CLINICAL DECISION INSTRUMENTS FOR CT SCAN IN MINOR HEAD TRAUMA by Clark1968

doi:10.1016/j.jemermed.2007.05.055

Original Contributions

CLINICAL DECISION INSTRUMENTS FOR CT SCAN IN MINOR HEAD TRAUMA Süleyman Türedi,

MD,*

Altug Hasanbasoglu,

MD,†

Abdulkadir Gunduz,

MD,*

and Mustafa Yandi,

MD,‡

*Department of Emergency Medicine, Karadeniz Technical University Faculty of Medicine, Trabzon, Turkey, †Department of Emergency Medicine, Mesa Hospital, Ankara, Turkey, and ‡Department of General Surgery, Karadeniz Technical University Faculty of Medicine, Trabzon, Turkey Reprint Address: Süleyman Türedi, MD, Department of Emergency Medicine, Karadeniz Technical University School of Medicine, Trabzon 61080, Turkey

e Abstract—Previous studies have presented conflicting results regarding the predictive value of various clinical symptoms and signs for performing computed tomography (CT) scan in minor head injury. Moreover, despite the presence in the literature of several similar publications regarding whether or not CT should be employed at the time of presentation of minor head injured patients, data regarding delayed CT are limited. The objective of this study was to determine whether high-risk criteria represent a significant indication for initial CT scan in patients with minor head trauma, and whether or not analysis using delayed CT scan is necessary in patients with high-risk criteria before being discharged. Patients presenting to the Emergency Department with minor head trauma between September 1, 2003 and September 1, 2004 were evaluated prospectively. After being divided into two main groups, low- and high-risk, four separate sub-groups based on age were established. Initial spiral CT examination was done within 3 h of trauma on all patients in addition to a delayed control CT scan in those with high-risk criteria between 16 and 24 h after trauma. The difference between the highand low-risk groups in terms of abnormal CT findings was statistically significant (p < 0.0005). Among high-risk patients there was a significant difference between patients with a Glasgow Coma Scale (GCS) score of 13 or 14 and those with a GCS score of 15 (p < 0.0005). The relationship between vomiting and abnormal CT scan was significant (odds ratio 4.61, 95% confidence interval 2.20 –9.64, p ⴝ 0.0001), and the relationship between abnormal CT scan and suspected skull fracture was also significant (odds ratio 3.46, 95% confidence interval 1.52–7.91, p ⴝ 0.0032). No

RECEIVED: 18 August 2006; FINAL ACCEPTED: 6 May 2007

SUBMISSION RECEIVED:

significant correlations between other high-risk criteria and abnormal CT scan were determined. The difference between initial and delayed CT scans in patients with highrisk criteria was not significant (p ⴝ 0.161). Low-risk patients with a GCS score of 15 may be discharged without initial CT scan being performed. Initial CT scan absolutely must be performed, however, on patients with GCS < 15 in the event of vomiting or suspected skull fracture, even if isolated. Even though the difference between initial and delayed CT scans in patients with high-risk criteria is not significant, it is our opinion that it is still prudent for delayed CT scan to be performed, particularly on patients whose GCS score does not rise to 15, or decreases. © 2008 Elsevier Inc. e Keywords—minor head trauma; initial CT; delayed CT

INTRODUCTION Minor head injury is one of the most common injuries in the Western world, with an estimated incidence of 100 to 300 per 100,000 people (1). Minor head injury is commonly defined as blunt trauma to the head, after which the patient loses consciousness for ⬍15 min or has a short, post-traumatic amnesia of ⬍1 h, or both, as well as a normal or minimally altered mental status on presentation (a Glasgow Coma Scale [GCS] score of 13–15) (2). Intracranial complications of minor head injury are infrequent (6 –21%) but potentially life-threatening, and

