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Postconcussion syndrome following mild head injury: how significant when it is work-related?
Journal of Clinical Neuroscience (1998) 5(4), 399~401 © Harcourt Brace & Co. Ltd 1998
Clinical studies
Postconcussion syndrome following mild head injury: how significant w h e n it is w o r k - r e l a t e d ? John N. K. Hsiang I MD PhD, Wai S. Poon 1 MBChB FRCS(Glasgow),A s h l e y L. M. Yu 2 MSc ~Division of Neurosurgery and 2Centrefor Clinical Trials and Epidemiological Research, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Keng
Summary Postconcussional complaints are common after mild head injury. These symptoms can be so severe that some patients are unable to return to their previous employment. The purpose of this study is to investigate how important is work-related injury as a factor in determining the degree of disability caused by postconcussional symptoms. We studied 67 patients suffering from postconcussion syndrome after a mild head injury. These patients were divided into two groups, work-related injury and non-work-related injury. The results of this study demonstrated that the median duration of sick leave and the median amount of compensation were significantly higher in the work-related group (8 months vs. 1 month, P = 0.0007; US$9000 vs. US$500, P = 0.0035, respectively). Only 41% of the work-related injured patients returned to work, compared with 85.7% in the nonwork-related injury group (P = 0.0022). The results of this study strongly suggested that work-related injury is a significant factor in determining the degree of disability associated with postconcussion syndrome. Keywords: mild head injury, postconcussion syndrome, compensation
INTRODUCTION
Mild head injury contributes over 80% of all head injury admissions in most studies. The term mild head injury is misleading since many patients will continue to have symptoms, even months after the initial injury. These symptoms are: headache, dizziness, blurred vision, poor memory, and/or fatigue, and they constitute the so-called 'postconcussion syndrome' (PCS). Since all these symptoms of PCS are subjective complaints, the debate regarding their veracity is still alive and well. 1-6 There are studies to show that late symptoms, i.e. those symptoms persisting for more than a few weeks, are caused by an interplay of organic and neurotic factors5 ,8 Other studies also show that late symptoms are closely related to litigation or compensation. 9,1° On the other hand, persistent symptoms after mild head injury are well documented, lt,12 including the detailed description of the symptoms by a prominent neurosurgeon who became a victim of mild head injury.13 The sequelae of mild head injury have also been evaluated objectively by using neuropsychological testing. While there are reports to support the presence of cognitive impairment after mild head injury, 11']2'14'15there are also well conducted studies to show the contrary.16 How real the symptoms of PCS are is still open to debate. The purpose of this study is not to validate PCS. Instead, we would like to show that work-related injury is a significant factor in determining the severity of PCS. METHODS
During the period of July 1994 to October 1995, patients with postconcussional complaints after mild head injury seen in the Neurosurgical Clinic of the Prince of Wales Hospital were studied. Received 29 August 1996 Accepted 18 November 1996 Correspondence to: John N. K. Hsiang, Tel: 852 2632 2624, Fax: 852 2637
0979
All patients entered during this period were prospectively followed in the clinic; however, their initial injury data was collected retrospectively. Mild head injury was defined as Glasgow coma scale (GCS) scores 13-15 with or without loss of consciousness. The GCS score was obtained from the records of Accident and Emergency Department where the patients initially presented after the injury. Patients who had deteriorated to GCS less than 13 or patients who had any neurosurgical interventions such as craniotomy or intracranial pressure (ICP) monitor placement were excluded from this study. Postconcussional syndrome in this study was defined as persistent symptoms related to the head injury for more than 1 month after the injury. These symptoms included headache, dizziness, vertigo, nausea, insomnia, tinnitis, body ache, blurred vision, diplopia, memory