Approach to a Child with Coma

Prof Rashmi Kumar

Department of Pediatrics,

KG Medical University,

Lucknow

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

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

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

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

Coma: Pathophysiology

Diffuse bilateral cerebral lesion

Mass lesion compressing ARAS

Coma: Etiology

CNS Causes: Structural• CNS infections• Mass lesions CSF obstruction + volume• Trauma• Vascular

CNS Causes: Functional• Seizures• Hypoxic - ischemic injury

Coma: EtiologyExtracranial causes Metabolic

• Systemic shock

• hypo/ hypernatremia

• hypoglycemia

• diabetic coma

• hepatic

• uremic

• hypoxia

• Reye’s

• Respiratory failure

• Acidosis/ alkalosis

• Hyperosmolality

• Inherited metabolic disorders

Coma: EtiologyExtracranial causes Drugs

• Barbiturates• benzodiazepines• opioids• tricyclics• antihistamines

• Iron• Salicylates• aceraminophen• Metals

Coma: EtiologyExtracranial causes

Toxic • Lead• gram negative endotoxemia• Shigella• CO poisoning• pesticides• alcohol/ ethylene glycol

Coma: EtiologyExtracranial causes

Endocrine– hypothyroidism– diabetic

Miscellaneous– hypertensive encephalopathy– heat stroke– hypothermia

Psychogenic

Coma: Immediate Management

Is resuscitation required?• A – airway prevent tongue falling

back, suction• B – breathingrespiratory support,

oxygen• C- circulationiv fluids, monitor BP,

vasopressors• If any evidence of poisoning GL

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?

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

Coma : Neurological Examn

Painful stimuli- strong pinch, pressure on nail bed, pressure on globe

Glasgow Coma Scale:Best Motor Best Verbal Eye opening1. none none none2. extension to incomprehensible to pain pain sounds3. flexion to inappropriate to call pain words 4. withdraws confused speech spontaneous 5. localises well oriented6. Moves on command

Coma : Neurological ExamnModified Coma Scale for children < 2 yrsBest Motor Best Verbal Eye opening1. none none none2. extension to moaning to to pain pain pain3. flexion to crying to to call pain pain 4. withdraws irritable cry spontaneous5. localises coos, babbles6. Moves on command

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

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

Structural vs functional coma

• Meningeal signs• Focal deficits• Brain stem reflexes

lost• Pupils unequal or

fixed dilated

• Absent• Absent• Present

• Semidilated and reactive

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

Coma: TreatmentTreat the causeSupportive care – antipyretics, anticonvulsantsManagement of ICP

Mannitol – 0.25 – 1 gm/kg of 20% solution (1.25 – 5 ml/kg) bolus ivFrusemideDiamox, glycerineSteroids – esp vasogenic edemaHyperventilation lowers CBVCPPMaintain PCO2 between 25 – 30 mm Hg

Nursing care:PositionNutrition Care of eyesCare of skinChest physiotherapyCare of bowel & bladderPhysiotherapy

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

Coma: Diagnosis of Brain DeathImportance(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

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.

A. History: determine the cause of coma to eliminate remediable or reversible conditionsB. Physical examination criteria:1. Coma and apnea2. 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 apnea3. Patient must not be hypothermic or hypotensive4. Flaccid tone and absence of spontaneous or induced movements excluding activity

mediated at spinal cord level5. Examination should remain consistent for brain death throughout the predetermined

period of observation

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)

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

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

Unilateral unresponsive pupil is found in:

a)      Morphine poisoning

b)      Impending trantentorial herniation

c)       Belladona poisoning

d)      Brain death

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

Signs of raised intracranial tension include all except:

a)      Hypertension

b)      Shallow breathing

c)       Bradycardia

d)      Papilledema

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