1. Coma is defined as a state of unconsciousness from which the patient cannot be aroused. It results from diffuse or focal injuries to the brain. 2. The document discusses the pathophysiology, etiology, examination, investigations, management, and diagnosis of brain death in patients presenting with coma. 3. Key points include differentiating structural from metabolic comas, evaluating for reversible causes, monitoring vital signs and neurological exam including brain stem reflexes, treating increased intracranial pressure, and confirming brain death through apnea testing and clinical criteria.

1. Approach to a Child with Coma
Prof Rashmi Kumar
Department of Pediatrics,
KG Medical University,
Lucknow

2. Coma: Definition
• Derived from the Greek word ‘Koma’ or
deep sleep
• Various grades – ‘spectrum’
• State of altered consciousness with
reduced capacity for arousal and reduced
responsiveness to visual, auditory and
tactile stimulation

3. • The word coma should be differentiated
from
– Syncope (transient alteration of consciousness)
– Seizure

4. Coma : Pathophysiology
• Normal consciousness is maintained by integrity of
certain areas of the cerebral cortex, thalamus and
brain stem
• Altered consciousness due to
– Diffuse lesions of cerebral cortex (metabolic, toxic,
hypoxic)
– Focal lesions of ARAS - central core of brain stem

5. Coma: Pathophysiology
• Diffuse insult to both cerebral hemispheres
(metabolic/toxic/hypoxic/ischemic)
or
• focal lesion affecting ascending reticular activating
system (ARAS) located in upper pons, midbrain &
diencephalon. Affected by compression (herniation)
Lesion in one cerebral hemisphere will not produce coma
ICT generalised ischemia (CPP=MAP-ICT)
focal ARAS damage by herniation

6. Coma: Pathophysiology
Diffuse bilateral cerebral
lesion
Mass lesion compressing
ARAS

7. Coma: Etiology
CNS Causes: Structural
• CNS infections
• Mass lesions  CSF obstruction +  volume
• Trauma
• Vascular
CNS Causes: Functional
• Seizures
• Hypoxic - ischemic injury

8. Coma: Etiology
Extracranial causes
Metabolic
• Systemic shock
• hypo/ hypernatremia
• hypoglycemia
• diabetic coma
• hepatic
• uremic
• hypoxia
• Reye’s
• Respiratory failure
• Acidosis/ alkalosis
• Hyperosmolality
• Inherited metabolic
disorders

9. Coma: Etiology
Extracranial causes
Drugs
• Barbiturates
• benzodiazepines
• opioids
• tricyclics
• antihistamines
• Iron
• Salicylates
• aceraminophen
• Metals

10. Coma: Etiology
Extracranial causes
Toxic
• Lead
• gram negative endotoxemia
• Shigella
• CO poisoning
• pesticides
• alcohol/ ethylene glycol

11. Coma: Etiology
Extracranial causes
Endocrine
– hypothyroidism
– diabetic
Miscellaneous
– hypertensive encephalopathy
– heat stroke
– hypothermia
Psychogenic

12. Coma: Immediate Management
Is resuscitation required?
• A – airway  prevent tongue falling
back, suction
• B – breathingrespiratory support,
oxygen
• C- circulationiv fluids, monitor BP,
vasopressors
• If any evidence of poisoning  GL

13. Coma : Quick History & Examn
• Circumstances?
• Duration & onset? Acute in CNS infection, trauma,
seizure, poisoning, metabolic, vascular
• H/o poisoning?
• H/o trauma?
• H/o fever?
• H/o seizure?
• Past medical history
– H/o seizures in the past?
– H/o known endocrine disorder?
– H/o headache/vomiting/visual symptoms?

14. Coma: Quick History & Examn
• Vitals
• Fever
• BP
• S/o shock
• S/o  ICP bradycardia, hypertension
• Respiration  rapid in acidosis & CNS lesions also
• General Physical:
– Evidence of trauma, injury, tongue bite
– Jaundice
– Breath - for odor of ketones, fetor hepaticus etc
– Skin peticheae, exanthem
– Dry, flushed skin in belladonna poisoning
– Moist skin with salivation in organophosphorus poisoning
• Complete systemic exam

15. Coma : Neurological Examn
Painful stimuli- strong pinch, pressure on nail bed, pressure on globe
Glasgow Coma Scale:
Best Motor Best Verbal Eye opening
1. none none none
2. extension to incomprehensible to pain
pain sounds
3. flexion to inappropriate to call
pain words
4. withdraws confused speech spontaneous
5. localises well oriented
6. Moves on
command

16. Coma : Neurological Examn
Modified Coma Scale for children < 2 yrs
Best Motor Best Verbal Eye opening
1. none none none
2. extension to moaning to to pain
pain pain
3. flexion to crying to to call
pain pain
4. withdraws irritable cry spontaneous
5. localises coos, babbles
6. Moves on
command

17. Coma : Neurological Examn
• Meningeal signs
• Tone/posturing
– Decerebrate- lesion in upper pons
– Decorticate- b/l cortical lesion with preservation of brain stem
function
– Flaccidity – when all cortical & brain stem function till
pontomedullary junction are lost
• Fundus
• Pupils
– Pinpoint in pontine lesions/morphine poisoning
– B/l fixed dilated in terminal state, severe ischemic damage,
atropine/belladonna poisoning
– U/l unreactive pupil ? transtentorial herniation
– Pupils generally small, equal & reactive in toxic/metabolic causes

18. Coma : Neurological Examn
• Cranial nerves
– 6th nerve palsy – false localizing sign
– u/l 3rd – impending herniation
• Deficits – suggest lesion in brain
• S/o ICP
– hypertension/bradycardia/abnormal breathing (Cheyne Stokes,
hyperventilation, apneustic, ataxic)
– papilledema
– posturing
– cranial nerve palsies
• Brain stem reflexes:
– Doll’s eye response
– Oculovestibular reflex
– Corneal reflex