impairment, slow response, poor concentration, fatigue and general malaise. The postconcussional symptoms were not asked in a structured way. Instead, the patients were allowed to volunteer the complaining symptoms spontaneously so that no influence from the examiners would be introduced to the patients. All patients had skull X-ray when first seen in the hospital, but not all of them had head computed tomography (CT) scan performed. For all those patients enrolled in the study, their demographic data, initial GCS scores, mechanism of injury, complaining symptoms, work-related or not, length of sick leave and amount of compensation were recorded. Follow-up of these patients was conducted in the neurosurgical clinic. Treatments included reassurance and medications; there was no counselling available to our patients. This study ended on 31 January 1996, and all patients' claims were calculated until this date. The patients in the study were divided into two groups, workrelated (WR) injury group and non-work-related (NWR) injury group. Work-related injury was defined as injury while the patient was on duty. The median duration of sick leave, and the amount of compensation, were compared between the two groups using the Mann-Whitney's test, while the comparison of the proportion of patients returning to work in the two groups was assessed by the Z z test. Statistical significance was defined as P < 0.05 (two-tailed). 399
400
Hsiang et al
RESULTS
DISCUSSION
During the period of July 1994 to October 1995, 67 patients fulfilled the inclusion criteria and were enrolled in the study. There were 39 patients in the WR injury group, and 28 patients in the NWR injury group. In the WR injury group, there were 30 males and 9 females, with an average age of 41.4 (age range 29-68). Seventeen patients worked at construction sites and 5 patients worked as labourers. Hit by falling object (14 patients) was the most common mechanism of head injury, followed by fall from height (12 patients). The earliest injury dated back to April 1992, and the latest injury dated to October 1995. The NWR injury group had 15 males and 13 females, with an average age of 32.3 (age range 6-70). Eight patients were students and seven patients were not employed at the time of injury. Traffic-related accidents (15 patients) and falls (8 patients) accounted for the majority of the injuries. In this group, the earliest injury dated back to May 1992, and the latest injury dated to October 1995. In terms of the severity of injury, in the WR injury group 31 patients had GCS 15, five patients had GCS 14 and three patients had GCS 13. In the NWR injury group, 17 patients had GCS 15, 10 patients had GCS 14 and one patient had GCS 13. The percentage of patients with loss of consciousness after the head injury and the percentage of patients admitted into the hospital were lower in the WR injury group (Table 1). Only 30 patients in the WR injury group had CT scan performed and 10 of these had abnormal CT findings such as fracture, small intracranial haematoma and mild subarachnoid haemorrhage. In the NWR group, 22 patients had CT scan performed, nine of them had abnormal CT findings. The average postconcussional complaints per patient in the WR injury group were 3, whereas the average postconcussional complaints per patient in the NWR group were 2 (Table 1). Both groups cited headache and dizziness as the most frequent complaints. Complaint of poor memory was also common. In the WR injury group, there were more complaints of aches in different body parts. Table 2 shows the comparison of patients' claims and proportion of patients returned to work between the two groups. The median length of sick leave in the WR injury group (8 months) was significantly higher than the NWR injury group (1 month) (P = 0.0007). Similarly, the median amount of compensation in the WR injury group (US$9000) was also significantly higher than the NWR injury group (US$500) (P = 0.0035). Note that the seven unemployed patients in the NWR injury group were excluded from the calculations. The eight students in the NWR injury group were only counted for duration of sick leave but not for the amount of compensation. By the time this study was concluded, only 16 patients (41.0%) in the WR injury group had returned to work, while 18 patients (85.7%) in the NWR injury group had returned to work or to school (P = 0.0022).