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may require neurosurgical intervention in a minority of cases (0.4 –1.0%) (3). In cases of head trauma, computed tomography (CT) scan is essential for all patients with a GCS score of 13 or less, whereas only a specific history, symptom, or physical examination finding makes CT scan necessary in patients with a GCS score of 15 or rising to 15 post-resuscitation. These findings, known as high-risk criteria, include: amnesia, loss of consciousness, vomiting, suspected skull fracture, a history of coagulopathy or anticoagulant use, focal neurological findings, post-traumatic seizures, severe or increasing headache, asymmetric pupils, or multiple trauma (4). Algorithms for the management of minor head injury have been proposed for these high-risk criteria (5). Many studies have been conducted on this subject and algorithms developed with regard to the use of CT scan in patients with minor head trauma (6). The question still remains, however, whether all patients with a clinically significant lesion on CT scan really do require observation and, consequently, whether a CT scan is really indicated (3). Our study was performed to determine whether high-risk criteria represent a significant indication for initial CT scan in patients with minor head trauma, and whether or not analysis using delayed CT scan is necessary in patients with high-risk criteria before being discharged.

METHODS This study was conducted at the Karadeniz Technical University Emergency Department. After approval was obtained from the Local Ethical Committee, minor head injured patients presenting to the Emergency Department between September 1, 2003 and September 1, 2004 were evaluated prospectively. All patients presenting to the Emergency Department within 3 h of minor head trauma were included in the study, without regard to gender or age. Minor head injury is defined as blunt trauma to the head, after which the patient loses consciousness for ⬍15 min or has a short, post-traumatic amnesia of ⬍1 h, or both, as well as a normal or minimally altered mental status on presentation (a GCS score of 13–15). A history of loss of consciousness, amnesia, vomiting, suspected skull fracture, presence of multiple trauma, severe or increasingly severe headache, asymmetric pupils, focal neurological findings, post-traumatic seizures, a history of coagulopathy or continuing anticoagulant treatment, and a GCS score of 14 or 15 were determined as high-risk criteria in patients with minor head injury. After patients had been divided into two main groups, high- and low-risk, they were further divided into four

age sub-groups. These were determined as 0 – 6 years, 7–16 years, 17– 60 years, and over 60 years. Certain groups closed to enrollment while others went on in order to achieve 30 patients in all groups. In this way, low- and high-risk sub-groups consisting of 30 patients each in every age group were established, and a total of 240 patients were evaluated. Initial CT examination was done within 3 h of trauma on all patients, in addition to a delayed CT scan in those with high-risk criteria, between 16 and 24 h after trauma. CT scan was performed according to a routine trauma protocol, which consisted of a maximum slice thickness of 5 mm infratentorially and 8 mm supratentorially, without intravenous contrast administration. All scans were interpreted by several radiologists blinded to the presence or absence of high-risk criteria in a bone and brain windows setting. Data were collected on patient and trauma characteristics (age, sex, time of injury, and presentation), accompanying symptoms (loss of consciousness, post-traumatic amnesia, post-traumatic seizures, headache, vomiting), physical and neurological examination, CT scan findings, a history of anticoagulant treatment or presence of coagulopathy, and the need for surgical intervention. Selection of these items was based on a literature review of published risk factors for intracranial complications after minor head injury. A neurosurgical intervention was defined as any neurosurgical procedure within 30 days after the traumatic event. During statistical analysis, quantitative data were analyzed using the chi-squared test. The Yates correction was used for a value ⬍25 on the 2 ⫻ 2 matrix, and the Fisher’s exact test for a value ⬍5. Abnormal CT scan findings as the dependent variable were compared to high-risk factors as independent variables using logistic regression analysis.

RESULTS Included in the study were 240 patients with minor head injury presenting to the Karadeniz Technical University

Table 1. Age Distribution of Initial Abnormal CT Scan Findings in Patients with High-risk Criteria Age Group

Abnormal CT Scan Number

Abnormal CT Scan Percentage

0–6 years 7–16 years 17–60 years Over 60

30 30 30 30

13 12 9 5

43% 40% 30% 16%

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Table 2. Age Distribution of Initial Abnormal CT Scan Findings in Patients with Low-risk Criteria Age Group

