Coma

Amy R. Brooks-Kayal, MDEric Marsh, MD, PhD

Coma - BASICS

Coma - description

Coma is defined as a state in which the patient is unresponsive with eyes closed, usually lasting <24 hours. Coma is a medical emergency, and immediate attention/intervention is required for abnormalities in breathing, circulation, glucose, or electrolytes.

• Coma should be differentiated from:
• Lethargy: A patient who is incoherent but arousable and has a tendency to sleep
  • Stupor: A state of excessive somnolence; the patient is responsive only transiently to noxious stimuli
  • Delirium: A confused, agitated patient with fragmented attention, concentration, and memory
  • Vegetative state: Chronic state with clear sleep/wake cycles and no signs of cognition
  • Locked-in: Must be distinguished from coma; cognitive functions are intact, although the patient may appear unconscious

• Be aware of psychogenic coma and locked in states (see “Description”).
• Loss of protective airway reflexes signals impending respiratory failure.

Coma - epidemiology

Trauma and near drowning are the leading causes of coma in children, and boys are more often victims of trauma/near drowning than are girls.

Coma - pathophysiology

Dysfunction of the reticular activating system in the brainstem or bilateral cerebral dysfunction

Coma - etiology

• Trauma: Bleeds (epidural/subdural, intracerebral), cerebral swelling, diffuse axonal injury
• Intoxication: Seizure or psychotropic medications, street drugs
• Hypoxia/ischemia
• Infection: Meningitis, encephalitis, toxic shock, subdural empyema, systemic shock
• Metabolic disorders: Hypoglycemia (salicylate or ethanol intoxication, hyperinsulinemia); diabetic ketoacidosis (rarely neurologic deterioration on initiation of insulin therapy); Reye syndrome; electrolyte abnormalities (Na, K, Ca, Mg); hepatic/uremic encephalopathy; inborn errors of metabolism; hormonal abnormalities (thyroid, adrenal, pituitary); hypothermia/hyperthermia
• Tumor
• Seizure: Nonconvulsive status, spike and wave stupor
• Vascular: Hezorrhage from arteriovenous malformation (AVM), aneurysm, coagulopathy, infarction, cerebral venous thrombosis, hypertensive encephalopathy
• Hydrocephalus: Ventriculoperitoneal (VP) shunt obstruction, mass/bleed obstructing ventricular outflow

Coma - DIAGNOSIS

Coma - signs & symptoms

Coma - history

• Head trauma
• Ingestion/drugs/toxins (in home, given by acquaintances)
• Fever (and other symptoms of infection or preceding viral illness)
• Headache (nausea, vomiting, and other signs of increasing pressure or meningitis)
• Seizures
• Diabetes
• Pre-existing neurologic disease including previous episodes of coma

Coma - physical exam

• Vital signs: Look for bradycardia, hypertension, and abnormal respiratory pattern (Cushing triad for cerebral herniation).
• Look for signs of head trauma: Raccoon eyes, battle sign (ecchymosis at mastoid equals basilar skull fracture), retinal hemorrhages, bulging fontanelle
• Signs of meningitis: Nuchal rigidity, Kernig and Brudinski signs
• Neurologic: Verbal or motor response to voice, touch, pain; eye opening/fixation; pupil symmetry/reactivity; spontaneous movements/posturing; worsening of these signs may indicate increased intracranial pressure (ICP)
• Reflexes: Specific to rostral brainstem function (pupillary light reflex, corneal reflex, jaw jerk) and to caudal brainstem function (oculocephalic reflex [eye deviation with passive head rotation], gag, spontaneous respirations)

Coma - tests

Coma - lab

Initial blood studies obtained with placement of an IV line include:

• Glucose, electrolytes, blood urea nitrogen/creatinine, calcium, CBC
• Arterial blood gas
• Toxicology screen
• Ammonia, liver transaminases

Coma - imaging

• Radiology: 1st, noncontrast head computed tomography scan to look for hemorrhage, may be followed by contrasted images or magnetic resonance imaging to look for infection/mass lesions
• Cervical spine series (CT or lateral and anterior–posterior radiograph studies): Indicated if evidence of trauma by history or on examination. Spine must be stabilized until injury is ruled out.
• MRI brain: To look for causes if other work-up is unrevealing.

Coma - diag proced-surgery

• Lumbar puncture: To rule out infection, bleed; defer until after computed tomography if focal exam or signs of increased ICP. If question of traumatic tap, spin out red cells promptly and examine fluid for xanthochromia.
• EEG: Helpful to rule out nonconvulsive status epilepticus
• Electrophysiologic studies: Somatosensory evoked, brainstem auditory evoked and visual evoked potentials may be helpful for diagnosis and prognosis.