Mild head injury is a misleading term since victims of mild head injury can suffer from persistent symptoms which, to some patients, can be disabling. Using GCS scores to define mild head injury is not ideal since GCS was originally designed as a coma scoring system, iv Nevertheless, the definition of GCS 13-15 as mild head injury is well accepted in the literature. In order to minimize the drawbacks of this definition of mild head injury, we only include those patients who did not have any neurosurgical interventions. The results of this study demonstrated that work-related injury is a strong factor in determining the degree of disability caused by postconcussion syndrome after mild head injury. It is possible that the patients in the WR injury group were more seriously injured. This argument, however, is unlikely since the percentage of patients with loss of consciousness after the head injury, the percentage of patients admitted into the hospital, and the percentage of patients with abnormal CT scan were actually higher in the NWR injury group. It is therefore reasonable to assume that some of the work-related injured patients may have exaggerated their postconcussional complaints in order to receive more compensations. It has been suggested that individuals with a mild head injury who have filed for worker's compensation become influenced by the possibility of financial gain. 18 This argument is well illustrated by one of our patients who had been complaining of headache and claiming sick leave for 12 months. He had been receiving compensation of US$1200 per month from the company until he was later discovered working in another place by the private detective hired by the insurance company. The degree of exaggeration of the symptoms of PCS for secondary gains is impossible to measure. It is difficult to identify those patients because postconcussional syndrome is a subjective complaint and there are no reliable objective measures such as imaging studies or cognitive function tests. Neuropsychological testing cannot measure degree of headache or dizziness, but it may be helpful in identifying malingers even though the patients can 'fake bad' on neuropsychological tests. There is study to suggest that comprehensive multidisciplinary evaluations are necessary in detecting malingerers.19 The concept of work-related PCS following mild head injury is not a novel one but the results presented by this study are striking. Perhaps this is particularly prevalent in Hong Kong because of the regulations or by law. In Hong Kong, all work-related injuries can lead to compensation according to the worker compensation scheme. The present system, however, is so full of flaws that a patient can continue to claim sick leave and compensations even 27 months after the initial mild head injury, with no documented loss of consciousness, no hospital admission required, and
Table 1 Characteristics of admission information Work-related injury (n = 39) Number of males (%) Average age Number of patients admitted (%) Number of patients with LOCI (%) Number of patients with abnormal CT findings (%) Average complaints per patient (range)
30 (77.0%) 41.4 27 (69.2%) 24 (61.5%) 10 (33.3%):1: 3 (1-5)
Non-work-related injury (n = 28) 15 (53.6%) 32.3 21 (75%) 22 (78.6%) 9 (40.9%)§ 2 (1-4)
1 LOC = Loss of consciousness. :1:Only 30 patients had CT scan performed. § Only 22 patients had CT scan performed.
Journal of Clinical Neuroscience (1998) 5(4), 399-401
@ Harcourt Brace & Co, Ltd 1998
Work-related postconcussion syndrome Table 2
401
Summary of patients' claims and status after injury between the two groups
Median length of sick leave (range) Median amount of compensation (range) Number of patients return to work (%)
Work-related injury (n = 39)
Nonwork-related injury (n = 28)
P value
8 months (0-27 months) US$9000 ($0-$58 000) 16 (41.0%)
1 month (0-24 months) US$500 ($0-$25 000) 18 (85.7%)1-
0.0007 0.0035 0.0022
1" Seven patients were excluded whose status were either refugees (2), housewives (2), retired (1), or unemployed (2).
a normal CT scan. The patient can claim sick leave as long as he has a written note from any registered doctor in Hong Kong. With that note o f medical sick leave, the patient can continue to claim c o m p e n s a t i o n from the employer, the insurance company, or the Social Welfare Department. One m e t h o d to m i n i m i z e the patient's chance o f abusing the worker c o m p e n s a t i o n s y s t e m is to restrict the patient's choice o f doctors to an appointed, independent group o f doctors, preferably specialists like neurosurgeons or neurologists in cases o f head injury. This system is e m p l o y e d in some Western countries with reasonable success. It would also be helpful if guidelines could be established for the treating physicians who grant the status o f 'not fit for w o r k i n g ' to those patients with PCS after a m i n o r head injury. A patient with no history o f loss o f consciousness and a normal CT is not likely to have a disabling PCS for more than a few months. All physicians who grant the patient the status o f 'not fit for w o r k i n g ' should also be liable by the law. There were eight students included in this study and two o f them were only 6 years old. Obviously their injury was not work-related. Some may argue that only working individuals should be included in this study so that the study population can be more homogenous. However, even though the students cannot claim compensation, they can claim sick leave from school. The inclusion o f this group o f student will help to bring out the striking contrast between the outcome o f the W R injury and N W R injury patients. The purpose o f this study is not to discredit PCS. O n the contrary, this study supports the legitimacy o f postconcussional complaints. Patients in the N W R injury group have genuine complaints. These patients had no obvious secondary gains and they returned to work (or to school) early even in the presence o f postconcussional symptoms. This point is well illustrated in the two 6-year-old pupils w h o did not do as well in school after the mild head injury. Thus, without the motivation o f secondary gains, persistent PCS probably is not severe enough to prevent the patients from working. If a neurosurgeon could return to work immediately after the injury as a full functioning neurosurgeon even in the presence o f PeN, 13it is hard to believe that a labourer cannot return to work months after the initial mild head injury. There is one patient in this N W R group w h o has complained o f headache for more than 2 years after the injury and has not returned to work, but she is also suing the driver w h o hit her for 1 million Hong K o n g dollars. Her lawsuit remains unsettled at the end o f this study. To conclude, postconcussional s y m p t o m s are genuine complaints after mild head injury. M o s t patients can return to work
© Harcourt Brace & Co. Ltd 1998
early after the injury even with persistent symptoms. However, work-related injury is strongly associated with the degree o f disability caused by PCS after mild head injury. The significance o f PCS m a y have been exaggerated in those patients who receive c o m p e n s a t i o n as long as the s y m p t o m s persist. Guidelines for physicians w h o grant these patients the status o f disability need to be established and this m a y help lower the e c o n o m i c and productivity loss caused by postconcussion syndrome.