Abnormal CT Scan Number

Abnormal CT Scan Percentage

0–6 years 7–16 years 17–60 years Over 60 years

30 30 30 30

4 3 1 0

13% 10% 3% 16%

Medical Faculty Emergency Department in the 1-year study period. Initial CT scan was performed on all 240 patients investigated within the first 3 h. As a result of this initial CT scan, abnormal findings were identified in 47 (19%) patients overall. The number of patients with abnormal CT scan findings in the high-risk group was 39 (32%), and 8 (6%) in the low-risk group. Patients in the highrisk group had significantly more abnormal CT scan findings than patients in the low-risk group (p ⬍ 0.0005). The age distribution of patients with abnormal CT scan findings and with high-risk criteria is shown in Table 1; there were no statistically significant differences between the age groups (p ⫽ 0.165). The age distribution of patients with abnormal CT scan findings and with low-risk criteria is shown in Table 2; there were no statistically significant differences between the age groups (p ⫽ 0.069). All of these 8 patients were discharged without the need for surgical intervention. The GCS scores of the 120 patients in the low-risk group in our study were all 15; in the 120 patients in the high-risk group, it varied between 13 and 15. The distribution of patients with high-risk criteria with normal vs. abnormal CT scan by GCS score is shown in Table 3. There was a significant difference between normal and abnormal CT scans in high-risk patients with minor head injury and a GCS score of 13 or 14 vs. patients with a GCS score of 15 on initial CT scan (p ⬍ 0.0005). The correlation between high-risk criteria and abnormal CT scan was analyzed. These findings are shown in Tables 4 and 5. There was a significant correlation of

abnormal CT scan with vomiting and with suspected skull fracture, but no significant correlation with amnesia, loss of consciousness, headache, or presence of multi-trauma. Insufficient data were available to permit an analysis of correlation between other high-risk criteria and abnormal CT scan. Delayed CT scan in all 120 patients with high-risk criteria was performed within 16 –24 h of the incident. Different findings between initial and delayed CT scans were found in only three of these cases, and this difference was not statistically significant (p ⫽ 0.161). The initial and delayed CT scan findings of these three cases are shown in Table 6.

DISCUSSION The relevant literature contains many studies on the use of CT scan in patients with minor head injury, yet no consensus has been reached. A study by Haydel et al. suggested that CT scan is indicated only in patients with minor head injury with any one of seven risk factors, the New Orleans Criteria (7). According to this decision rule, patients without any risk factors would not require CT scan. A similar study by Stiell et al. identified a different set of factors, the Canadian CT Head Rule (8). Both decision rules had 100% sensitivity for identifying patients with traumatic brain injury, but both rules had low specificities (9). These rules are shown in Figure 1. Servadei et al. classified patients with minor head injury as low-, medium-, or high-risk (10). They evaluated patients with a GCS score of 15 and with no temporary loss of consciousness, amnesia, and vomiting or widespread headache as low-risk and determined the risk of intracranial hemorrhage requiring surgical intervention in these patients as ⬍0.2%. Servadei et al., therefore, suggested that such patients may be discharged without the need for CT examination. Patients with one or more of these four symptoms (temporary loss of consciousness, amnesia, vomiting, or widespread headache) were

Table 3. Distribution of Patients with Normal vs. Abnormal CT Scans by Glasgow Coma Scale (GCS) Score, in High-risk Patients on Initial CT Scan GCS 15 14 13

Number of Patients

Normal CT Scan Number

Normal CT Scan Percentage

Abnormal CT Scan Number

Abnormal CT Scan Percentage

94 12 14

72 5 2

76% 41% 14%

22 7 12

24% 59% 86%

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Table 4. Correlation between High-risk Criteria and Initial Abnormal CT Scan in All Patients (n ⴝ 240) High-risk Criteria

Number of Patients and Percentage

Abnormal CT Scan Number

Abnormal CT Scan Percentage

Vomiting Suspected skull fracture Loss of consciousness Amnesia Multi-trauma Headache Asymmetric pupils Focal neurological finding Seizure Coagulopathy Anticoagulant treatment

63 (26%) 40 (16.5%) 17 (7%) 29 (12) 39 (16%) 10 (64.2%) 1 (0.4%) 0 (0%) 1 (0.4%) 0 (0%) 0 (0%)

