Br.J. Anaesth. (1976), 48, 761
ASSESSMENT OF HEAD INJURIES G. TEASDALE
Downloaded from http://bja.oxfordjournals.org/ at University of Birmingham on June 8, 2015
features occurs in only a minority of patients (Jamieson and Yelland, 1968). Subdural and intracerebral haematomas are usually complications of significant immediate impact damage and supervene upon impairment of consciousness from the time of injury. Oedema is found in the white matter adjacent to BRAIN DAMAGE AFTER HEAD INJURY contusions and haematomas. Diffuse oedema, with Brain damage may be primary or may manifest as a swelling of both hemispheres, is a rare event and secondary delayed event. Either may affect the brain has a predilection for children, often after initially locally or diffusely. apparently trivial injuries. Brain abscess or meningitis complicates compound Primary impact damage depressed skull fractures, or fractures of the base This results mainly from acceleration/deceleration involving the paranasal sinuses. Clinically evident forces transmitted to the brain as a whole. Macrocerebrospinal fluid leak is not a prerequisite. scopically, the most prominent features are the Brain shift and increased intracranial pressure are presence of contusions of the cerebral cortex, either underlying the site of impact (coup) or on the under- consequences of many of the processes occurring surfaces of the frontal lobes and the tips of the after head injury. Shift and herniation result in local temporal lobes as a result of contra-coup impact. Of compression of the brain against the dural partitions greater neurological significance are the microscopic within the intracranial cavity; in particular the lesions which affect nerve fibres in the sub-cortical cerebral peduncle, oculomotor nerve and temporal white matter, in the long tracts in the brain stem and lobe may be compressed against the edge of the in the reticular activating system. These lesions are tentorium cerebelli. Ischaemic brain damage, in a almost invariably present in many parts of the brain pattern suggesting global reduction in cerebral blood in severely injured patients. The concept of a primary flow, is found in up to 60% of fatal head injuries injury limited to, or mainly within, the brain stem has (Jennett et al., 1973; Adams, 1975). In addition to been largely dismissed (Mitchell and Adams, 1973). impaired cerebral perfusion from increased intracranial pressure, systemic hypotension may be a major The severity of initial unconsciousness and cause of ischaemia in certain patients. neurological deficit reflects the extent of impact The twin aims in patient management are to ensure damage. Injuries resulting in prolonged unconsciousfavourable circumstances for the recovery from ness differ from mild concussive injuries only in primary brain damage and to anticipate secondary quantity, rather than kind. complications, the so-called second accident. Ideally, the latter should be prevented, but it is usually more Secondary damage Processes such as haemorrhage, oedema and feasible to minimize secondary damage by the early infection can interfere with recovery from initial recognition and treatment of complications. damage or may develop in injuries which initially DIAGNOSIS OF HEAD INJURY were not severe. Extradural haemorrhage in adults is almost always Sometimes a clear story is not available when a patient a complication of skull fracture. The classic lucid is admitted in coma. Scalp trauma increases the interval between injury and development of clinical possibility of head injury, but sometimes the primary condition may have been a cerebrovascular accident, GRAHAM TEASDALE, M.B., B.S., M.R.C.P., F.R.C.S.(EDIN.), an epileptic fit, or the ingestion of alcohol or drugs. University Department of Neurosurgery, Institute of Neurological Sciences, Southern General Hospital, Glasgow The story should be pieced together as well as possible from all sources of information—ambulance men, G51 4TF. Most of the 100,000 patients admitted to hospital every year in Britain following head injury prove to have mild injuries, 75% being discharged within 48 h. Anaesthetists are involved in the management of only the more severely injured patients, in particular those with brain damage and depressed consciousness.
762
BRITISH JOURNAL OF ANAESTHESIA
police and relatives. However, 10% of patients with traumatic intracranial lesions are initially diagnosed as having had a cerebrovascular accident (Galbraith, 1976). If there is scalp trauma and skull x-rays disclose a fracture, it is probable that a head injury has been the primary event and that the hemiplegia signifies an intracranial haematoma. Where alcohol is a complicating factor, blood concentrations may be useful; those below 200mg/100ml are rarely the cause of impairment of consciousness in patients with head injuries (Galbraith et al., 1976). Biochemical analysis should exclude metabolic reasons for unconsciousness.
