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Update: Do Patients With Minor Head Trauma Require Neuroimaging?
TRAUMA/SYSTEMATIC REVIEW SNAPSHOT
TAKE-HOME MESSAGE Negative results for Canadian CT Head Rule or New Orleans Criteria can identify patients with minor head trauma for whom routine neuroimaging is unlikely to identify a clinically significant intracranial injury (<1%). High-risk features should prompt providers to consider neuroimaging. Update: Do Patients With Minor Head Trauma Require Neuroimaging?
METHODS
EBEM Commentators
DATA SOURCES The authors performed a systematic search of MEDLINE and the Cochrane Library through August 2015 to identify studies assessing the diagnosis of traumatic intracranial injuries. The authors also reviewed articles in the authors’ files, article references, and textbook references for additional articles. STUDY SELECTION English-language studies with greater than 50% of the participants older than 18 years and with a minor head injury, defined as a Glasgow Coma Scale (GCS) score of 13 to 15, were included. All studies measured the performance of history and physical examination findings for identifying intracranial injury, with a reference standard of neuroimaging or follow-up evaluation. The authors defined intracranial injury a priori as any of the following: subdural, epidural, ventricular, or parenchymal hematoma; subarachnoid hemorrhage; herniation; or depressed skull fracture.
Melody Milliron, DO Jestin N. Carlson, MD, MS Department of Emergency Medicine Saint Vincent Hospital Erie, PA
Results Table 1. LRs of various risk factors, signs, and symptoms of patients with mild traumatic brain injury for severe intracranial injury. Characteristics
Volume
-,
no.
-
:
-
2016
LRD (95% CI)*
LR– (95% CI)*
2
3–4.3
0.87–0.93
3
3.6 (3.1–4.1)
0.76 (0.61–0.95)
3 5
16 (3.1–59) 6 (3.9–8)
0.85 (0.48–0.98) 0.84 (0.76–0.92)
2 3 3 2
3.4–16 3.5 (1.6–7.6) 4.9 (2.8–8.5) 1.9–7
0.76–0.8 0.63 (0.45–0.89) 0.88 (0.84–0.93) 0.91–0.96
Risk factors Mechanism of injury Pedestrian struck Symptoms Vomiting, >2 episodes Signs Skull fracture Any Basal GCS score Any decline <15 at 2 h Initial score 13 Focal neurologic deficit
LRþ, Positive LR; CI, confidence interval; LR–, negative LR. *Findings from 2 studies are reported as ranges. Findings from more than 3 studies are reported as summary measures with 95% CI.
Table 2. Accuracy of clinical decision rules for identifying severe intracranial injury in patients with mild traumatic brain injury and loss of consciousness, amnesia, or disorientation.
Rule
DATA EXTRACTION AND SYNTHESIS Three investigators independently assessed qualifying studies undergoing full-text review and assigned a Rational Clinical
No. of Studies
Canadian CT Head Rule New Orleans Criteria
No. of Studies
LRD (95% CI)
LR– (95% CI)
Probability of Severe Intracranial Injury if No Findings Present (95% CI)
5 5
1.6 (1.5–1.8) 1.1 (1.1–1.2)
0.04 (0–0.65) 0.08 (0.01–0.84)
0.31 (0–4.7) 0.61 (0.08–6)
Of 2,670 potential studies, the authors identified 14 meeting the inclusion criteria, which included a total of 23,079 patients with minor
head trauma. Clinical signs of skull fracture, GCS score of 13, 2 or more vomiting episodes, decreasing GCS score, or pedestrian struck by Annals of Emergency Medicine 1
Systematic Review Snapshot
Examination and Quality Assessment Tool for Diagnostic Accuracy Studies score. When data were available, sensitivity, specificity, likelihood ratios (LRs), and odds ratios with 95% confidence intervals were calculated for history and physical examination findings. The authors also assessed heterogeneity for summary measures that were included in 3 or more studies.
motor vehicle were variables identified as higher risk for intracranial injuries (Table 1). Among patients with negative clinical prediction rule application results, the risk of intracranial injury was decreased further (Canadian CT Head Rule LR–¼0.04, and the probability of severe injury was 0.31%; New Orleans Criteria LR–¼0.08, and the probability of severe injury was 0.61%) (Table 2).