28 19 7 9 8 3 1 0 1 0 0

44.5% 47.5% 41% 31% 20.5% 20.5% 100% 0% 100% 0% 0%

classified as medium-risk head injury, and the risk of intracranial hemorrhage in these patients was determined to be 1–3%. They recommended CT scan for mediumrisk patients. They classified patients with a GCS score of 14 or 15 at presentation together with suspected skull fracture or neurological deficit as high risk, and determined the risk of intracranial hemorrhage as 6 –10%, and emphatically advised that CT scan be performed (10). In our study, similarly, abnormal CT scan findings were present in 8 (6%) of the 120 patients in the low-risk group, and these patients were discharged without the need for any surgical intervention. We believe that patients in the low-risk group can be safely discharged without the need for CT scan. The difference in abnormal CT findings between patients with high-risk criteria and patients with low-risk criteria was significant for the initial CT scan. We be-

p Value

Could Could Could Could Could

⬍0.0005 ⬍0.0005 0.059 0.25 1 0.713 not be evaluated not be evaluated not be evaluated not be evaluated not be evaluated

lieve that this result shows that initial CT scan is indicated in patients with high-risk criteria. In addition, we analyzed whether there was a difference among the highrisk criteria in our study. The first risk factor, vomiting, was present in 63 patients. There were abnormal CT scan findings in 28 of these, and 2 were sent for surgery. Nineteen patients presented with an isolated complaint of vomiting, and abnormal CT scan findings were present in 6 of these. This correlation between vomiting and abnormal CT scan was significant. Many reports in the literature state that vomiting, even on its own, is an indication for CT scan (11,12). Skull fracture was suspected in 40 patients. Abnormal CT scan findings were observed in 19 of these, and 2 required surgical intervention. Four cases presented with an isolated suspected skull fracture, and abnormal CT

Table 5. High-risk Criteria and Initial Abnormal CT Scan Findings: Results of Logistic Regression Analysis High-risk Criteria

Initial Abnormal CT Scan Findings

No Yes

1 4.61

No Yes

1 3.46

No Yes

1 0.89

No Yes

1 1.52

No Yes

1 0.86

No Yes

1 2.51

95% CI

Vomiting

0.0001 2.20–9.64

Suspected skull fracture

0.0032 1.52–7.91

Amnesia

0.8251 0.32–2.48

Loss of consciousness

0.4895 0.46–4.99

Multi-trauma

0.7583 0.33–2.23

Headache

OR ⫽ odds ratio; CI ⫽ confidence interval. Constant B ⫽ ⫺2.237, p ⬍ 0.0005.

p Value

0.2379 0.54–11.62

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Table 6. Patients in the High-risk Group with Different Pathological Findings on Initial vs. Delayed CT Scan Initial CT scan

Delayed CT scan

Patient 1 Patient 2

Normal Linear fracture

Patient 3

Linear fracture

Epidural hematoma Linear fracture âŤš epidural hematoma Linear fracture âŤš contusion

scan findings were present in 2 of these. This correlation between abnormal CT scan and suspected skull fracture was significant. This is in agreement with a correlation reported for a similar study by Stiell et al. (8). Loss of consciousness was present in 17 patients. Abnormal CT scan findings were identified in only 7 of these cases, and no significant correlation was found between loss of consciousness and abnormal CT scan. One additional risk factor was present in 15 of our patients presenting with loss of consciousness, of a confirmatory nature, and 2 of these patients presented with isolated loss of consciousness, CT scan being normal in both. In the literature, in contrast to our study, Stein et al. suggested that CT scan should be performed in all patients with minor head injury and loss of consciousness (13). Similar to our study, Gomez et al. and Falamirski et al. reported that loss of consciousness did not indicate severe head trauma and did not, on its own, indicate the need for CT scan (14,15). The correlation between amnesia and abnormal CT scan was not significant. Amnesia was present in 29 of our cases, and abnormal CT scan was determined in nine of these, and one required surgical intervention (skull fracture in addition to amnesia). Only four of these 29 cases had amnesia as an isolated complaint, and CT scan was normal in all of them. Stein et al. recommended that CT scan be performed in all patients with amnesia (13). Conversely, Murshid reported that there is no need to perform CT scan on minor head injury patients with isolated amnesia (16). We believe the results of our study indicate that CT scan need not be performed on minor head injury patients with isolated amnesia. Yamaguchi proposed that the lower the head injury severity, the greater the prevalence of headache, and also determined an inverse correlation between the frequency of headache observation and abnormal CT scan findings (17). In contrast, Murshid stated that progressive headache represents an indication for CT scan (16). In our study, severe or increasingly severe headache was present in 10 patients, and abnormal CT scan findings were present in 3 of them. The number of patients presenting with isolated headache was 2, and CT scan was normal in both. Our study found no significant