Assessment of conscious level
In spite of the importance of assessing impaired consciousness most existings systems have defects. Some depend upon specific anatomical-clinical correlations, which do not exist in practice. Some describe coma by a series of arbitrary steps, when in reality there are no clear watersheds in the continuous spectrum of responsiveness exhibited by patients. Few have been tested for the consistency with which they can be applied by different observers. As the management of severely injured patients depends upon observations made by junior medical and by nursing staff, to be of practical value a system must be simple and based upon clearly denned criteria. The Glasgow Coma Scale (Teasdale and Jennett, 1974) was developed taking account of these considerations. Three separate aspects of the patient's responsiveness are evaluated: the stimulus required to induce eye opening; the best verbal response; and the best motor response. Each is described according to a well-defined series of responses which indicate increasing degrees of dysfunction. Eye opening. Spontaneous opening indicates that arousal mechanisms in the brain stem are active. It does not necessarily imply awareness. If spontaneous opening is not present verbal command is followed by painful stimulation, applied by pressure on the fingertips.
The use of three separate responses avoids the need to make arbitrary distinctions between consciousness and different levels of coma, and does not entail assumptions of specific underlying anatomical lesions. The reliability of the scale in the hands of a wide range of observers has been confirmed (Teasdale, Knill-Jones and Jennett, 1974). In our experience the introduction of the scale has greatly enhanced the value of routine observations (Teasdale, 1975). A chart on which the responses are recorded provides a visual profile of the patient's progress which can be rapidly assessed (fig. 1) (Teasdale, Galbraith and Clarke, 1975). Many institutions in America and Europe have adopted the scale and found it an improvement on previous methods. Assessment of focal neurological signs
Assessment is directed first to determine whether there is evidence of a lesion on one side of the brain, and second towards detecting evidence of
Downloaded from http://bja.oxfordjournals.org/ at University of Birmingham on June 8, 2015
ASSESSMENT OF IMPAIRED BRAIN FUNCTION
Clinical monitoring of conscious level and focal neurological features is the foundation of the management of these patients. In patients treated electively by artificial ventilation, the clinical features usually relied upon to judge progress are lost. It is better to avoid, at least in the first 24-48 h after injury, the use of drugs and procedures which may make it difficult to assess the patient's clinical state.
Once the patient has been roused as fully as possible, speech and motor performance are assessed. Verbal response. Orientation requires the patient to know who he is, where he is and the date. Conversational exchange short of this is termed confused. Inappropriate words refer to intelligible articulation used in an exclamatory, random way. Moaning and groaning constitute incomprehensible sounds. While the presence of speech indicates a high degree of integration in the nervous system, speechlessness may, of course, be the result of reasons other than impaired consciousness such as dysphasia. Best motor response. To reflect the functional state of the brain as a whole, the best or highest response from any limb is recorded. Differences between the response of the two sides indicate focal brain damage. Obeying commands is judged from the response to instructions such as to lift the arm, or protrude the tongue. Reflex grasp responses occur in unconscious patients and asking a patient to squeeze the examiner's fingers is not a reliable test. Painful stimulation is applied in a standard way, fingertip pressure being used initially to induce a response, followed by pressure over the supraorbital notch to test for localization. Flexion responses may vary between normal rapid withdrawal and abnormal slow dystonic movements in which the limbs assume stereotyped postures. Experienced observers may distinguish the various types but generally this separation cannot be made consistently. Extension responses of the upper or lower limbs are clearly abnormal.
ASSESSMENT OF HEAD INJURIES
763
INSTITUTE OF NEUROLOGICAL SCIENCES. GLASGOW OBSERVATION CHART NAri/IE REC ORD No.
29 OCT
28 OCT
27 OCT
26 OCT
30 OCT
TIME
n 0
Eyes open
A
Orientated
C
L E
-•--•
1
, » •
Incomprehensible
•-
. « .
-#.
a
-•--•- -•-
• • -
«..
-•-
i
-•- V
Localise pain _
Flexion to pain Extension to pain
I--
J
V
Inappropriate
Obey commands Best motor response
V -».
• • -
\
Confused
None
A
A,
•-
V
-•-
• » -• 1 1
1
•--©-
Eyes closed by swelling =r C
Endotracheal tube or tracheostomy = T
Usually record the best arm response
1 FIG. 1. Chart illustrating use of Glasgow Coma Scale. (Reproduced by kind permission of the None
Journal of the Royal College of Physicians.)
