765CHAPTER 62 Coma and Depressed Sensorium TABLE 62 6 Laboratory Evaluation Test Abnormality Possible Etiology of Coma Tier 1 Labs (Immediate, Results With Rapid Turnaround) Blood glucose Hypoglycemia[.]
CHAPTER 62 Coma and Depressed Sensorium 765 TABLE 62.6 Laboratory Evaluation Test Abnormality Possible Etiology of Coma Tier Labs (Immediate, Results With Rapid Turnaround) Blood glucose Blood gas Hypoglycemia Endocrinopathy Fasting Severe illness/sepsis Inborn error of metabolism Hyperglycemia Diabetic ketoacidosis or hyperosmolar hyperglycemic state Metabolic acidosis Inborn error of metabolism Renal failure Sepsis Respiratory acidosis Hypoventilation due to increased intracranial pressure, narcotic or other toxic ingestion Hypocalcemia Hypomagnesemia Hyponatremia Seizures, status epilepticus Hyponatremia or hypernatremia Dehydration Carboxyhemoglobin Carbon monoxide poisoning Tier Labs (Intermediate, Results Within Longer Turnaround) Complete blood count Leukocytosis Infection, inflammation, stress Anemia Intracranial hemorrhage Lead encephalopathy Polycythemia Stroke Thrombocytosis Stroke Thrombocytopenia Disseminated intravascular coagulation Hypocalcemia Hypomagnesemia Seizures, status epilepticus Elevated urea Dehydration, uremia, renal failure Transaminitis Reye syndrome Hepatic dysfunction or injury from sepsis, shock, or intoxication leading to hepatic encephalopathy Serum osmolality Hyperosmolality Toxic ingestion, hyperosmolar hyperglycemic state Coagulation profile Coagulopathy Disseminated intravascular coagulation, intracranial bleeding Serum ammonia, lactate, pyruvate Hyperammonemia, increased lactate or pyruvate Inborn errors of metabolism (urea cycle defect, organic acidemia) Serum electrolytes Carnitine or acyl carnitine Disorder of fatty acid metabolism Serum amino acids Disorder of amino acid metabolism Urine organic acids Organic acidemia Thyroid hormone Low Hashimoto thyroiditis Urine toxicology (with attention to institutionspecific panels) Serum drug levels (of specific suspected agents) Cultures (blood, urine, tracheal, and/or cerebral spinal fluid) Infection Pregnancy Tier Labs (Not Routine, Delay in Results) Serum antiepileptic medication levels Subtherapeutic drug levels suggesting status epilepticus Supratherapeutic drug levels leading to altered mental status Virology Infection 766 S E C T I O N V I Pediatric Critical Care: Neurologic fractures suggestive of trauma, and careful retinal examination may reveal the presence of retinal hemorrhages, raising suspicion for nonaccidental trauma Brainstem auditory, visual, and somatosensory evoked potentials (SSEPs) may help gauge the extent of injury Treatment Goals: Initial and Ongoing Pathophysiology following brain injury occurs in two phases: primary and secondary Primary brain injury refers to the initial insult, whether it is ischemic, anoxic/hypoxic, excitotoxic, or shear injury, each potentially resulting in irreversible neuronal cell injury or death The only available treatment is prevention Secondary brain injury occurs in otherwise salvageable brain tissue as a result of cerebral hypoxia, hypoperfusion, hypoglycemia, intracranial hypertension, prolonged excitotoxicity, oxidative stress, infection, or inflammation and may result in further neuronal damage The goal of therapy is to prevent secondary brain injury As detailed in the Initial Treatment of the Comatose Child section, the major tenets of treatment must focus on (1) stabilization of airway; (2) breathing with adequate oxygenation and ventilation; (3) circulation with establishment of vascular or intraosseous access, fluid resuscitation and correction of hypotension, and restoration of end-organ perfusion; (4) avoidance and treatment of hypoglycemia; (5) cervical spine precautions; (6) treatment of intracranial hypertension; (7) treatment of seizures; (8) correction of electrolyte and acid-base abnormalities; and (9) avoidance of hyperthermia to prevent unnecessary increases in metabolic demand An emergent head CT scan is indicated for patients suspected to be at risk of herniation syndromes with initiation of acute intervention (e.g., midline head positioning; elevation of the head of the bed to 30 degrees; osmotic therapies, such as mannitol and/or hypertonic saline; sedation, neuromuscular blockade; and surgical decompression) as warranted to address increased ICP In addition to evaluation and treatment of confirmed seizures, prophylactic treatment with anticonvulsants during the first week after severe TBI is a widely accepted practice Prophylaxis may reduce the risk of posttraumatic seizures and improve outcomes.1 Additionally, broad-spectrum antibiotics for patients with suspected systemic or intracranial infection should be instituted empirically and should not be deferred if lumbar puncture cannot be safely performed Saltwater homeostasis may be dysregulated, resulting in the syndrome of inappropriate antidiuretic hormone secretion, central diabetes insipidus, or cerebral