correlation between headache and abnormal CT scan findings. We believe that isolated headache is not an indication for CT scan in patients with minor head trauma. The number of patients with multi-trauma was 39, and abnormal CT scan findings were present in 8 of these. Fifteen patients had multi-trauma and no other risk factors, and there was an abnormal CT scan finding in only 1 of these. Statistically, there was no correlation between multi-trauma and abnormal CT scan; we believe that it is not by itself an indication for initial CT scan. Similar analyses for the other risk factors could not be performed due to inadequate patient numbers. Despite the presence in the literature of several similar studies examining whether or not initial CT scan should be employed at the time a patient presents with minor head injury, data regarding delayed CT scan are limited. In one study, Arienta et al. stated that CT scan should be performed immediately on patients with at least one of the following criteria: insufficient consciousness, repeated vomiting, focal neurological findings, posttraumatic seizures, otorrhea, rhinorrhea, penetration injury, or a history of intracranial operation; and that, if considered necessary, delayed CT scan should be performed before discharge (12). A study by the Study Group on Head Injury of the Italian Society for Neurosurgery, on the other hand, stated that delayed CT scan need only be performed before discharging patients with minor head trauma receiving coagulopathy or still receiving anticoagulant treatment in the event of any lesion

Figure 1. The New Orleans and Canadian CT rules.

258

at initial CT scan (18). Davis et al. stated that among children with a normal cranial CT scan after minor head injury, delayed intracranial sequelae requiring intervention are extremely uncommon. A normal initial CT scan identified patients to be safely discharged from the Emergency Department (19). In an another study, Livingston et al. reported that patients with a cranial CT scan obtained on a helical CT scanner, showing no intracerebral injury, and who do not have other body system injuries or a persistence of any neurologic finding can be safely discharged from the Emergency Department without a period of either inpatient or outpatient observation (20). However, Riesgo et al. reported that normality of an early CT scan does not rule out further development of delayed traumatic lesions. A delayed CT examination, in their view, should be carried out as soon as any impairment in the neurological situation of the patient is noted (21). In our study, delayed CT scan was performed on all 120 patients with a high-risk factor. A difference between initial and delayed CT scan was found in only 3 of these patients. The first case was a 5-year-old boy with a GCS score of 15. Before initial CT scan, he had complaints of vomiting at least 10 times and temporary loss of consciousness for 10 min. Linear fracture alone was observed at initial CT scan. At delayed CT scan, performed despite the absence of any other finding at initial CT scan and with no clinical change in the patient, an epidural hematoma, 0.4 cm at its widest point, was identified. The patient was discharged in a healthy condition without the need for surgical intervention. The second case was a 9-year-old boy with a GCS score of 14. Agitation was observed at presentation and he vomited twice before reaching the hospital. No pathological finding was determined at initial CT scan. Vomiting continued after initial CT scan and inclination to sleep increased. A 0.3-cm epidural hematoma was found at delayed CT scan. He was discharged in a healthy condition without the need for surgical intervention. The last case was a 32-year-old woman with a GCS score of 14 at presentation. She had high-risk criteria including suspected skull fracture, vomiting, and multitrauma. Only a linear fracture was determined at initial CT scan. At delayed CT scan, performed on the patient in whom the GCS score had not increased, intraparenchymal contusion was determined. This patient also was discharged in a healthy condition without the need for surgical intervention. Taking the total of 120 cases as a whole, the difference between initial and delayed CT scan was not significant. In conclusion, we recommend that low-risk patients with a GCS score of 15 may be safely discharged without a CT scan being performed. Initial CT scan absolutely must be performed on patients with GCS score of 15 or