Coma - pathological findings

Varies depending on etiology

Coma - differencial diagnosis

Disorders mimicking coma:

• Psychogenic coma: Patient may resist passive eye opening, regards self in mirror, and avoids passive arm fall over face.
• Locked-in state: Complete paralysis with normal cerebral function. May occur in severe neuromuscular disorders (acute polyneuropathy) or in ventral pontine lesions (hemorrhage, demyelination)

Coma - TREATMENT

Coma - initial stabilization

• 1st priority is stabilization of respiratory and hemodynamic status (airway, breathing, and circulation management).
• Endotracheal intubation: Often required for airway protection and adequate oxygenation
• Large-bore IV lines should be placed and isotonic fluids administered as needed to replace intravascular volume and maintain adequate blood pressure.
• If finger-stick glucose determination is low, give 2–4 mL of 25% dextrose (D25) per kilogram IV (D10 if young infant).
• If ingestion is suspected, administer naloxone (0.01 mg/kg IV).
• Evidence of increased ICP:
  • Hyperventilate to decrease blood carbon dioxide to 25–30 torr and give mannitol (0.5–1 g/kg IV). Can also give dexamethasone, 1–2 mg/kg IV
  • Fluids given should be isotonic and the volume limited to maintain adequate perfusion.
  • Elevate head to 30°above horizontal to maximize cerebral venous drainage.
  • Hospitalization is in the intensive care unit for close monitoring for changes in respiratory status or signs of increased ICP.
  • IV antibiotics should be given if infection is suspected.

Coma - general measures

As per underlying etiology of the coma

Coma - special therapy

Coma - phys therapy

Physical therapy for range of movement while patient is comatose and during recovery should be implemented.

Coma - surgery

Neurosurgical intervention may be required in cases of head trauma, hemorrhage, mass lesion, or hydrocephalus. Neurology consultation is usually indicated.

Coma - FOLLOW UP

Coma - prognosis

Prognosis depends on underlying etiology. Complete recovery frequently seen after toxic–metabolic coma. In contrast, patients with coma resulting from severe head trauma or hypoxic injury often have significant neurological sequelae and require long-term physical, occupational, and cognitive therapies.

Coma - complications

Acute coma:

• Respiratory failure
• Deep venous thrombosis
• Pneumonia (aspiration and infectious)

Coma - patient monitoring

When patient falls into coma, care should be in an ICU. Patients in a coma for prolonged periods may be managed in step down units or floors depending on associated issues.

Coma - bibliography

1. Jacinto SJ, Gieron-Korthals M, Ferreira JA. Predicting outcome in hypoxic-ischemic brain injury. Pediatr Clin North Am. 2001;48:647–660.
2. Tasker RC. Neurolocal critical care. Curr Opin Pediatr. 2000;12:222–226.
3. Trubel HK, Novotny E, Lister G. Outcome of coma in children. Curr Opin Pediatr. 2003;15:283–287.

Coma - CODES

Coma - icd9

780.01 Coma

Coma - FAQ

• Q: What is the role of the electroencephalogram in the diagnosis of coma?
• A: Electroencephalogram is useful in diagnosis of psychogenic coma (should be normal), in coma from nonconvulsive status epilepticus (shows electrographic seizures), and in possible herpes encephalitis (temporal or frontal sharp activity).
• Q: Should anticonvulsants be given to comatose victims of trauma?
• A: Although no clear evidence exists that anticonvulsants improve outcome or reduce incidence of posttraumatic seizures, they are often given for posttraumatic intracranial hypertension, bleeding, and/or edema as seizures are known to raise ICP.

Book Source Details

• Book Title: The 5-Minute Pediatric Consult
• Author(s): M. William Schwartz MD; et al.
• Year of Publication: 2008
• Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.

Other Book Chapters Related to Coma

Read excerpts from these other book chapters related to Coma:

Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Williams & Wilkins.

More About Causes of Coma

• Back to symptom: Coma: Introduction (review 823 causes)
• Next Book Extract About Coma: Medications causing Coma
• All Book Extracts: All Online Book Extracts for Coma

More About This Book: Title: The 5-Minute Pediatric Consult Authors: M. William Schwartz MD; et al. Publisher: Lippincott Williams & Wilkins Copyright: 2008 ISBN: 0-7817-7577-9

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