Long-term Outcome in Coma
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《美国医学杂志》
Departments of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Dhanvantri Nagar, Pondicherry, India
Abstract
Objective: To assess the relationship between Modified Glasgow Coma Scale, its components, brain stem reflexes and long term functional outcome in children with acute non-traumatic coma. Method: MGCS and brainstem reflexes were assessed at 6 hourly intervals for 72 hours from the time of admission. The children were followed up regularly and functional outcome was assessed at the end of 9 months. The lowest score of the MGCS and worst brain stem reflexes were used for the analysis. Results: Higher total MGCS score and verbal response score had a significant positive correlation with better functional outcome as measured by GOS and intelligence quotient. There was no association between the language function and the initial MGCS, its components and brain stem reflexes. Lower verbal response (P = 0.005) was the only factor that was found to be individually associated with poorer long term GOS score and intelligence quotient by multivariate linear regression analysis. Conclusion: In the long term prediction of outcome in acute non-traumatic coma, MGCS is not useful. However, verbal response, a component of MGCS, correlates well with long term functional outcome and intelligence quotient.
Keywords: Glasgow Coma Scale; Functional outcome; Glasgow outcome scale
Modified Glasgow Coma Scale (MGCS) is widely used for assessing the severity of pediatric coma.[1] In addition to this use, it has also been used to assess the long term outcome, which is of particular concern to the parents, medical personnel and other caretakers.[2],[3] Most of the currently available data on long term outcome is derived from traumatic coma, particularly adults, and has been extrapolated to use in pediatric non-traumatic coma. The present study was therefore conducted to evaluate the MGCS and its components with relation to long term functional outcome in survivors of acute non-traumatic coma in children.
Materials and Methods
This prospective observational study was conducted in the department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research, a tertiary care referral hospital in the Union Territory of Pondicherry, India from October 1998 to March 2000. All children between 5 and 12 years of age admitted with coma of less than 7 days duration were included in this study. Coma was defined as 'the unintentional failure of the patients to open their eyes spontaneously or in response to noise, inability to obey commands or localize painful stimulus with or without the ability to express comprehensible words or age appropriate language responses'.[4] Children with neurodevelopmental delay, any other preexisting neurological illness and those in whom the coma was secondary to trauma were excluded from the study. Standard predefined case definitions were used to identify the etiology of coma.[5] The subjects underwent focused neurological examination (MGCS and brain stem reflexes - oculocephalic, oculovestibular, pupillary reactivity) at 6 hourly intervals from the time of admission for a period of 72 hours. The lowest score of MGCS and worst brain stem reflexes score (summation of the number of elicitable reflexes) were used for analysis. In case of children who were intubated or who developed respiratory failure secondary to neurological etiology, the worst score before intubation/ respiratory failure was taken. Standard practice guidelines were used in the management of these children. The survivors were followed up every 3 months for a period of 9 months. Glasgow outcome scale (GOS) table1, intelligence quotient (assessed by Binet-Kamat Scale of intelligence) and language comprehension and expression (scored as no or a few incomprehensible words, impaired expression or comprehension, age appropriate normal language) were used for assessing the functional outcome. As GOS is a measure of acquired neurological disability it is essential that a certain level of baseline maturity and independent functioning is necessary. Hence in this only children of age 5 years and above were included. Data from standardized study forms were entered into a computer database for analysis using SPSS software. Spearman rank analysis was used to form the correlation matrix between the various clinical parameters to identify the significant relationships among them. Multivariate linear regression analysis was then performed to identify various factors, which individually affected the functional outcome.
Results
The study population comprised of 152 children with acute non-traumatic coma (75 boys, 77 girls) whose average age was 7 years 9 months. The MGCS was ￡ 8 in 91, between 9 and 12 in 56 and 313 in 5 children. Intracranial infection (viral encephalitis, pyogenic meningitis and tuberculous meningitis) was the most common cause of coma in this study (84.8%) with viral encephalitis (57.9%) forming the largest group table2. Among these children, 50 (32.8%) died and the rest (102) who survived were followed up. The mortality was the highest among the children with hepatic encephalopathy (50%) with next highest mortality in children with viral encephalitis (35.2%).