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lower, or with vomiting or suspected skull fracture, even if isolated. Although the difference between initial and delayed CT scans in patients with high-risk criteria was not significant in our study, we think it prudent that delayed CT scan be performed on patients whose GCS score fails to rise to 15 or decreases. Finally, there is a need for wider studies containing greater numbers of patients to evaluate all highrisk factors in relation to indications for delayed CT scan in patients with minor head injuries. REFERENCES 1. Cassidy J, Carroll L, Peloso P, et al. Incidence, risk factors and prevention of mild traumatic brain injury: results of the WHO Collaborating Centre Task Force on Mild Traumatic Brain Injury. J Rehabil Med 2004;43:28 – 60. 2. Carroll LJ, Cassidy JD, Holm L, et al. Methodological issues and research recommendations for mild traumatic brain injury: the WHO Collaborating Centre Task Force on Mild Traumatic Brain Injury. J Rehabil Med 2004;43:113–25. 3. Smits M, Dippel DWJ, Haan GG, et al. External validation of the Canadian CT head rule and the New Orleans criteria for CT scanning in patients with minor head injury. JAMA 2005;294: 1519 –25. 4. Dunning J, Batchelor J, Stratford-Smith P, et al. A meta-analysis of variables that predcit significant intracranial injury in minor head trauma. Arch Dis Child 2004;89:653–9. 5. Kirsch TD, Migliore S, Hogan TM. Head injury. In: Tintinalli JE, Kelen GD, Stapczynski SJ. Emergency medicine, 5th edn. New York: McGraw Hill; 2000:1631– 45. 6. Sultan HY, Boyle A, Pereira M, et al. Application of the Canadian CT head rules in managing minor head injuries in a UK emergency department: implications for the implementation of the NICE guidelines. Emerg Med J 2004;21:420 –5. 7. Haydel MJ, Preston CA, Mills TJ, et al. Indications for computed tomography in patients with minor head injury. N Engl J Med 2000;343:100 –5. 8. Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet 2001;357: 1391– 6. 9. Graham ID, Stiell IG, Laupacis A, et al. Emergency physicians’ attitudes toward and use of clinical decision rules for radiography. Acad Emerg Med 1998;5:134 – 40. 10. Servadei F, Teasdale G, Merry G. Neurotraumatology Committee of the World Federation of Neurosurgical Societies. Defining acute mild head injury in adults: a proposal based on prognostic factors, diagnosis and management. J Neurotrauma 2001;18:657– 64. 11. Nee PA, Hadfield JM, Yates DU, et al. Significance of vomiting after head injury. J Neurol Neurosurg Psychiatry 1999;66:470 –3. 12. Arienta C, Caroli M, Balbi S. Management of head injured patients in the emergency department: a practical protocol. Surg Neurol 1997;48:213–9. 13. Stein SC, O’Malley KF, Ross E. Is routine computed tomography scanning too expensive for mild injury? Ann Emerg Med 1991; 20:1236 –9. 14. Gomez PA, Lobato RD, Ortega JM, et al. Mild head injury: differences in prognosis among patients with a Glasgow Coma Scale of 13 to 15 and analysis of factors associated with abnormal CT findings. Br J Neurosurg 1996;10:453– 60. 15. Falimirski ME, Gonzales R, Rodriguez A, et al. The need for head computed tomography in patients sustaining loss of consciousness after mild head injury. J Trauma 2003;55:1– 6. 16. Murshid WR. Management of minor head injuries: admission criteria, radiological evaluation and treatment of complication. Acta Neurochir 1998;140:56 – 64. 17. Yamaguchi M. Incidence of headache and severity of head injury. Headache 1992;32:427–31.

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259 20. Livingston DH, Lavery RF, Passannante MR, et al. Emergency department discharge of patients with a negative cranial computed tomography scan after minimal head injury. Ann Surg 2000;232:126–32. 21. Riesgo P, Piquer J, Botella C, et al. Delayed extradural hematoma after mild head injury: report of three cases. Surg Neurol 1997;48: 226 –31.