REFERENCES
1. Field H. Correspondenceon post-traumatic syndrome. J R Soc Med 1981; 74: 630. 2. Field H. Correspondenceon post-traumatic syndrome. J R Soc Med 1981; 74: 941-942. 3. Guthkelch AN. Correspondenceon post-tranmatic syndrome.J R Soc Med 198I; 74: 940. 4. KellyR. The post-traumatic syndrome, an iatrogenic disease. Forensic Sci 1975; 6: 17-24. 5. Kelly R. Correspondenceon post-traumatic syndrome.J R Soc Med i981; 74: 630-631. 6. TrimbleMR. Correspondenceon post-tranmatic syndrome. J R See Med 1981; 74: 940-941. 7. RutherfordWH, Merrett JD, McDonald JR. Sequelae of concussion caused by minor head injuries. Lancet 1977; i: 14. 8. Rutherford WH, Merrett JD, McDonald JR. Symptoms at one year following concussion from minor head injuries. Injury 1978; 10:225 230. 9. Miller SR. Assessmentof motivation and memory with the recognition memory test after financially compensable mild head injury. J Clin Psychol 1994; 50: 601-605. 10. YoungjohnJR, Burrows L, Erdal K. Brain damage or compensationneurosis? The controversialpost-concussion syndrome. Clin Neuropsychol 1995; 9: 112-123. l 1. Bohnen NI, Jolles J, TwijnstraA et al. Neuropsychologicaldeficits in patients with persistent symptoms six months after mild head injury. Neurosurgery 1992; 30: 692-696. i2. BohnenNI, Jolles J, TwijnstraA et al. Late neurobehaviouralsymptoms after mild head injury. Brain Injury 1995; 9: 27-33. 13. Marshall LF, Ruff RM. Neurosurgeonas victim. In: Levin HS, Eisenberg HM, Benton AL (eds). Mild Head Injury. Oxford: 1989: 276-280. 14. Binder LM. Persisting symptoms after mild head injury: a review of the postconcussive syndrome.J Clin Exp Neuropsychoi 1986; 8: 323-346. 15. Rimel RW, Giordani B, Barth JT et al. Disability caused by minor head injury. Neurosurgery 1981; 9: 221-228. 16. Newcombe F, Rabbitt R Briggs M. Minor head injury: pathophysiologicalor iatrogenic sequelae? J NeuroI NeurosurgPsychiatry 1994; 57: 709-716. 17. Teasdale G, Jennett B. Assessment of coma and impaired consciousness:a practical scale. Lancet 1974; 2: 81-84. 18. Keiser L. The Traumatic Neurosis. Philadelphia:Lippincott, 1968. 19. RuffRM, Wylie T, Tennant W. Malingeringmad malingering-likeaspects of mild closed head injury. J Head Trauma RehabiI 1993; 8: 60-73.