improvement or deterioration. In the presence of impaired consciousness, classical neurological signs are difficult to elicit and the findings may be at variance with conventional teaching. Detailed accounts of the examination of unconscious patients are given by Fisher (1969) and Plum and Posner (1972). The detection of lateralizing features and their evolution is more important than niceties of localization. Signs of supratentorial damage
Hemianopia may be detected by the absence of blinking when a patient is threatened from one side. This distinction is often somewhat unreliable and subjective. Unilateral facial weakness is indicated by a cheek blowing out during respiration or by lack of contraction in response to a painful stimulus. Deviation of the eyes towards the affected side of the brain occurs with frontal lesions. During an epileptic fit, on the contrary, the eyes are deviated away from the side of the irritative focus. Unilateral pontine lesions also cause contralateral conjugate eye deviation. Hemiparesis. When trying to detect focal weakness, the emphasis is upon the function of the worst side. Paucity of spontaneous movement on one side may provide the first clue. If both arms are held upright and then released, hypotonia and paresis are shown by the more rapid collapse of the affected limb. Reflex asymmetry alone is rarely helpful. Asymmetrical response to painful stimulation is a useful test, as when a patient preferentially localizes stimulation
with one side. With more severe brain lesions, and abnormal flexion or extension posturing, asymmetry may still be detected, for example abnormal flexion on one side and extension on the other. A posture of flexion in the upper limbs with extension in the lower is often termed "decorticate", while "decerebrate" posturing refers to internal rotation and extension of the arms. In neither case does the anatomical assumption underlying the term justify its use and many patients fluctuate between the two postures, either in response to varying stimulation at the same examination or at different times after injury. Signs of brain stem damage
Examination of the size and reactivity of the pupils reflects the integrity of the upper brain stem. With an expanding supratentorial lesion, hypothalamic dysfunction may initially produce small pupils. With herniation and involvement of one side of the midbrain and third nerve, the pupil on the same side as the mass becomes dilated and non-reactive. Light shone in that eye gives consensual constriction of the opposite pupil, distinguishing a third nerve lesion from an optic nerve injury. The pathways subserving eye movements traverse both the mid-brain and the pons (fig. 2). If the patient is too drowsy to carry out voluntary eye movements, vestibulo-ocular reflexes can be utilized. The doll's eyes phenomenon is a response to rapid rotation of the
Downloaded from http://bja.oxfordjournals.org/ at University of Birmingham on June 8, 2015
Best verbal response
V
To pain None
f- _•
•*,
To speech
M
S
••
Spontaneously
C
DATE
764
BRITISH JOURNAL OF ANAESTHESIA CALORIC RESPONSES
Nystagmus
ASSESSMENT OF HEAD INJURIES G. TEASDALE
Downloaded from http://bja.oxfordjournals.org/ at University of Birmingham on June 8, 2015
features occurs in only a minority of patients (Jamieson and Yelland, 1968). Subdural and intracerebral haematomas are usually complications of significant immediate impact damage and supervene upon impairment of consciousness from the time of injury. Oedema is found in the white matter adjacent to BRAIN DAMAGE AFTER HEAD INJURY contusions and haematomas. Diffuse oedema, with Brain damage may be primary or may manifest as a swelling of both hemispheres, is a rare event and secondary delayed event. Either may affect the brain has a predilection for children, often after initially locally or diffusely. apparently trivial injuries. Brain abscess or meningitis complicates compound Primary impact damage depressed skull fractures, or fractures of the base This results mainly from acceleration/deceleration involving the paranasal sinuses. Clinically evident forces transmitted to the brain as a whole. Macrocerebrospinal fluid leak is not a prerequisite. scopically, the most prominent features are the Brain shift and increased intracranial pressure are presence of contusions of the cerebral cortex, either underlying the site of impact (coup) or on the under- consequences of many of the processes occurring surfaces of the frontal lobes and the tips of the after head injury. Shift and herniation result in local temporal lobes as a result of contra-coup impact. Of compression of the brain against the dural partitions greater neurological significance are the microscopic within the intracranial cavity; in particular the lesions which affect nerve fibres in the sub-cortical cerebral peduncle, oculomotor nerve and temporal white matter, in the long tracts in the brain stem and lobe may be compressed against the edge of the in the reticular activating system. These lesions are tentorium cerebelli. Ischaemic brain damage, in a almost invariably present in many parts of the brain pattern suggesting global reduction in cerebral blood in severely injured patients. The concept of a primary flow, is found in up to 60% of fatal head injuries injury limited to, or mainly within, the brain stem has (Jennett et al., 1973; Adams, 1975). In addition to been largely dismissed (Mitchell