Neurological Assessment of the Neurological Assessment of the Comatose PatientComatose Patient

Galen V. Henderson, MDGalen V. Henderson, MDBrigham and WomenBrigham and Women’’s Hospitals Hospital

Director, Neuroscience ICUDirector, Neuroscience ICU

Harvard Medical SchoolHarvard Medical School

Neuro examNeuro examRemains a critical in the clinical decision-making process. Remains a critical in the clinical decision-making process. – Does the patient who just collapsed on the street have Does the patient who just collapsed on the street have

cardiac disease/cardiac arrest or an cerebral cardiac disease/cardiac arrest or an cerebral hemorrhage? hemorrhage?

– Does the patient with nausea and vomiting need a Does the patient with nausea and vomiting need a gastroenterology consult or a head CT to evaluate for a gastroenterology consult or a head CT to evaluate for a brain tumor and increased ICP?brain tumor and increased ICP?

OutlineOutline • Review Consciousness and Coma PathophysiologyReview Consciousness and Coma Pathophysiology

• Discuss major syndromes of impaired states of Discuss major syndromes of impaired states of consciousnessconsciousness

• Review how to examine the sedated and comatose patientReview how to examine the sedated and comatose patient

• Discuss the complete comatose examination – and Dx of Discuss the complete comatose examination – and Dx of death by neurological criteriadeath by neurological criteria

Case

• 56-year-old female underwent left hip arthroplasty

• In the PACU 7:15PM, she complained of pain and received 100 mcg of fentanyl.

• 9:30PM ~oriented to person/place/time, with a reported "intact" neurological exam and moving all extremities.

• She received some Toradol and fell asleep.

Case

• Nurses noted she was becoming increasingly somnolent.

• Around 1:00AM, She required face mask oxygen and she became poorly responsive (even to sternal rub).

• She then received Narcan and Flumazenil but did not respond.

• Per the PACU nurses, the patient had been on telemetry and continuous oxygen monitoring (with no alarms). An electrocardiogram showed sinus rhythm

ConsciousnessConsciousness• ConsciousnessConsciousness is multifacetedis multifaceted– Essential components are Essential components are alertnessalertness and and awarenessawareness of self of self

and the environmentand the environment

• AlertnessAlertness (arousability) as a prerequisite for other aspects of (arousability) as a prerequisite for other aspects of consciousness.consciousness.

• Full Full awarenessawareness an appropriate behavioral responses involve: an appropriate behavioral responses involve:– SensationSensation– PerceptionPerception– Memory functionMemory function– Attention (with links to motivation)Attention (with links to motivation)– CognitionCognition

LEVELS OF CONSCIOUSNESSLEVELS OF CONSCIOUSNESS• Alert Alert normal awake and responsive statenormal awake and responsive state

• Lethargic Lethargic easily aroused with mild stim. Can maintain arousal.easily aroused with mild stim. Can maintain arousal.

• Somnolent Somnolent easily aroused by voice or touch; awakens and easily aroused by voice or touch; awakens and follows commands; required stimulation to maintain arousalfollows commands; required stimulation to maintain arousal

• Obtunded/Stuporous: Obtunded/Stuporous: arousable only with repeated and arousable only with repeated and painful stimulation; verbal output is unintelligible or nil; some painful stimulation; verbal output is unintelligible or nil; some purposeful movement to noxious stimulationpurposeful movement to noxious stimulation

• Comatose Comatose no arousal despite vigorous stim, no purposeful no arousal despite vigorous stim, no purposeful movement- only posturing, brainstem reflexes often movement- only posturing, brainstem reflexes often absent/present, respirations may be varyingabsent/present, respirations may be varying

Characteristics of major clinical Characteristics of major clinical syndromessyndromes

CharacteristicsCharacteristics PVSPVS ComaComa Locked-in Locked-in SyndromeSyndrome