salt wasting (see Chapter 71), necessitating ongoing monitoring of fluid and electrolyte imbalances owing to risks of cerebral edema, pontine demyelination, and cardiac dysfunction.3 Nutritional support is also important to recovery Once a definitive diagnosis is obtained, additional specific therapy can be instituted Prognosis and Outcomes The outcome of coma largely depends on the underlying etiology In a study of 278 children with coma due to nontraumatic causes, mortality at year ranged from 3% to 84% Mortality depended on the etiology of coma, with accidental injuries (e.g., smoke inhalation, drowning) having the highest mortality and intoxications having the lowest.11 Neurologic and functional morbidity are also important consequences of coma There have been different scales developed to quantify such outcomes in children with coma Examples of these scales include the Glasgow Outcome Scale (GOS), Pediatric Cerebral Performance Category Scale, and Functional Status Scale These scales have been validated and are easy to apply The combination of physical signs, EEG, SSEPs, and MRI provides useful prognostic information and can help in predicting outcome Aspects of the physical examination that are considered predictive of outcome are pupillary reflex, presence of spontaneous respirations, and motor response to stimuli These findings are best evaluated at 24 hours after presentation, as absence of these signs on admission are not predictive of outcome.19,20 EEG can be useful in predicting outcome, although serial examinations are often needed Isoelectric, invariant low-amplitude, and burst– suppression patterns are associated with poor prognosis.21 Although not used frequently in the pediatric intensive care unit, SSEPs can be of value in prognosticating after brain injury In a study by Beca et al of 109 pediatric patients with coma, normal SSEPs had a positive predictive value for favorable outcome of 93%, and absent SSEPs had a positive predictive value for unfavorable outcome using the GOS of 92%.22 It is important to note that both the physical examination and EEG can be affected by sedatives, whereas SSEPs are not affected by these drugs However, SSEPs can be affected by a focal lesion (such as hemorrhage) interrupting conduction between the periphery and the somatosensory cortex Therefore, caution should be applied when interpreting negative responses in patients with a traumatic or structural abnormality.20,21 Lastly, MRI can be helpful in predicting outcome from coma Newer sequences—such as diffusionweighted imaging, susceptibility-weighted imaging, and MR spectroscopy—have been found to aid in prognostication of patients with hypoxic ischemic encephalopathy (HIE) and TBI.23–25 Abend and Licht24 suggested that waiting several days after injury to obtain an MRI provided better prognostic information in patients with HIE and that abnormalities in the cortex and basal ganglia or in the brainstem are predictive of poor outcome Providing prognostication regarding patients in coma is important to direct treatment or disposition and to help with discussions with families concerning goals of care, as a high probability of death without regaining consciousness may impact the decision to withdraw life-sustaining technologies However, if there is likelihood of some degree of neurologic recovery, discharge to an intensive acute care rehabilitation program is often pursued Ultimately, the decisions about what constitutes quality of life are determined by the patient’s family Physicians should provide accurate prognostication to the best of their abilities However, terms such as “good” versus “bad” outcome should be avoided, as this implies judgment regarding the quality of life Key References Abend NS, Licht DJ Predicting outcome in children with hypoxic ischemic encephalopathy Pediatr Crit Care Med 2008;9:32-39 Ashwal S Medical aspects of the minimally conscious state in children Brain Dev 2003;25(8):535-545 Bratton SL, Jardine DS, Morray JP Serial neurologic examinations after near drowning and outcome Arch Pediatr Adolesc Med 1994;148: 167-170 Kirkham FJ, Newton CR, Whitehouse W Paediatric coma scales Dev Med Child Neurol 2008;50:267-274 Mandel R, Martinot A, Delepoulle F, et al Prediction of outcome after hypoxic-ischemic encephalopathy: A prospective clinical and electrophysiologic study J Pediatr 2002;141:45-50 CHAPTER 62 Coma and Depressed Sensorium Michelson DJ, Ashwal S Evaluation of coma and brain death Semin Pediatr Neurol 2004;11(2):105-118 Posner JB, Saper CB, Schiff ND, et al The Diagnosis of Stupor and Coma 4th ed New York, NY: Oxford University Press; 2007 Sarnaik A, Bhaya N, Mahajan P Approach to a child with depressed level of consciousness and coma Therapy 2008;5(4): 435-449 767 Wong CP, Forsyth RJ, Kelly TP, Eyre JA Incidence, aetiology, and outcome of non-traumatic coma: a population based study Arch Dis Child 2001;84(3):193-199 Wong CP, Tay EL Childhood brain injury: a review Neurol Asia 2015; 