and Adams, 1973). impaired cerebral perfusion from increased intracranial pressure, systemic hypotension may be a major The severity of initial unconsciousness and cause of ischaemia in certain patients. neurological deficit reflects the extent of impact The twin aims in patient management are to ensure damage. Injuries resulting in prolonged unconsciousfavourable circumstances for the recovery from ness differ from mild concussive injuries only in primary brain damage and to anticipate secondary quantity, rather than kind. complications, the so-called second accident. Ideally, the latter should be prevented, but it is usually more Secondary damage Processes such as haemorrhage, oedema and feasible to minimize secondary damage by the early infection can interfere with recovery from initial recognition and treatment of complications. damage or may develop in injuries which initially DIAGNOSIS OF HEAD INJURY were not severe. Extradural haemorrhage in adults is almost always Sometimes a clear story is not available when a patient a complication of skull fracture. The classic lucid is admitted in coma. Scalp trauma increases the interval between injury and development of clinical possibility of head injury, but sometimes the primary condition may have been a cerebrovascular accident, GRAHAM TEASDALE, M.B., B.S., M.R.C.P., F.R.C.S.(EDIN.), an epileptic fit, or the ingestion of alcohol or drugs. University Department of Neurosurgery, Institute of Neurological Sciences, Southern General Hospital, Glasgow The story should be pieced together as well as possible from all sources of information—ambulance men, G51 4TF. Most of the 100,000 patients admitted to hospital every year in Britain following head injury prove to have mild injuries, 75% being discharged within 48 h. Anaesthetists are involved in the management of only the more severely injured patients, in particular those with brain damage and depressed consciousness.
762
BRITISH JOURNAL OF ANAESTHESIA
police and relatives. However, 10% of patients with traumatic intracranial lesions are initially diagnosed as having had a cerebrovascular accident (Galbraith, 1976). If there is scalp trauma and skull x-rays disclose a fracture, it is probable that a head injury has been the primary event and that the hemiplegia signifies an intracranial haematoma. Where alcohol is a complicating factor, blood concentrations may be useful; those below 200mg/100ml are rarely the cause of impairment of consciousness in patients with head injuries (Galbraith et al., 1976). Biochemical analysis should exclude metabolic reasons for unconsciousness.
Assessment of conscious level
In spite of the importance of assessing impaired consciousness most existings systems have defects. Some depend upon specific anatomical-clinical correlations, which do not exist in practice. Some describe coma by a series of arbitrary steps, when in reality there are no clear watersheds in the continuous spectrum of responsiveness exhibited by patients. Few have been tested for the consistency with which they can be applied by different observers. As the management of severely injured patients depends upon observations made by junior medical and by nursing staff, to be of practical value a system must be simple and based upon clearly denned criteria. The Glasgow Coma Scale (Teasdale and Jennett, 1974) was developed taking account of these considerations. Three separate aspects of the patient's responsiveness are evaluated: the stimulus required to induce eye opening; the best verbal response; and the best motor response. Each is described according to a well-defined series of responses which indicate increasing degrees of dysfunction. Eye opening. Spontaneous opening indicates that arousal mechanisms in the brain stem are active. It does not necessarily imply awareness. If spontaneous opening is not present verbal command is followed by painful stimulation, applied by pressure on the fingertips.
The use of three separate responses avoids the need to make arbitrary distinctions between consciousness and different levels of coma, and does not entail assumptions of specific underlying anatomical lesions. The reliability of the scale in the hands of a wide range of observers has been confirmed (Teasdale, Knill-Jones and Jennett, 1974). In our experience the introduction of the scale has greatly enhanced the value of routine observations (Teasdale, 1975). A chart on which the responses are recorded provides a visual profile of the patient's progress which can be rapidly assessed (fig. 1) (Teasdale, Galbraith and Clarke, 1975). Many institutions in America and Europe have adopted the scale and found it an improvement on previous methods. Assessment of focal neurological signs
Assessment is directed first to determine whether there is evidence of a lesion on one side of the brain, and second towards detecting evidence of
Downloaded from http://bja.oxfordjournals.org/ at University of Birmingham on June 8, 2015
ASSESSMENT OF IMPAIRED BRAIN FUNCTION
Clinical monitoring of conscious level and focal neurological features is the foundation of the management of these patients. In patients treated electively by artificial ventilation, the clinical features usually relied upon to judge progress are lost. It is better to avoid, at least in the first 24-48 h after injury, the use of drugs and procedures which may make it difficult to assess the patient's clinical state.