Ninety children completed the follow up period of 9 months. 73 children had a GOS score of 5 at the end of 9 months. Among the rest, 13 had a GOS score of 4 and 2 each had a GOS score of 3 and 2. Spearman rank analysis was performed to identify the association between age, sex, etiology, total MGCS score, score of the individual components and brain stem reflexes and long term functional outcome at 9 months expressed in terms of GOS, intelligence quotient and language individually. Among the Spearman's rho |R| values which were significant, the correlation coefficients relevant to the present study are given in Table 3. Higher total MGCS score and verbal response score had a significant positive correlation with better functional outcome as measured by GOS and Intelligence Quotient. There was no association between the language function and the initial MGCS, its components and brain stem reflexes table3. Multivariate linear regression analysis was then performed to identify the factors that independently predicted the long term outcome. Lower verbal response (P = 0.005) was the only factor that was found to be individually associated with poorer long term GOS score and Intelligence Quotient.
Discussion
The present study aimed at identifying the best suited parameter, among the commonly used measures for evaluating the severity of brain injury, which can be used to predict the long term functional outcome of children with non-traumatic coma. Since the sequelae of non-traumatic coma can be significant, the most important question in the minds of the parents and professionals is the prediction of functional outcome. It is a well known fact that prognosis in coma depends on its severity. When a child initially presents with acute non-traumatic brain injury, it is often impossible to ascertain the extent of the injury. The MGCS is routinely used in the acute care setting to assess the severity of brain injury clinically. Although the MGCS has been demonstrated to predict mortality both in traumatic and non-traumatic brain injury, only few studies are available studying its efficacy in prediction of functional outcome. [3],[6],[7],[8],[9]
The quantification of neurological morbidity can be particularly challenging in children. Various clinical tools have been in vogue for assessment of outcome following acute brain injury. The GOS, described by Teasdale, was one of the earliest scales used for outcome measurement following brain injury. Though various other scales like Rancho Los Amigos level of cognitive function scale, Rappaport's disability rating scale, Hoensbroeck disability scale for brain injury, functional status examination etc have been developed since the description of GOS, it has retained its utility as a valid rating scale for global outcome. However as GOS is a general measure and does not highlight important areas like Intelligence Quotient and language, these additional outcomes were evaluated independently in the present study.
Past studies have been shown that outcome is often dependant on etiology and severity of coma in pediatric non-traumatic coma.[10], [11],[12],[13] However, in the present study, the variables age, sex and etiology did not influence the long term outcome. Also total MGCS score did not correlate with long term outcome. However, verbal score, a component of MGCS was found to correlate with GOS score and Intelligence Quotient at 9 months after the acute insult. In spite of extensive literature search, we could not find a comparable study commenting on this aspect, though total MGCS score has been shown to be of value in identifying the poor long term outcome in traumatic coma.[14] It is interesting to note that none of the early measures of severity assessment is correlated with the language function.
Though many studies have found a statistically significant relationship between coma duration and motor outcome, the authors have not considered duration of coma in the analysis because some patients remain unresponsive even after the acute insult subsides and quantifying duration is inappropriate in these children.[15], [16]
Conclusion
In the long term prediction of outcome in acute non-traumatic coma, MGCS is not useful. However, verbal response, a component of MGCS, correlates well with long term functional outcome and Intelligence Quotient.
References
1. Reilly P, Simpson D, Sprod R et al. Assessing the conscious level in infants and young children: a pediatric version of Glasgow Coma Scale. Child Nerv Syst 1988; 4: 30-33.
2. Barlow P, Teasdale G. Prediction of outcome and the management of severe head injuries: The attitudes of neurosurgeons. Neurosurgery 1986; 19: 989-991.
3. Johnston RB, Mellits DE. Pediatric coma: Prognosis and outcome. Develop Med Child Neurol 1980; 23: 3 - 12
4. Awasthi S, Moin S, Iyer SM et al. Modified Glasgow Coma Scale to predict mortality in children with acute infections of the central nervous system. Nat Med J Ind 1997; 10: 214-216.