Self-awarenessSelf-awareness AbsentAbsent AbsentAbsent PresentPresent

Sleep-wake cyclesSleep-wake cycles IntactIntact AbsentAbsent IntactIntact

Motor functionsMotor functions No purposeful No purposeful movementmovement

No purposeful No purposeful movementmovement

Quadriplegia + Quadriplegia + pseudobulbar palsypseudobulbar palsy

Experience of Experience of sufferingsuffering

NoNo NoNo YesYes

Respiratory Respiratory functionfunction

NormalNormal VariableVariable Usually normalUsually normal

EEGEEG Suppressed or slowSuppressed or slow VariableVariable NormalNormal

Cerebral Cerebral metabolismmetabolism

Reduced by 50% or Reduced by 50% or moremore

Reduced by 50% or Reduced by 50% or moremore

NormalNormal

PATHOPHYSIOLOGY OF COMAPATHOPHYSIOLOGY OF COMA

• Bilateral diffuse hemisphere diseaseBilateral diffuse hemisphere disease

• Brainstem reticular formation disease Brainstem reticular formation disease

The ExaminationLevel of consciousness is then noted by the patients reaction to:– Calling of his/her name– Simple commands – Noxious stimuli such as tickling the

nares, supraorbital or sternal pressure, pinching the side of the neck or inner parts of the arms or thighs, or applying pressure to the knuckles

NEUROLOGICAL EXAM OBSERVATIONNEUROLOGICAL EXAM OBSERVATION

• Respiratory patternRespiratory pattern1. Normal 1. Normal 2. Periodic (Cheyne-Stroke or other)2. Periodic (Cheyne-Stroke or other)3. Hyperventilation (compensatory vs. primary)3. Hyperventilation (compensatory vs. primary)4. Apneustic (pontine)4. Apneustic (pontine)5. Ataxic (medullary)5. Ataxic (medullary)6. Apnea6. Apnea

• AutomatismsAutomatisms– 1. Good - yawn; sneeze1. Good - yawn; sneeze– 2. Bad - cough; swallow; hiccups2. Bad - cough; swallow; hiccups

Mental Status ExaminationMental Status Examination• Taking the history is 80% of the localizationTaking the history is 80% of the localization• ESSENTIALS OF HISTORYESSENTIALS OF HISTORY– Pace (i.e. rate of onset)Pace (i.e. rate of onset)– Toxins and drugs (alcohol, meds, CO)Toxins and drugs (alcohol, meds, CO)– TraumaTrauma– FeverFever– HeadacheHeadache– Similar episodes in the pastSimilar episodes in the past

Mental Status ExaminationMental Status Examination

• Level of consciousnessLevel of consciousness– Normal, depressedNormal, depressed

• OrientationOrientation– Person, place and timePerson, place and time

• AttentionAttention– Calculations, digit span, spelling Calculations, digit span, spelling ““worldworld”” backwards backwards

• MemoryMemory

NERUOLOGICAL EXAM CRANIAL NERVESNERUOLOGICAL EXAM CRANIAL NERVES

• I- not testable; smelling salts tests pain (V)I- not testable; smelling salts tests pain (V)• II - visual threat for fields & fundi II - visual threat for fields & fundi • III, IV, VI, VIIIIII, IV, VI, VIII

1. Pupils - size; reaction (No PERRLA)1. Pupils - size; reaction (No PERRLA)2. Eye movements - no head turning allowed 2. Eye movements - no head turning allowed

A. spontaneousA. spontaneousB. ice water caloricsB. ice water calorics

• V, VII - corneal reflexV, VII - corneal reflex• IX, X - gag reflex and swallowingIX, X - gag reflex and swallowing• XI, XII - not tested acutelyXI, XII - not tested acutely

Eyes are of great importance• Normal pupillary size, shape and light reflexes indicate integrity

of the midbrain structures– Loss of light reaction usually precedes enlargement of the

pupil

– The pupil may become oval or pear-shaped appear to be off center (corectopia) because of a differential loss of innervation of a portion of the pupillary sphincter