Journal of Clinical Neuroscience (1998) 5(4), 399-401
Clinical studies
Postconcussion syndrome following mild head injury: how significant w h e n it is w o r k - r e l a t e d ? John N. K. Hsiang I MD PhD, Wai S. Poon 1 MBChB FRCS(Glasgow),A s h l e y L. M. Yu 2 MSc ~Division of Neurosurgery and 2Centrefor Clinical Trials and Epidemiological Research, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Keng
Summary Postconcussional complaints are common after mild head injury. These symptoms can be so severe that some patients are unable to return to their previous employment. The purpose of this study is to investigate how important is work-related injury as a factor in determining the degree of disability caused by postconcussional symptoms. We studied 67 patients suffering from postconcussion syndrome after a mild head injury. These patients were divided into two groups, work-related injury and non-work-related injury. The results of this study demonstrated that the median duration of sick leave and the median amount of compensation were significantly higher in the work-related group (8 months vs. 1 month, P = 0.0007; US$9000 vs. US$500, P = 0.0035, respectively). Only 41% of the work-related injured patients returned to work, compared with 85.7% in the nonwork-related injury group (P = 0.0022). The results of this study strongly suggested that work-related injury is a significant factor in determining the degree of disability associated with postconcussion syndrome. Keywords: mild head injury, postconcussion syndrome, compensation
INTRODUCTION
Mild head injury contributes over 80% of all head injury admissions in most studies. The term mild head injury is misleading since many patients will continue to have symptoms, even months after the initial injury. These symptoms are: headache, dizziness, blurred vision, poor memory, and/or fatigue, and they constitute the so-called 'postconcussion syndrome' (PCS). Since all these symptoms of PCS are subjective complaints, the debate regarding their veracity is still alive and well. 1-6 There are studies to show that late symptoms, i.e. those symptoms persisting for more than a few weeks, are caused by an interplay of organic and neurotic factors5 ,8 Other studies also show that late symptoms are closely related to litigation or compensation. 9,1° On the other hand, persistent symptoms after mild head injury are well documented, lt,12 including the detailed description of the symptoms by a prominent neurosurgeon who became a victim of mild head injury.13 The sequelae of mild head injury have also been evaluated objectively by using neuropsychological testing. While there are reports to support the presence of cognitive impairment after mild head injury, 11']2'14'15there are also well conducted studies to show the contrary.16 How real the symptoms of PCS are is still open to debate. The purpose of this study is not to validate PCS. Instead, we would like to show that work-related injury is a significant factor in determining the severity of PCS. METHODS
During the period of July 1994 to October 1995, patients with postconcussional complaints after mild head injury seen in the Neurosurgical Clinic of the Prince of Wales Hospital were studied. Received 29 August 1996 Accepted 18 November 1996 Correspondence to: John N. K. Hsiang, Tel: 852 2632 2624, Fax: 852 2637
0979
All patients entered during this period were prospectively followed in the clinic; however, their initial injury data was collected retrospectively. Mild head injury was defined as Glasgow coma scale (GCS) scores 13-15 with or without loss of consciousness. The GCS score was obtained from the records of Accident and Emergency Department where the patients initially presented after the injury. Patients who had deteriorated to GCS less than 13 or patients who had any neurosurgical interventions such as craniotomy or intracranial pressure (ICP) monitor placement were excluded from this study. Postconcussional syndrome in this study was defined as persistent symptoms related to the head injury for more than 1 month after the injury. These symptoms included headache, dizziness, vertigo, nausea, insomnia, tinnitis, body ache, blurred vision, diplopia, memory impairment, slow response, poor concentration, fatigue and general malaise. The postconcussional symptoms were not asked in a structured way. Instead, the patients were allowed to volunteer the complaining symptoms spontaneously so that no influence from the examiners would be introduced to the patients. All patients had skull X-ray when first seen in the hospital, but not all of them had head computed tomography (CT) scan performed. For all those patients enrolled in the study, their demographic data, initial GCS scores, mechanism of injury, complaining symptoms, work-related or not, length of sick leave and amount of compensation were recorded. Follow-up of these patients was conducted in the neurosurgical clinic. Treatments included reassurance and medications; there was no counselling available to our patients. This study ended on 31 January 1996, and all patients' claims were calculated until this date. The patients in the study were divided into two groups, workrelated (WR) injury group and non-work-related (NWR) injury group. Work-related injury was defined as injury while the patient was on duty. The median duration of sick leave, and the amount of compensation, were compared between the two groups using the Mann-Whitney's test, while the comparison of the proportion of patients returning to work in the two groups was assessed by the Z z test. Statistical significance was defined as P < 0.05 (two-tailed). 399
400
Hsiang et al
RESULTS
DISCUSSION