Commentary Traumatic brain injury is the leading cause of death and disability in the United States, with up to 2.5 million patients presenting for medical evaluation after trauma annually.1,2 Neuroimaging such as computed tomography (CT) is indicated in patients with moderate (GCS score of 9 to 12) or severe (GCS score 8) head trauma. In patients with minor head injury (GCS score 13 to 15 and minimal or no altered mental status), the need for imaging is less certain. Although only 5% to 15% of patients with minor head injury will have intracranial injuries, cost and radiation risk make imaging all patients impractical.3 Acute care providers are expected to determine which patients require radiographic imaging in minor head injury. Concerning 2 Annals of Emergency Medicine
physical examination features— signs of skull fracture, vomiting more than once, declining GCS score, or pedestrian struck by vehicle—suggest that neuroimaging should be performed. Although these represent higherrisk signs and symptoms for detecting severe intracranial injury, many have LRs that would indicate moderate ability to predict these injuries, highlighting the challenges with consistently identifying high-risk patients. Applying a clinical decision rule after excluding these variables helps to identify low-risk patients who may not require radiographic imaging. However, whether to use the Canadian CT Head Rule (higher specificity, fewer negative CT results; LR 0.04, probability of severe injury 0.31%) or the New Orleans Criteria (LR 0.08; probability of severe injury 0.61%) is not conclusively addressed. The Canadian CT Head Rule included patients with GCS scores of 13 to 15, witnessed loss of consciousness, amnesia, or disorientation.4 A GCS score of 13 is considered by some to be higher risk for intracranial injury and may actually represent a In moderate head injury.4 contrast, the New Orleans Criteria included only patients with GCS score 15 and a loss of consciousness or amnesia.5 Use of radiographic imaging in the emergency department (ED) setting has been highlighted through national efforts in the Choosing Wisely campaign, thus attempting to reduce costs while improving patient care by “avoiding wasteful or unnecessary medical tests, treatments and procedures.”6 Although no individual history and physical examination feature can completely exclude
intracranial injury after minor trauma, the American College of Emergency Physicians recommends avoiding head CT scans in ED patients with minor head injury who are at low risk according to validated decision rules.6 A small number of patients may still have an intracranial injury even when clinical decision rule results are negative (although that risk is likely <1%). Determining the need for neuroimaging in patients with minor head trauma can be challenging. However, clinical decision rules, including the Canadian CT Head Rule and New Orleans Criteria, can be helpful in identifying patients at low risk for severe intracranial injury. Editor’s Note: This is a clinical synopsis, a regular feature of the Annals’ Systematic Review Snapshot (SRS) series. The source for this systematic review snapshot is: Easter JS, Haukoos JS, Meehan WP, et al. Will neuroimaging reveal a severe intracranial injury in this adult with minor head trauma? the rational clinical examination systematic review. JAMA. 2015;314:2672-2681. 1. Coronado VG, Xu L, Basavaraju SV, et al. Surveillance for traumatic brain injury–related deaths—United States, 19972007. MMWR Surveill Summ. 2011;60:1-32. 2. Marin JR, Weaver MD, Yealy DM, et al. Trends in visits for traumatic brain injury to emergency departments in the United States. JAMA. 2014;311:1917-1919. 3. Brenner DJ, Hall EJ. Computed tomography—an increasing source of radiation exposure. N Engl J Med. 2007;357:2277-2284. 4. Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet. 2001;357: 1391-1396. 5. Haydel MJ, Preston CA, Mills TJ, et al. Indications for computed tomography in patients with minor head injury. N Engl J Med. 2000;343:100-105. 6. Choosing Wisely. Available at: http://www. choosingwisely.org. Accessed January 20, 2016.