– As midbrain displacement continues, both pupils dilate and become unreactive to light as a result of the compression of the oculomotor nuclei in the rostral midbrain

– In the last step in the evolution of brainstem compression, there tends to be a slight reduction in pupillary size on both sides to 5mm or smaller

PUPILS:PUPILS: • CN II afferent, CN III efferent. Tests level of the midbrain as CN II afferent, CN III efferent. Tests level of the midbrain as

well as autonomic integrity. well as autonomic integrity. • Some patterns:Some patterns:

– Hypothalamus: HornerHypothalamus: Horner’’s (miosis, ptosis, and anhydrosis)s (miosis, ptosis, and anhydrosis)– Midbrain: midposition, fixedMidbrain: midposition, fixed– Peripheral III: usually unilateral, more dilated, fixedPeripheral III: usually unilateral, more dilated, fixed– Pons: pin point pupilsPons: pin point pupils– Medulla (lat): HornerMedulla (lat): Horner’’s- preserved response to lights- preserved response to light– Metabolic: in general metabolic derangements do not Metabolic: in general metabolic derangements do not

affect pupils. (Roving)affect pupils. (Roving)• The major exceptions are sympathomimetics and The major exceptions are sympathomimetics and

anti-cholinergics which dilate, and opiates which anti-cholinergics which dilate, and opiates which cause pin point pupilscause pin point pupils

Cranial Nerves 2

• Visual Acuity

• Visual Fields– Confrontation– Threat testing

• Fundoscopic examination

CN 2

Left Right

Vertical Eye MovementsVertical Eye Movements

EXAM OF EXAM OF CRANIAL NERVESCRANIAL NERVES

• I- not testable; smelling salts tests pain (V)I- not testable; smelling salts tests pain (V)• II - visual threat for fields & acuity; fundi II - visual threat for fields & acuity; fundi • III, IV, VI, VIIIIII, IV, VI, VIII

1. Pupils - size; reaction (No PERRLA)1. Pupils - size; reaction (No PERRLA)2. Eye movements - no head turning allowed 2. Eye movements - no head turning allowed

A. spontaneousA. spontaneousB. ice water caloricsB. ice water calorics

• V, VII - corneal reflexV, VII - corneal reflex• IX, X - gag reflex and swallowingIX, X - gag reflex and swallowing• XI, XII - not tested acutelyXI, XII - not tested acutely

Eye Movements-CN 3, 4, 6

• Describe the size and shape of pupils to light.

• Check for lid droop, lag, or retraction. • Ask the patient to follow a small

object at a distance of 2 ft • Move the target slowly in both

horizontal and vertical planes; observe any weakness, nystagmus

• Doll’s eyes/cold calorics reflex

Cranial Nerve 3,4 and 6

• CN 3– Pupilary constriction to direct/consensual light– Argyll-Robertson pupil

• Reacts to near vision but not to light

–Marcus-Gunn pupil• Impaired constriction to direct light and normal

consensual response

– Constriction to near vision (not accommadation)

– Swinging flashlight test

Eye Movements

• Movements are checked in all 6 directions of gaze

• Ask about diplopia• Conjugate gaze• Nystagmus• Primary gaze• Volitional eye movements

CN 5

• V1, V2, and V3

• Corneal Reflex Blink occurs if V and VII are intact Compare the sides for symmetry

CN 7

• Facial symmetry

• Look in particular for differences in strength of the lower versus upper facial muscles.

