Coma, vegetative and locked in syndrome

Department of Neurosurgery
Tribhuvan University Teaching Hospital
Coma, vegetative state and locked
in syndrome
Sandesh Dahal
2077.04.18
Introduction

Parts of consciousness
 Consciousness has two parts
 They are
 Wakefulness or arousal
 Content or Awareness to self and the environment
 both absent- state of coma
 Only wakefulness present- state of vegetative state
 Both present, but can’t execute motor or verbal response to them- locked in syndrome
consciousness

State of consciousness after brain injury
 Coma
 Vegetative state aka unresponsive wakefulness syndrome
 Akinetic mutism
 Locked in syndrome
 Minimal responsive state
consciousness

Coma
 Defects in either
 Thalamus bilaterally
 Brainstem, central upper pons or midbrain or
 Diffuse lesions in both cerebral hemispheres
coma

 State of unarousable unresponsiveness with (sedation must be excluded)
 Closed eyes either spontaneous or with stimuli
 Don’t follow commands
 Don’t demonstrate goal directed behavior
 Don’t verbalize
 Can’t sustain visual pursuit
coma

Coma
 No single score defines coma.
 90% of people with GCS < 8 fits into the definition.
 And mostly none with GCS >9 fits to this definition.
 So, GCS <8 is almost like operational definition of coma for practical purposes.
coma

Glasgow coma scale
coma

coma

Etiology
 Broadly can be divided into
 with localizing features
 Without localizing features
 Without localizing features
 With meningism
 Without meningism
coma

Etiology
 Toxic or metabolic
 Electrolyte imbalance- Na, Ca, BUN, HE
 Endocrine- glucose, DKA, HHS, myxedema, addisonian crises
 Vascular- vasculitis, DIC, hypertensive encephalopathy
 Toxic- alcohol, drugs like narcotic overdose
 Infectious and inflammatory- meningitis, encephalitis, sepsis, lupus cerebritis
etc
coma

 Neoplastic- leptomeningeal carcinomatosis
 Nutritional- Wernicke’s encephalopathy
 Metabolic diseases- porphyria, lactic acidosis
 Epileptic- status and post ictal state
coma

causes…..
 Structural
 Vascular-
 Bilateral cortical or subcortical infarcts
 Occlusion of bilateral hemispheres eg bilateral carotid stenosis
 Bilateral diencephalic infarcts
 Infectious- abscess with mass effect, HSV encephalitis
coma

Structural…
 Trauma- contusion, edema
 Neoplastic
 Herniations causing compression of RAS
 Raised ICP
 Acute midline shift due to hematomas
coma

Vegetative state
 show the behaviors of arousal, but
 No ability to interact with the environment
 They may have
 Periods of eye opening either to stimuli or spontaneous
 Subcortical response to pain like posturing, tachycardia or diaphoresis
 Subcortical motor response like grasp reflex
 Brainstem functions like sleep wake or normal respiratory function, swallowing
and temperature regulation is present
 Eye movements without visual tracking
Vegetativestate

Diagnosis of vegetative state
 Three prime features
 Sleep wake cycle present
 All the responses are identified as reflex activities
 No awareness and no meaningful response to stimuli
ANDREWS K, The vegetative state − clinical diagnosis, Postgraduate Medical
Journal 1999;75:321-324.
Vegetativestate

The vegetative and minimally conscious states: Consensus-based criteria for
establishing diagnosis and prognosis, NeuroRehabilitation 19 (2004) 293–298 293
IOS Press
Giacino, Joseph T.
Vegetativestate

 If vegetative state > 1 month- persistent vegetative state
 If >3 months in non traumatic injury- chronic vegetative state
 If >12 months in traumatic injury- chronic vegetative state
Vegetativestate

Locked in syndrome
 Its not a vegetative or coma state
 But it is an important differential
 Many cases are mistaken for diagnosis
 Lesion
 Ventral pons
 Results in normal dorsal midbrain and pons function
Lockedinsyndrome

 The dorsal midbrain and pons including reticular center is intact
 The person can feel self and environment
 The person is alert and aware of self and environment, but
 Can’t respond, because there is damage to bilateral cortiospinal and corticobulbar
tracts
Lockedinsyndrome

 The only possible response is
 Blinking of eye- variable
 Up and downgaze of eye
 Otherwise, there is quadriparesis and inability to use the muscles of facial expression
 Horizontal eye gaze is not possible
 ‘Alphabet in the air’- communication technique
Lockedinsyndrome

Coma- core examination
Meningism
Respiration
Examinationincoma

 Cheyne-stokes- crescendo-trail off- pause
 Occurs in diencephalic lesions and bilateral cerebral hemispheric dysfunction
 Cluster breathing- rapid irregular-apneic spells
 Lesion in high medulla or lower pons
 Apneustic- pause at full inspiration
 Pontine lesions
 Ataxic/biots breathing- no pattern in rate and depth
 In medullary lesion
Examinationincoma

Pupil
 Record direct and consensual light
Examinationincoma

 Bilateral pinpoint pupil- medullary lesion
 Bilateral fixed and dilated- subtotal medulla damage, hypoxia and hypothermia
 Midposition fixed- extensive medulla damage
Examinationincoma

 Ocular deviation
 Bilateral conjugate deviation- frontal lobe, looks away from destructive lesion
and looks towards irritative lesion
 Pontine lesion- looks away from the lesion
 Downward deviation- perinaud syndrome
 Unilateral down and out- IIIrd nerve palsy, uncal herniation
 Unilateral inward deviation- Vith nerve palsy
Examinationincoma

 Spontaneous eye movements
 Windshield wiper eyes- non localizing, but indicates IIIrd and MLF are intact
 Pingpong gaze- deviation to left right at 3-5/sec, and pause for 2-3 sec,
indicates bilateral cerebral dysfunction.
 INO- ipsilateral eye cant adduct. Lesion in MLF
Examinationincoma

 Ocular bobbing- repetitive rapid vertical down movement
 Occurs in brainstem lesion
 Oculovestibular reflex- head 30 deg, intact TM, 60-100 ml of ice water
 Intact brainstem- tpnic conjugate eye deviation to side of cold stimulus
 No response- toxic or metabolic eg barbiturates and muscle relaxants
 Assymmetric- infratentorial lesion
 Nystagmus without clonic deviation- psychogenic coma
Examinationincoma

 Dolls eye response- don’t do if cervical spine is not ruled out
 Normal is contraversive eye movement
 Caloric absent and dolls eye present in cases of streptomycin toxicity and bilateral
vestibular schwannoma
Examinationincoma

 Motor response
 Asses corticospinal tract
 Symmetric- in metabolic causes
 Asymmetric – supratentorial lesions
 Inconsistent- seizure or psychiatric
 Hyporeflexia- myxedema coma
Examinationincoma

 Posturing
 Decorticate- cortical or subcortical lesions
 Decerebrate- brainstem or below lower midbrain
 Arms flexed and legs flaccid- pontine tegmentum
 Arms flaccid legs appropriate- anoxic injury
Examinationincoma

Examinationincoma

 Ciliospinal reflex- Noxious stimuli cause pupil to dilate
 Bilateral- metabolic
 Unilateral- 3rd nerve palsy
 Bilateral absent- non localizing
Examinationincoma

Thank you

Coma, vegetative and locked in syndrome

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