Once the patient has been roused as fully as possible, speech and motor performance are assessed. Verbal response. Orientation requires the patient to know who he is, where he is and the date. Conversational exchange short of this is termed confused. Inappropriate words refer to intelligible articulation used in an exclamatory, random way. Moaning and groaning constitute incomprehensible sounds. While the presence of speech indicates a high degree of integration in the nervous system, speechlessness may, of course, be the result of reasons other than impaired consciousness such as dysphasia. Best motor response. To reflect the functional state of the brain as a whole, the best or highest response from any limb is recorded. Differences between the response of the two sides indicate focal brain damage. Obeying commands is judged from the response to instructions such as to lift the arm, or protrude the tongue. Reflex grasp responses occur in unconscious patients and asking a patient to squeeze the examiner's fingers is not a reliable test. Painful stimulation is applied in a standard way, fingertip pressure being used initially to induce a response, followed by pressure over the supraorbital notch to test for localization. Flexion responses may vary between normal rapid withdrawal and abnormal slow dystonic movements in which the limbs assume stereotyped postures. Experienced observers may distinguish the various types but generally this separation cannot be made consistently. Extension responses of the upper or lower limbs are clearly abnormal.
ASSESSMENT OF HEAD INJURIES
763
INSTITUTE OF NEUROLOGICAL SCIENCES. GLASGOW OBSERVATION CHART NAri/IE REC ORD No.
29 OCT
28 OCT
27 OCT
26 OCT
30 OCT
TIME
n 0
Eyes open
A
Orientated
C
L E
-•--•
1
, » •
Incomprehensible
•-
. « .
-#.
a
-•--•- -•-
• • -
«..
-•-
i
-•- V
Localise pain _
Flexion to pain Extension to pain
I--
J
V
Inappropriate
Obey commands Best motor response
V -».
• • -
\
Confused
None
A
A,
•-
V
-•-
• » -• 1 1
1
•--©-
Eyes closed by swelling =r C
Endotracheal tube or tracheostomy = T
Usually record the best arm response
1 FIG. 1. Chart illustrating use of Glasgow Coma Scale. (Reproduced by kind permission of the None
Journal of the Royal College of Physicians.)
improvement or deterioration. In the presence of impaired consciousness, classical neurological signs are difficult to elicit and the findings may be at variance with conventional teaching. Detailed accounts of the examination of unconscious patients are given by Fisher (1969) and Plum and Posner (1972). The detection of lateralizing features and their evolution is more important than niceties of localization. Signs of supratentorial damage
Hemianopia may be detected by the absence of blinking when a patient is threatened from one side. This distinction is often somewhat unreliable and subjective. Unilateral facial weakness is indicated by a cheek blowing out during respiration or by lack of contraction in response to a painful stimulus. Deviation of the eyes towards the affected side of the brain occurs with frontal lesions. During an epileptic fit, on the contrary, the eyes are deviated away from the side of the irritative focus. Unilateral pontine lesions also cause contralateral conjugate eye deviation. Hemiparesis. When trying to detect focal weakness, the emphasis is upon the function of the worst side. Paucity of spontaneous movement on one side may provide the first clue. If both arms are held upright and then released, hypotonia and paresis are shown by the more rapid collapse of the affected limb. Reflex asymmetry alone is rarely helpful. Asymmetrical response to painful stimulation is a useful test, as when a patient preferentially localizes stimulation
with one side. With more severe brain lesions, and abnormal flexion or extension posturing, asymmetry may still be detected, for example abnormal flexion on one side and extension on the other. A posture of flexion in the upper limbs with extension in the lower is often termed "decorticate", while "decerebrate" posturing refers to internal rotation and extension of the arms. In neither case does the anatomical assumption underlying the term justify its use and many patients fluctuate between the two postures, either in response to varying stimulation at the same examination or at different times after injury. Signs of brain stem damage
Examination of the size and reactivity of the pupils reflects the integrity of the upper brain stem. With an expanding supratentorial lesion, hypothalamic dysfunction may initially produce small pupils. With herniation and involvement of one side of the midbrain and third nerve, the pupil on the same side as the mass becomes dilated and non-reactive. Light shone in that eye gives consensual constriction of the opposite pupil, distinguishing a third nerve lesion from an optic nerve injury. The pathways subserving eye movements traverse both the mid-brain and the pons (fig. 2). If the patient is too drowsy to carry out voluntary eye movements, vestibulo-ocular reflexes can be utilized. The doll's eyes phenomenon is a response to rapid rotation of the
Downloaded from http://bja.oxfordjournals.org/ at University of Birmingham on June 8, 2015
Best verbal response
V
To pain None
f- _•
•*,
To speech
M
S
••
Spontaneously
C
DATE
764
BRITISH JOURNAL OF ANAESTHESIA CALORIC RESPONSES
Nystagmus