During the period of July 1994 to October 1995, 67 patients fulfilled the inclusion criteria and were enrolled in the study. There were 39 patients in the WR injury group, and 28 patients in the NWR injury group. In the WR injury group, there were 30 males and 9 females, with an average age of 41.4 (age range 29-68). Seventeen patients worked at construction sites and 5 patients worked as labourers. Hit by falling object (14 patients) was the most common mechanism of head injury, followed by fall from height (12 patients). The earliest injury dated back to April 1992, and the latest injury dated to October 1995. The NWR injury group had 15 males and 13 females, with an average age of 32.3 (age range 6-70). Eight patients were students and seven patients were not employed at the time of injury. Traffic-related accidents (15 patients) and falls (8 patients) accounted for the majority of the injuries. In this group, the earliest injury dated back to May 1992, and the latest injury dated to October 1995. In terms of the severity of injury, in the WR injury group 31 patients had GCS 15, five patients had GCS 14 and three patients had GCS 13. In the NWR injury group, 17 patients had GCS 15, 10 patients had GCS 14 and one patient had GCS 13. The percentage of patients with loss of consciousness after the head injury and the percentage of patients admitted into the hospital were lower in the WR injury group (Table 1). Only 30 patients in the WR injury group had CT scan performed and 10 of these had abnormal CT findings such as fracture, small intracranial haematoma and mild subarachnoid haemorrhage. In the NWR group, 22 patients had CT scan performed, nine of them had abnormal CT findings. The average postconcussional complaints per patient in the WR injury group were 3, whereas the average postconcussional complaints per patient in the NWR group were 2 (Table 1). Both groups cited headache and dizziness as the most frequent complaints. Complaint of poor memory was also common. In the WR injury group, there were more complaints of aches in different body parts. Table 2 shows the comparison of patients' claims and proportion of patients returned to work between the two groups. The median length of sick leave in the WR injury group (8 months) was significantly higher than the NWR injury group (1 month) (P = 0.0007). Similarly, the median amount of compensation in the WR injury group (US$9000) was also significantly higher than the NWR injury group (US$500) (P = 0.0035). Note that the seven unemployed patients in the NWR injury group were excluded from the calculations. The eight students in the NWR injury group were only counted for duration of sick leave but not for the amount of compensation. By the time this study was concluded, only 16 patients (41.0%) in the WR injury group had returned to work, while 18 patients (85.7%) in the NWR injury group had returned to work or to school (P = 0.0022).
Mild head injury is a misleading term since victims of mild head injury can suffer from persistent symptoms which, to some patients, can be disabling. Using GCS scores to define mild head injury is not ideal since GCS was originally designed as a coma scoring system, iv Nevertheless, the definition of GCS 13-15 as mild head injury is well accepted in the literature. In order to minimize the drawbacks of this definition of mild head injury, we only include those patients who did not have any neurosurgical interventions. The results of this study demonstrated that work-related injury is a strong factor in determining the degree of disability caused by postconcussion syndrome after mild head injury. It is possible that the patients in the WR injury group were more seriously injured. This argument, however, is unlikely since the percentage of patients with loss of consciousness after the head injury, the percentage of patients admitted into the hospital, and the percentage of patients with abnormal CT scan were actually higher in the NWR injury group. It is therefore reasonable to assume that some of the work-related injured patients may have exaggerated their postconcussional complaints in order to receive more compensations. It has been suggested that individuals with a mild head injury who have filed for worker's compensation become influenced by the possibility of financial gain. 18 This argument is well illustrated by one of our patients who had been complaining of headache and claiming sick leave for 12 months. He had been receiving compensation of US$1200 per month from the company until he was later discovered working in another place by the private detective hired by the insurance company. The degree of exaggeration of the symptoms of PCS for secondary gains is impossible to measure. It is difficult to identify those patients because postconcussional syndrome is a subjective complaint and there are no reliable objective measures such as imaging studies or cognitive function tests. Neuropsychological testing cannot measure degree of headache or dizziness, but it may be helpful in identifying malingers even though the patients can 'fake bad' on neuropsychological tests. There is study to suggest that comprehensive multidisciplinary evaluations are necessary in detecting malingerers.19 The concept of work-related PCS following mild head injury is not a novel one but the results presented by this study are striking. Perhaps this is particularly prevalent in Hong Kong because of the regulations or by law. In Hong Kong, all work-related injuries can lead to compensation according to the worker compensation scheme. The present system, however, is so full of flaws that a patient can continue to claim sick leave and compensations even 27 months after the initial mild head injury, with no documented loss of consciousness, no hospital admission required, and
Table 1 Characteristics of admission information Work-related injury (n = 39) Number of males (%) Average age Number of patients admitted (%) Number of patients with LOCI (%) Number of patients with abnormal CT findings (%) Average complaints per patient (range)
30 (77.0%) 41.4 27 (69.2%) 24 (61.5%) 10 (33.3%):1: 3 (1-5)
Non-work-related injury (n = 28) 15 (53.6%) 32.3 21 (75%) 22 (78.6%) 9 (40.9%)§ 2 (1-4)