Types of Facial Weakness

CN 9, 10, 11 and 12

• Palatal elevation– Ahh

• Pharyngeal ('gag') reflex – Gag

• Swallowing/voice quality• Trapezius• Tongue protrusion

Palate and Tongue

EXAM OF THE EXAM OF THE MOTORMOTOR SYSTEM SYSTEM

• Spontaneous movement - compare sidesSpontaneous movement - compare sides• Induced movement (noxious stimuli)Induced movement (noxious stimuli)

– Paralysis - does not localizeParalysis - does not localize– Purposeful/NonpurposefulPurposeful/Nonpurposeful

• Antigravity postures (Antigravity postures (Posturing)Posturing)– Decorticate: Decorticate: extension LE, flexion at elbows/wristsextension LE, flexion at elbows/wrists

• Better prognosis than decerebrateBetter prognosis than decerebrate• Often without concomitant loss neuro-optho reflexesOften without concomitant loss neuro-optho reflexes• Usually lesion is above the midbrainUsually lesion is above the midbrain

– Decerebrate: Decerebrate: extension LE, extension LE, extension/pronation/adduction UEextension/pronation/adduction UE• Often with neuro-ophtho changesOften with neuro-ophtho changes• Most commonly lesion at level of midbrain or Most commonly lesion at level of midbrain or

diencephalondiencephalon

Motor

• Strength 0 = no movement1 = flicker or trace of contraction but no associated movement at a joint2 = movement with gravity eliminated3 = movement against gravity but not

against resistance 4 = movement against moderate resistance 5 = full power

EXAM OF THE EXAM OF THE SENSORYSENSORY SYSTEM SYSTEM

• Hemisensory deficitHemisensory deficit

• Level on the trunk - myelopathyLevel on the trunk - myelopathy

NEUROLOGICAL EXAM REFLEXESNEUROLOGICAL EXAM REFLEXES

• Proprioceptive (tendon jerks)Proprioceptive (tendon jerks)

• Nocioceptive (plantar; corneal)Nocioceptive (plantar; corneal)

• Antigravity (decerebration; decortication)Antigravity (decerebration; decortication)

Reflexes

• Commonly tested are:– Biceps (C5, C6)– Brachioradialis (C5, C6)– Triceps (C7, C8)– Patellar (L3, L4)– Achilles (S1, S2) – Reflexes are graded according to the following

scale:

0 = absent 1 = present but diminished 2 = normoactive 3 = exaggerated 4 = clonus

Extensor Planters

N Engl J Med 344:1215, April 19, 2001

DeathDeath• Cardiac death (the heart stops)

– Absence of radial, carotid or femoral pulses– Absence of heart tones at apex of heart by auscultation– Absence of breath sounds by auscultation– Pupils nonreactive– Ascertain that the patient does not rouse to verbal or

tactile stimuli

• Brain death (the brain stops)– irreversible loss of function of the brain, including the

brainstem– Exam is much more complicated

Evolution of Brain Death ConceptEvolution of Brain Death Concept• Uniform Determination of Death Act (1981)

– Death can be diagnosed by neurologic criteria– Does not define any of the specifics of the clinical diagnosis– There is a clear difference between severe brain damage and

brain death

• 1995: AAN Guidelines in Neurology (1995 45:1012.)– “…irreversible loss of function of the brain, including the

brainstem” – Specifically addressed

• clinical examination• validity of confirmatory tests• provided a practical description of apnea testing

Clinical Evaluation of Brain Death:Clinical Evaluation of Brain Death:• No Cerebral Response to Painful Stimulus

– Spinal Reflexes Permitted but no posturing allowed

• Absence of Brainstem Function– Tested by Cranial Nerve Examination – Interval Between Exams Arbitrary, Often 6 Hours– Adequate Vital Signs Required

• SpO2 over 90%• SBP over 90 mmHg

• Apnea Examination

• (Clinical examinations performed twice and apnea testing occurs once)

The Core of the ExaminationThe Core of the Examination• Part I: Coma

• Part II: Absence of brainstem reflexes– Pupillary Response to Light– Corneal Reflex– Gag Reflex – Cough Reflex– Occulocephalic Reflex (Dolls Eyes)/ Occulovestibular

Reflex (Cold Calorics)

• Part III: Apnea (inferior brainstem)