20:105-115 The full reference list for this chapter is available at ExpertConsult.com e1 References Sarnaik A, Bhaya N, Mahajan P Approach to a child with depressed level of consciousness and coma Therapy 2008;5(4):435-449 Ashwal S Medical aspects of the minimally conscious state in children Brain Dev 2003;25(8):535-545 Michelson DJ, Ashwal S Evaluation of coma and brain death Semin Pediatr Neurol 2004;11(2):105-118 Kirkham FJ, Newton CR, Whitehouse W Paediatric coma scales Dev Med Child Neurol 2008;50:267-274 Teasdale G, Jennett B Assessment of coma and impaired consciousness A practical scale Lancet 1974;2:81-84 Murphy S, Thomas NJ, Gertz SJ, et al Tripartite stratification of the Glasgow Coma Scale in Children with Severe Traumatic Brain Injury and Mortality: an analysis from a Multi-Center Comparative Effectiveness Study J Neurotrauma 2017;34(14):2220–2229 James HE, Trauner DA The Glasgow Coma Scale In: James HE, Anas NG, Perkin RM, eds Brain Insults in Infants and Children: Pathophysiology and Management Orlando, FL: Grune and Stratton Inc.; 1985:179-182 Wong CP, Tay EL Childhood brain injury: a review Neurol Asia 2015;20:105-115 Mitra B, Cameron P, Butt W Population-based study of paediatric head injury J Paediatr Child Health 2007;43(3):154-159 10 Rutland-Brown W, Langlois JA, Thomas KE, Xi YL Incidence of traumatic brain injury in the United States, 2003 J Head Trauma Rehabil 2006;21(6):544-548 11 Wong CP, Forsyth RJ, Kelly TP, Eyre JA Incidence, aetiology, and outcome of non-traumatic coma: a population based study Arch Dis Child 2001;84(3):193-199 12 Fuller PM, Lu J Sleep and sleep states: hypothalamic regulation In: Squire LR, ed Encyclopedia of Neuroscience London: Academic Press; 2009:929-936 13 Posner JB, Saper CB, Schiff ND, et al The Diagnosis of Stupor and Coma 4th ed New York, NY: Oxford University Press; 2007 14 Schwartz RL, Roth T Neurophysiology of sleep and wakefulness: basic science and clinical implications Curr Neuropharmacol 2008; 6:367-378 15 Hakimi R, McDonagh DL Unconsciousness in the intensive care unit: a practical approach Int Anesthesiol Clin 2008;46:171-193 16 Salomone J, Pons P, McSwain N PHTLS: Pre-Hospital Trauma Support 6th ed St Louis: Mosby; 2007 17 Suttipongkaset P, Chaikittisilpa N, Vavilala MS, et al Blood pressure thresholds and mortality in pediatric traumatic brain injury Pediatrics 2018;142(2):e20180594 18 Agrawal S, Peters MJ, Adams GG, Pierce CM Prevalence of retinal hemorrhages in critically ill children Pediatrics 2012;129(6):e1388-e1396 19 Bratton SL, Jardine DS, Morray JP Serial neurologic examinations after near drowning and outcome Arch Pediatr Adolesc Med 1994; 148:167-170 20 Mandel R, Martinot A, Delepoulle F, et al Prediction of outcome after hypoxic-ischemic encephalopathy: a prospective clinical and electrophysiologic study J Pediatr 2002;141:45-50 21 Shewmon DA Coma prognosis in children Part II: clinical application J Clin Neurophysiol 2000;1:467-472 22 Beca J, Cox PN, Taylor MJ, et al Somatosensory evoked potentials for prediction of outcome in acute severe brain injury J Pediatr 1995;126:44-49 23 Galloway NR, Tong KA, Ashwal S, Oyoyo U, Obenaus A Diffusionweighted imaging improves outcome prediction in pediatric traumatic brain injury J Neurotrauma 2008;25:1153-1162 24 Abend NS, Licht DJ Predicting outcome in children with hypoxic ischemic encephalopathy Pediatr Crit Care Med 2008;9:32-39 25 Aaen GS, Holshouser BA, Sheridan C, et al Magnetic resonance spectroscopy predicts outcomes for children with nonaccidental trauma Pediatrics 2010;125:295-303 e2 Abstract: As a medical emergency, coma presents a challenge to intensivists because optimal care requires timely intervention in spite of often limited available patient history during the initial evaluation Assessment of level of consciousness and knowledge of central nervous system anatomy and physiology may guide interpretation of history and physical findings A careful general physical examination with a focused neurologic examination can suggest diagnosis, aid in location of lesions, guide therapeutic intervention, and determine prognosis Further adjunctive radiologic and laboratory evaluation can often confirm findings A time-sensitive, methodical approach to the management of the comatose child may affect prognosis and long-term outcomes Key Words: Coma, altered mental status, herniation, abnormal pupils, unconsciousness ... Child section, the major tenets of treatment must focus on (1) stabilization of airway; (2) breathing with adequate oxygenation and ventilation; (3) circulation with establishment of vascular... best of their abilities However, terms such as “good” versus “bad” outcome should be avoided, as this implies judgment regarding the quality of life Key References Abend NS, Licht DJ Predicting... Tay EL Childhood brain injury: a review Neurol Asia 2015; 20:105-115 The full reference list for this chapter is available at ExpertConsult.com e1 References Sarnaik A, Bhaya N, Mahajan P Approach