1 LOC = Loss of consciousness. :1:Only 30 patients had CT scan performed. § Only 22 patients had CT scan performed.
Journal of Clinical Neuroscience (1998) 5(4), 399-401
@ Harcourt Brace & Co, Ltd 1998
Work-related postconcussion syndrome Table 2
401
Summary of patients' claims and status after injury between the two groups
Median length of sick leave (range) Median amount of compensation (range) Number of patients return to work (%)
Work-related injury (n = 39)
Nonwork-related injury (n = 28)
P value
8 months (0-27 months) US$9000 ($0-$58 000) 16 (41.0%)
1 month (0-24 months) US$500 ($0-$25 000) 18 (85.7%)1-
0.0007 0.0035 0.0022
1" Seven patients were excluded whose status were either refugees (2), housewives (2), retired (1), or unemployed (2).
a normal CT scan. The patient can claim sick leave as long as he has a written note from any registered doctor in Hong Kong. With that note o f medical sick leave, the patient can continue to claim c o m p e n s a t i o n from the employer, the insurance company, or the Social Welfare Department. One m e t h o d to m i n i m i z e the patient's chance o f abusing the worker c o m p e n s a t i o n s y s t e m is to restrict the patient's choice o f doctors to an appointed, independent group o f doctors, preferably specialists like neurosurgeons or neurologists in cases o f head injury. This system is e m p l o y e d in some Western countries with reasonable success. It would also be helpful if guidelines could be established for the treating physicians who grant the status o f 'not fit for w o r k i n g ' to those patients with PCS after a m i n o r head injury. A patient with no history o f loss o f consciousness and a normal CT is not likely to have a disabling PCS for more than a few months. All physicians who grant the patient the status o f 'not fit for w o r k i n g ' should also be liable by the law. There were eight students included in this study and two o f them were only 6 years old. Obviously their injury was not work-related. Some may argue that only working individuals should be included in this study so that the study population can be more homogenous. However, even though the students cannot claim compensation, they can claim sick leave from school. The inclusion o f this group o f student will help to bring out the striking contrast between the outcome o f the W R injury and N W R injury patients. The purpose o f this study is not to discredit PCS. O n the contrary, this study supports the legitimacy o f postconcussional complaints. Patients in the N W R injury group have genuine complaints. These patients had no obvious secondary gains and they returned to work (or to school) early even in the presence o f postconcussional symptoms. This point is well illustrated in the two 6-year-old pupils w h o did not do as well in school after the mild head injury. Thus, without the motivation o f secondary gains, persistent PCS probably is not severe enough to prevent the patients from working. If a neurosurgeon could return to work immediately after the injury as a full functioning neurosurgeon even in the presence o f PeN, 13it is hard to believe that a labourer cannot return to work months after the initial mild head injury. There is one patient in this N W R group w h o has complained o f headache for more than 2 years after the injury and has not returned to work, but she is also suing the driver w h o hit her for 1 million Hong K o n g dollars. Her lawsuit remains unsettled at the end o f this study. To conclude, postconcussional s y m p t o m s are genuine complaints after mild head injury. M o s t patients can return to work
© Harcourt Brace & Co. Ltd 1998
early after the injury even with persistent symptoms. However, work-related injury is strongly associated with the degree o f disability caused by PCS after mild head injury. The significance o f PCS m a y have been exaggerated in those patients who receive c o m p e n s a t i o n as long as the s y m p t o m s persist. Guidelines for physicians w h o grant these patients the status o f disability need to be established and this m a y help lower the e c o n o m i c and productivity loss caused by postconcussion syndrome.
REFERENCES
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Journal of Clinical Neuroscience (1998) 5(4), 399-401