Apnea TestingApnea Testing• Prerequisites– Core temp > 36.5 C or 97 F– Systolic blood pressure > 90 mm Hg– Euvolemia or positive fluid balance in the

previous 6 hours– Normal pCO2 or arterial PCO2 > 40 mm Hg– Normal PO2 or preoxygenation to obtain

arterial PO2 > 200 Hg

Apnea TestingApnea Testing• Connect pulse oximeter and disconnect ventilator

• Deliver 100% O2, 6L/min into trachea

• Look closely for any movements

• Measure PO2 and PCO2 and pH after 8-10 min and reconnect ventilator

Prerequisites to rule outPrerequisites to rule out• Severe electrolyte imbalance• Acid-base or endocrine disturbance• Hypothermia ( < 32 oC or lower)• Hypotension• Absence of evidence drug intoxication,

poisoning, or neuromuscular blocking agents• Locked-in-syndrome

N Engl J Med 344:1215, April 19, 2001

Ancillary laboratory testsAncillary laboratory tests• Brain death is a clinical diagnosis

• Repeat clinical examination in 6 hours later is recommended but this interval is arbitrary

• Ancillary tests are not mandatory but desirable in patients in whom specific testing cannot be reliably performed or evaluated

Ancillary Tests --VascularAncillary Tests --Vascular• Conventional Cerebral Angiography

– Absence of Filling Beyond the Circle Of Willis– Pro: Considered “Gold Standard” in Diagnosis of Brain Death1

– Con: Requires Extensive, Specific Manpower, Transport out of ICU

• Cerebral Blood Flow Scan– Technetium-99 Radioisotope Study– Pro: Can be Done Bedside– Con: Requires Specific Manpower, Poor Sensitivity on Posterior

Circulation

• Transcranial Doppler Ultrasonography– Absence of Diastolic Flow, Reverberating Flow Indicate High ICP– Con: Many Patients Lack Adequate Insonation Windows

– 1.Morenski JD, et al. J Int Care Med 2003;18(4):211-221

Ancillary Tests -- FunctionalAncillary Tests -- Functional• Electroencephalography (EEG)

– Absence of Electrical Activity for 30 Minutes– Specific Criteria For Sensitivity of Recording– Pro: Noninvasive, Readily Available– Con: Significant Interference from ICU Devices

• Somatosensory Evoked Potentials– Absence of N20-P22 Response from Median Nerve Stimulation

Commonly Used– Pro: Relatively Widely Available– Con: Confounded by Nerve Injury, Tests Limited Regions of Brain

Brain Death around the WorldWijdicks EFM. Brain death worldwide: Accepted fact but no global consensus

in diagnostic criteria NEUROLOGY 2002;58:20-25

• Guidelines of 80 countries reviewed• Legal standards on organ transplantation present in 69% (55

of 80 countries)• Practice guidelines for brain death for adults in 88%

– 50% guidelines require >1 physician to declare– All guidelines specified exclusion of confounders, presence of

irreversible coma, absent motor response, and absent brainstem reflexes

– Apnea testing required in 59%– differences in time of observation and required expertise of

examining physicians– Ancillary laboratory testing mandatory in 28 of 70 (40%) guidelines

Case• Unresponsive, eyes closed with no arousal• Brainstem:– Pupils were reactive– Absent corneals and oculocephalic reflex– No cough, gag

• Motor– Left upper extremity with decerebrate posturing

• Bilateral extensor planter reflex• Overbreathing the ventilator

SummarySummary • Review Consciousness and Coma PathophysiologyReview Consciousness and Coma Pathophysiology

• Discuss major syndromes of impaired states of Discuss major syndromes of impaired states of consciousnessconsciousness

• Review how to examine the sedated and comatose patientReview how to examine the sedated and comatose patient

• Discuss the complete comatose examination – and Dx of Discuss the complete comatose examination – and Dx of death by neurological criteriadeath by neurological criteria

Thank You For Your AttentionThank You For Your Attention