5. Nayana Prabha PC, Nalini P, Serane VT. Role of Glasgow Coma Scale in Pediatric Non-traumatic Coma. Indian Pediatr 2003; 40 : 620-625.
6. Jennett WB, Teasdale GM, Braakman R et al. Predicting outcome in individual patients after severe head injury. Lancet 1976; 2: 1031-1034.
7. Fleming J, Tooth L, Hassell M et al. Prediction of community integration and vocational outcome 2-5 years after traumatic brain injury rehabilitation in Australia. Brain Inj 1999; 13 : 417-431.
8. Sacco RL, Van Gool R, Mohr JP, Hauser WA. Non-traumatic coma. Glasgow Coma Score and coma etiology as prediction of 2 week outcome. Arch Neurol 1994; 47: 1181-1184.
9. Zafonte R, Hammond FM, Mann NR et al. Relationship between Glasgow coma scale and functional outcome. Am J Phys Med Rehabil 1996; 75: 364-369.
10. Dean JM, Kaufman ND. Prognostic indicators in pediatric near drowning: the Glasgow coma scale. Crit Care Med 1981; 9:536-9.
11. Grimwood K, Nolan TM, Bond L et al. Risk factors for adverse outcomes of bacterial meningitis. J Paediatr Child Health 1996;32 : 457-462.
12. Van Hensbroek MB, Palmer A, Jaffar S et al. Residual neurologic sequelae after childhood cerebral malaria. J Pediatr 1997; 131 : 125-129.
13. Bhutto E, Naim M, Ehtesham M et al. Prognostic indicators of childhood acute viral encephalitis. J Pakistan Med Assos 1999; 49 : 311-316.
14. Signorini DF, Andrews PJ, Jones PA et al. Predicting survival using simple clinical variables: a case study in traumatic brain injury. J Neurol Neurosurg Psychiatry 1999; 66 : 20-25.
15. Johnston B, Seshia SS. Predictors of outcome in non-traumatic coma in childhood. Acta Neurol Scand 1984; 69 : 417-427
16. Heiskanen O, Kaste M. Late prognosis in severe brain injury in children. Develop Med Child Neurol 1974; 16 : 11-14.(Nayana Prabha P, Serane T)
Abstract
Objective: To assess the relationship between Modified Glasgow Coma Scale, its components, brain stem reflexes and long term functional outcome in children with acute non-traumatic coma. Method: MGCS and brainstem reflexes were assessed at 6 hourly intervals for 72 hours from the time of admission. The children were followed up regularly and functional outcome was assessed at the end of 9 months. The lowest score of the MGCS and worst brain stem reflexes were used for the analysis. Results: Higher total MGCS score and verbal response score had a significant positive correlation with better functional outcome as measured by GOS and intelligence quotient. There was no association between the language function and the initial MGCS, its components and brain stem reflexes. Lower verbal response (P = 0.005) was the only factor that was found to be individually associated with poorer long term GOS score and intelligence quotient by multivariate linear regression analysis. Conclusion: In the long term prediction of outcome in acute non-traumatic coma, MGCS is not useful. However, verbal response, a component of MGCS, correlates well with long term functional outcome and intelligence quotient.
Keywords: Glasgow Coma Scale; Functional outcome; Glasgow outcome scale
Modified Glasgow Coma Scale (MGCS) is widely used for assessing the severity of pediatric coma.[1] In addition to this use, it has also been used to assess the long term outcome, which is of particular concern to the parents, medical personnel and other caretakers.[2],[3] Most of the currently available data on long term outcome is derived from traumatic coma, particularly adults, and has been extrapolated to use in pediatric non-traumatic coma. The present study was therefore conducted to evaluate the MGCS and its components with relation to long term functional outcome in survivors of acute non-traumatic coma in children.
