidity
– LE paralysis (once completed)
– akinetic mutism (bilateral ACA)
 TONSILLAR HERNIATION
– downward cerebellar herniation
– nausea, vomiting, hyperreflexia
– sudden respiratory arrest

53. Herniation Syndromes

54. Herniation Syndromes

55. Herniation Syndromes
 Upward cerebellar herniation:
– nausea, vomiting, hyperreflexia
– SCA infarction syndrome
– hyperventilation
– brainstem compression/ coma/ death
 Transcranial Hernation:
– skull fracture, craniotomy
– ischemia of adjacent cortex (strangulation)

57. Herniation Syndromes

58. Case 4
 35 yo man unresponsive.
 Pt was just booked for some incident. At
police station, found with empty pill bottle.
Pt unresponsive. No known medical
history.

59. Case 4
 CT head normal
 Labs:
– Urine tox for drugs of abuse normal (opiates,
amphetamines, cocaine, tricyclics), salicylate and
acetaminophen levels undetectable.
 PE:
– Vitals normal
– General exam: shackled to stretcher
 Blood in back
– Unresponsive to voice, pain. Brainstem reflexes intact.
Extremity reflexes in tact.

60. Techniques
 Let arm drop on face
 Tickle nares
 Surprise the patient

61. Case 4
 Wouldn’t let eyes be opened
 ER residents had attempted LP without
lidocaine. (The blood in back).
 He only flinches with needle in his back.
 I further macerate his back and succeed in
getting CSF—normal
 Angry man next morning.

62. Case 5
 40 yo woman from rural Washington state
 Presents to local ER c/o “throat swelling.”
She also c/o blurred vision. The exam is
reported to be fairly unremarkable initially.
But in the ER she worsens and develops
respiratory arrest.
 No signficant past medical history. No
asthma or allergies.

63. Case 5
 She is intubated, given steroids for presumed
allergic reaction or angioedema. She is transferred
to Seattle.
 In medical ICU she is on vent. She is treated for
aspiration pneumonia, reactive airways. She
remains unresponsive. Comatose. Never wakes
up.
 Several days later neurology is consulted for post-
anoxic encephalopathy. Is she going to wake up?

64. Case 5
 Exam: Vitals normal. Riding the vent.
– Unresponsive to pain, sound.
– Pupils unreactive, absent corneals, cold calorics
absent, no gag. Areflexic in extremities
 CT of head: normal.
 Is she brain dead?

65. Brain Death:
 the complete and irreversible cessation of all
brain function
 absent pupillary responses (fixed,
midposition)
 absent oculocephalic responses
 absent corneals, gag
 absent calorics response
 absent motor response
 absent respiration (pCO2>60)

66. Brain Death:
Necessary Tests
 APNEA TEST
– preoxygenate with 100% O2
– maintain O2 through ETT with cannula etc.
– two minute duration
– pCO2 of 60mmHg or higher adequate
 COLD WATER CALORICS
– never do in a noncomatose person
– ice water 30cc to each ear
– wait 2 minutes for response before other side

67. Case 5
 Wait, she moves her toe!

68. Brain Death:
Pitfalls
 no drugs or hypothermia to explain a
precondition of diagnosis
 absent pupillary responses
– anticholinergic drugs, especially atropine in
cardiac arrest
– NM blockade
– preexisting eye disease
 absent oculocephalics
– ototoxic/ vestibular toxins

69. Brain Death:
Pitfalls
 apnea
– NM blockade
– post- hyperventilation
– phrenic nerve palsies/ diaphragm paralysis
 no motor activity
– NM blockade
– locked in syndrome
– sedatives

70. Brain Death:
Confirmatory Tests
 Confirmatory tests are NOT necessary for the
diagnosis. Tests necessary if the checklist
incomplete.
– Trauma, hemodynamic instability
 Tests:
– EEG with special array, sensitivity settings
 ICU artifact can create problems
– cerebral blood flow (Nuc Med)
– Transcranial Doppler ultrasound
– Evoked potential studies
 notlegally required to render futile care to a
dead person

71. Summary
 Get good History from surrogate
 Examine
 Is it focal or diffuse?