Michael Brown, MD, MSc, and Alan Jones, MD, serve as editors of the SRS series. Volume
-,
no.
-
:
-
2016
TAKE-HOME MESSAGE Negative results for Canadian CT Head Rule or New Orleans Criteria can identify patients with minor head trauma for whom routine neuroimaging is unlikely to identify a clinically significant intracranial injury (<1%). High-risk features should prompt providers to consider neuroimaging. Update: Do Patients With Minor Head Trauma Require Neuroimaging?
METHODS
EBEM Commentators
DATA SOURCES The authors performed a systematic search of MEDLINE and the Cochrane Library through August 2015 to identify studies assessing the diagnosis of traumatic intracranial injuries. The authors also reviewed articles in the authors’ files, article references, and textbook references for additional articles. STUDY SELECTION English-language studies with greater than 50% of the participants older than 18 years and with a minor head injury, defined as a Glasgow Coma Scale (GCS) score of 13 to 15, were included. All studies measured the performance of history and physical examination findings for identifying intracranial injury, with a reference standard of neuroimaging or follow-up evaluation. The authors defined intracranial injury a priori as any of the following: subdural, epidural, ventricular, or parenchymal hematoma; subarachnoid hemorrhage; herniation; or depressed skull fracture.
Melody Milliron, DO Jestin N. Carlson, MD, MS Department of Emergency Medicine Saint Vincent Hospital Erie, PA
Results Table 1. LRs of various risk factors, signs, and symptoms of patients with mild traumatic brain injury for severe intracranial injury. Characteristics
Volume
-,
no.
-
:
-
2016
LRD (95% CI)*
LR– (95% CI)*
2
3–4.3
0.87–0.93
3
3.6 (3.1–4.1)
0.76 (0.61–0.95)
3 5
16 (3.1–59) 6 (3.9–8)
0.85 (0.48–0.98) 0.84 (0.76–0.92)
2 3 3 2
3.4–16 3.5 (1.6–7.6) 4.9 (2.8–8.5) 1.9–7
0.76–0.8 0.63 (0.45–0.89) 0.88 (0.84–0.93) 0.91–0.96
Risk factors Mechanism of injury Pedestrian struck Symptoms Vomiting, >2 episodes Signs Skull fracture Any Basal GCS score Any decline <15 at 2 h Initial score 13 Focal neurologic deficit
LRþ, Positive LR; CI, confidence interval; LR–, negative LR. *Findings from 2 studies are reported as ranges. Findings from more than 3 studies are reported as summary measures with 95% CI.
Table 2. Accuracy of clinical decision rules for identifying severe intracranial injury in patients with mild traumatic brain injury and loss of consciousness, amnesia, or disorientation.
Rule
DATA EXTRACTION AND SYNTHESIS Three investigators independently assessed qualifying studies undergoing full-text review and assigned a Rational Clinical
No. of Studies
Canadian CT Head Rule New Orleans Criteria
No. of Studies
LRD (95% CI)
LR– (95% CI)
Probability of Severe Intracranial Injury if No Findings Present (95% CI)
5 5
1.6 (1.5–1.8) 1.1 (1.1–1.2)
0.04 (0–0.65) 0.08 (0.01–0.84)
0.31 (0–4.7) 0.61 (0.08–6)
Of 2,670 potential studies, the authors identified 14 meeting the inclusion criteria, which included a total of 23,079 patients with minor
head trauma. Clinical signs of skull fracture, GCS score of 13, 2 or more vomiting episodes, decreasing GCS score, or pedestrian struck by Annals of Emergency Medicine 1
Systematic Review Snapshot
Examination and Quality Assessment Tool for Diagnostic Accuracy Studies score. When data were available, sensitivity, specificity, likelihood ratios (LRs), and odds ratios with 95% confidence intervals were calculated for history and physical examination findings. The authors also assessed heterogeneity for summary measures that were included in 3 or more studies.
motor vehicle were variables identified as higher risk for intracranial injuries (Table 1). Among patients with negative clinical prediction rule application results, the risk of intracranial injury was decreased further (Canadian CT Head Rule LR–¼0.04, and the probability of severe injury was 0.31%; New Orleans Criteria LR–¼0.08, and the probability of severe injury was 0.61%) (Table 2).