19. Structural vs functional coma
• Meningeal signs
• Focal deficits
• Brain stem reflexes
lost
• Pupils unequal or
fixed dilated
• Absent
• Absent
• Present
• Semidilated and
reactive

20. Coma: Investigations
• Counts
• Blood glucose, urea, electrolytes, acid base
• Ammonia, liver function, lactate
• Toxicology
• Lumbar puncture – CI if ICP. Abnormal in
CNS infections
• Cultures
• EEG – usually non specific
• Imaging – r/o mass lesion

21. Coma: Treatment
Treat the cause
Supportive care – antipyretics, anticonvulsants
Management of ICP
Mannitol – 0.25 – 1 gm/kg of 20% solution (1.25 – 5 ml/kg) bolus iv
Frusemide
Diamox, glycerine
Steroids – esp vasogenic edema
Hyperventilation  lowers CBVCPP
Maintain PCO2 between 25 – 30 mm Hg
Nursing care:
Position
Nutrition
Care of eyes
Care of skin
Chest physiotherapy
Care of bowel & bladder
Physiotherapy

22. Persistent vegetative state:
• patients after recovery from coma return to a
wakeful state without cognition/ awareness of
environment
• Children who remain in this state for > 3
months do not regain functional skills
• Causes –
anoxia/ischemia/metabolic/encephalitic
coma/head trauma
• Survival indefinite with good nursing care

23. Coma: Diagnosis of Brain Death
Importance
(American Academy of Neurology, 1995)
Prerequisites:
– Cessation of all brain function
– Proximate cause of brain death is known
– Condition is irreversible
Cardinal features:
• Coma
• Absent brain stem reflexes
– Pupillary light reflex
– Corneal reflex
– Oculocephalic
– Oculovestibular
– Oropharyngeal
– Apnea
• Confirmatory tests (optional)
– Cerebral angiography
– Electroencephalography
– Radioisotope cerebral blood flow study
– Transcranial Doppler ultrasonography
• 2 examinations – interval depends
• One/two physicians

24. Apnea Test
• Prerequisites:- Core temperature > 36.5O C (97o F).
- Systolic blood pressure > 90 mm Hg (Adults only).
- 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 mm Hg).
• Connect a pulse oximeter. Disconnect the ventilator or place the patient on CPAP at an
appropriate level or place a cannula at the level of the carina and administer 100% O2
endotracheally at 8L per minute.
• Look closely for respiratory movements abdominal or chest excursions that produce
adequate tidal volumes).- Measure arterial PO2 , PCO2 , and pH after approximately 8
minutes (10 minutes for children). Resume mechanical ventilation.
• Absence of spontaneous respiratory effort with PCO2 20 mm Hg > baseline (PCO2 > 60
mm Hg) confirms apnea and supports the diagnosis of death. If respiratory efforts are
present, the test is inconsistent with brain death and should be repeated. For children, if
the rise in PCO2 fails to reach 60 mm Hg, perform the test again for a duration of 15
minutes.- If the blood pressure becomes unstable or significant oxygen desaturation and
cardiac arrhythmias are present during testing, resume ventilation. Immediately draw an
arterial blood sample. If PCO2 > 60 mm Hg or the increase is 20 mm Hg > baseline
normalized PCO2, the apnea test is consistent with brain death. If not, the result is
indeterminate. A confirmatory test may be useful.

25. A. History: determine the cause of coma to eliminate remediable or reversible conditions
B. Physical examination criteria:
1. Coma and apnea
2. Absence of brain stem function
(a) Mid-position or fully dilated pupils
(b) Absence of spontaneous oculocephalic (doll's eye) and caloric-induced eye movements
(c) Absence of movement of bulbar musculature, corneal, gag, cough, sucking and rooting
reflexes
(d) Absence of respiratory effort with standardized testing for apnea
3. Patient must not be hypothermic or hypotensive
4. Flaccid tone and absence of spontaneous or induced movements excluding activity
mediated at spinal cord level
5. Examination should remain consistent for brain death throughout the predetermined
period of observation

26. Observation period according to age:
• 7 days to 2 months: Two examination and EEGs 48 hours apart
• 2 months to 1 year: Two examination and EEGs 24 hours apart or one
examination and an initial EEG showing ECS combined with a
radionuclide angiogram showing no CBF.
• More than 1 year: Two examinations 12 to 24 hours apart; EEG and
isotope angiography are optional
• (No criteria for neonates < 7days of age)

27. MCQ
1. Cerebral Perfusion Pressure equals:
a) Mean arterial pressure + intracranial pressure
b) Mean arterial pressure - intracranial pressure
c) Intracranial pressure – Mean arterial pressure
d) None of the above

28. 2. The following is true about Glasgow Coma Scale:
a) The highest score is 10
b) Lowest score is 3
c) There are 5 possible scores for Best Motor Response
d) Lowest score is 0

29. Unilateral unresponsive pupil is found in:
a) Morphine poisoning
b) Impending trantentorial herniation
c) Belladona poisoning
d) Brain death

30. A 7 year old child is brought to the emergency in coma. On
deep painful stimulus there is no verbal response, no eye
opening and slight extension of limbs. What is his
Glasgow Coma Score?
a) 7
b) 9
c) 5
d) 4

31. Signs of raised intracranial tension include all
except:
a) Hypertension
b) Shallow breathing
c) Bradycardia
d) Papilledema

32. Prerequisites for diagnosis of brain death
include all except:
a) Cessation of all brain function
b) Flat EEG
c) Proximate cause of coma is known
d) Condition is irreversible