Materials and Methods
This prospective observational study was conducted in the department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research, a tertiary care referral hospital in the Union Territory of Pondicherry, India from October 1998 to March 2000. All children between 5 and 12 years of age admitted with coma of less than 7 days duration were included in this study. Coma was defined as 'the unintentional failure of the patients to open their eyes spontaneously or in response to noise, inability to obey commands or localize painful stimulus with or without the ability to express comprehensible words or age appropriate language responses'.[4] Children with neurodevelopmental delay, any other preexisting neurological illness and those in whom the coma was secondary to trauma were excluded from the study. Standard predefined case definitions were used to identify the etiology of coma.[5] The subjects underwent focused neurological examination (MGCS and brain stem reflexes - oculocephalic, oculovestibular, pupillary reactivity) at 6 hourly intervals from the time of admission for a period of 72 hours. The lowest score of MGCS and worst brain stem reflexes score (summation of the number of elicitable reflexes) were used for analysis. In case of children who were intubated or who developed respiratory failure secondary to neurological etiology, the worst score before intubation/ respiratory failure was taken. Standard practice guidelines were used in the management of these children. The survivors were followed up every 3 months for a period of 9 months. Glasgow outcome scale (GOS) table1, intelligence quotient (assessed by Binet-Kamat Scale of intelligence) and language comprehension and expression (scored as no or a few incomprehensible words, impaired expression or comprehension, age appropriate normal language) were used for assessing the functional outcome. As GOS is a measure of acquired neurological disability it is essential that a certain level of baseline maturity and independent functioning is necessary. Hence in this only children of age 5 years and above were included. Data from standardized study forms were entered into a computer database for analysis using SPSS software. Spearman rank analysis was used to form the correlation matrix between the various clinical parameters to identify the significant relationships among them. Multivariate linear regression analysis was then performed to identify various factors, which individually affected the functional outcome.
Results
The study population comprised of 152 children with acute non-traumatic coma (75 boys, 77 girls) whose average age was 7 years 9 months. The MGCS was ￡ 8 in 91, between 9 and 12 in 56 and 313 in 5 children. Intracranial infection (viral encephalitis, pyogenic meningitis and tuberculous meningitis) was the most common cause of coma in this study (84.8%) with viral encephalitis (57.9%) forming the largest group table2. Among these children, 50 (32.8%) died and the rest (102) who survived were followed up. The mortality was the highest among the children with hepatic encephalopathy (50%) with next highest mortality in children with viral encephalitis (35.2%).
Ninety children completed the follow up period of 9 months. 73 children had a GOS score of 5 at the end of 9 months. Among the rest, 13 had a GOS score of 4 and 2 each had a GOS score of 3 and 2. Spearman rank analysis was performed to identify the association between age, sex, etiology, total MGCS score, score of the individual components and brain stem reflexes and long term functional outcome at 9 months expressed in terms of GOS, intelligence quotient and language individually. Among the Spearman's rho |R| values which were significant, the correlation coefficients relevant to the present study are given in Table 3. Higher total MGCS score and verbal response score had a significant positive correlation with better functional outcome as measured by GOS and Intelligence Quotient. There was no association between the language function and the initial MGCS, its components and brain stem reflexes table3. Multivariate linear regression analysis was then performed to identify the factors that independently predicted the long term outcome. Lower verbal response (P = 0.005) was the only factor that was found to be individually associated with poorer long term GOS score and Intelligence Quotient.
Discussion
The present study aimed at identifying the best suited parameter, among the commonly used measures for evaluating the severity of brain injury, which can be used to predict the long term functional outcome of children with non-traumatic coma. Since the sequelae of non-traumatic coma can be significant, the most important question in the minds of the parents and professionals is the prediction of functional outcome. It is a well known fact that prognosis in coma depends on its severity. When a child initially presents with acute non-traumatic brain injury, it is often impossible to ascertain the extent of the injury. The MGCS is routinely used in the acute care setting to assess the severity of brain injury clinically. Although the MGCS has been demonstrated to predict mortality both in traumatic and non-traumatic brain injury, only few studies are available studying its efficacy in prediction of functional outcome. [3],[6],[7],[8],[9]
The quantification of neurological morbidity can be particularly challenging in children. Various clinical tools have been in vogue for assessment of outcome following acute brain injury. The GOS, described by Teasdale, was one of the earliest scales used for outcome measurement following brain injury. Though various other scales like Rancho Los Amigos level of cognitive function scale, Rappaport's disability rating scale, Hoensbroeck disability scale for brain injury, functional status examination etc have been developed since the description of GOS, it has retained its utility as a valid rating scale for global outcome. However as GOS is a general measure and does not highlight important areas like Intelligence Quotient and language, these additional outcomes were evaluated independently in the present study.
Past studies have been shown that outcome is often dependant on etiology and severity of coma in pediatric non-traumatic coma.[10], [11],[12],[13] However, in the present study, the variables age, sex and etiology did not influence the long term outcome. Also total MGCS score did not correlate with long term outcome. However, verbal score, a component of MGCS was found to correlate with GOS score and Intelligence Quotient at 9 months after the acute insult. In spite of extensive literature search, we could not find a comparable study commenting on this aspect, though total MGCS score has been shown to be of value in identifying the poor long term outcome in traumatic coma.[14] It is interesting to note that none of the early measures of severity assessment is correlated with the language function.
Though many studies have found a statistically significant relationship between coma duration and motor outcome, the authors have not considered duration of coma in the analysis because some patients remain unresponsive even after the acute insult subsides and quantifying duration is inappropriate in these children.[15], [16]
Conclusion
In the long term prediction of outcome in acute non-traumatic coma, MGCS is not useful. However, verbal response, a component of MGCS, correlates well with long term functional outcome and Intelligence Quotient.
References
1. Reilly P, Simpson D, Sprod R et al. Assessing the conscious level in infants and young children: a pediatric version of Glasgow Coma Scale. Child Nerv Syst 1988; 4: 30-33.
2. Barlow P, Teasdale G. Prediction of outcome and the management of severe head injuries: The attitudes of neurosurgeons. Neurosurgery 1986; 19: 989-991.
3. Johnston RB, Mellits DE. Pediatric coma: Prognosis and outcome. Develop Med Child Neurol 1980; 23: 3 - 12
4. Awasthi S, Moin S, Iyer SM et al. Modified Glasgow Coma Scale to predict mortality in children with acute infections of the central nervous system. Nat Med J Ind 1997; 10: 214-216.
5. Nayana Prabha PC, Nalini P, Serane VT. Role of Glasgow Coma Scale in Pediatric Non-traumatic Coma. Indian Pediatr 2003; 40 : 620-625.
6. Jennett WB, Teasdale GM, Braakman R et al. Predicting outcome in individual patients after severe head injury. Lancet 1976; 2: 1031-1034.
7. Fleming J, Tooth L, Hassell M et al. Prediction of community integration and vocational outcome 2-5 years after traumatic brain injury rehabilitation in Australia. Brain Inj 1999; 13 : 417-431.
8. Sacco RL, Van Gool R, Mohr JP, Hauser WA. Non-traumatic coma. Glasgow Coma Score and coma etiology as prediction of 2 week outcome. Arch Neurol 1994; 47: 1181-1184.
9. Zafonte R, Hammond FM, Mann NR et al. Relationship between Glasgow coma scale and functional outcome. Am J Phys Med Rehabil 1996; 75: 364-369.
10. Dean JM, Kaufman ND. Prognostic indicators in pediatric near drowning: the Glasgow coma scale. Crit Care Med 1981; 9:536-9.
11. Grimwood K, Nolan TM, Bond L et al. Risk factors for adverse outcomes of bacterial meningitis. J Paediatr Child Health 1996;32 : 457-462.
12. Van Hensbroek MB, Palmer A, Jaffar S et al. Residual neurologic sequelae after childhood cerebral malaria. J Pediatr 1997; 131 : 125-129.
13. Bhutto E, Naim M, Ehtesham M et al. Prognostic indicators of childhood acute viral encephalitis. J Pakistan Med Assos 1999; 49 : 311-316.
14. Signorini DF, Andrews PJ, Jones PA et al. Predicting survival using simple clinical variables: a case study in traumatic brain injury. J Neurol Neurosurg Psychiatry 1999; 66 : 20-25.
15. Johnston B, Seshia SS. Predictors of outcome in non-traumatic coma in childhood. Acta Neurol Scand 1984; 69 : 417-427
16. Heiskanen O, Kaste M. Late prognosis in severe brain injury in children. Develop Med Child Neurol 1974; 16 : 11-14.(Nayana Prabha P, Serane T)