Commentary Traumatic brain injury is the leading cause of death and disability in the United States, with up to 2.5 million patients presenting for medical evaluation after trauma annually.1,2 Neuroimaging such as computed tomography (CT) is indicated in patients with moderate (GCS score of 9 to 12) or severe (GCS score 8) head trauma. In patients with minor head injury (GCS score 13 to 15 and minimal or no altered mental status), the need for imaging is less certain. Although only 5% to 15% of patients with minor head injury will have intracranial injuries, cost and radiation risk make imaging all patients impractical.3 Acute care providers are expected to determine which patients require radiographic imaging in minor head injury. Concerning 2 Annals of Emergency Medicine
physical examination features— signs of skull fracture, vomiting more than once, declining GCS score, or pedestrian struck by vehicle—suggest that neuroimaging should be performed. Although these represent higherrisk signs and symptoms for detecting severe intracranial injury, many have LRs that would indicate moderate ability to predict these injuries, highlighting the challenges with consistently identifying high-risk patients. Applying a clinical decision rule after excluding these variables helps to identify low-risk patients who may not require radiographic imaging. However, whether to use the Canadian CT Head Rule (higher specificity, fewer negative CT results; LR 0.04, probability of severe injury 0.31%) or the New Orleans Criteria (LR 0.08; probability of severe injury 0.61%) is not conclusively addressed. The Canadian CT Head Rule included patients with GCS scores of 13 to 15, witnessed loss of consciousness, amnesia, or disorientation.4 A GCS score of 13 is considered by some to be higher risk for intracranial injury and may actually represent a In moderate head injury.4 contrast, the New Orleans Criteria included only patients with GCS score 15 and a loss of consciousness or amnesia.5 Use of radiographic imaging in the emergency department (ED) setting has been highlighted through national efforts in the Choosing Wisely campaign, thus attempting to reduce costs while improving patient care by “avoiding wasteful or unnecessary medical tests, treatments and procedures.”6 Although no individual history and physical examination feature can completely exclude
intracranial injury after minor trauma, the American College of Emergency Physicians recommends avoiding head CT scans in ED patients with minor head injury who are at low risk according to validated decision rules.6 A small number of patients may still have an intracranial injury even when clinical decision rule results are negative (although that risk is likely <1%). Determining the need for neuroimaging in patients with minor head trauma can be challenging. However, clinical decision rules, including the Canadian CT Head Rule and New Orleans Criteria, can be helpful in identifying patients at low risk for severe intracranial injury. Editor’s Note: This is a clinical synopsis, a regular feature of the Annals’ Systematic Review Snapshot (SRS) series. The source for this systematic review snapshot is: Easter JS, Haukoos JS, Meehan WP, et al. Will neuroimaging reveal a severe intracranial injury in this adult with minor head trauma? the rational clinical examination systematic review. JAMA. 2015;314:2672-2681. 1. Coronado VG, Xu L, Basavaraju SV, et al. Surveillance for traumatic brain injury–related deaths—United States, 19972007. MMWR Surveill Summ. 2011;60:1-32. 2. Marin JR, Weaver MD, Yealy DM, et al. Trends in visits for traumatic brain injury to emergency departments in the United States. JAMA. 2014;311:1917-1919. 3. Brenner DJ, Hall EJ. Computed tomography—an increasing source of radiation exposure. N Engl J Med. 2007;357:2277-2284. 4. Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet. 2001;357: 1391-1396. 5. Haydel MJ, Preston CA, Mills TJ, et al. Indications for computed tomography in patients with minor head injury. N Engl J Med. 2000;343:100-105. 6. Choosing Wisely. Available at: http://www. choosingwisely.org. Accessed January 20, 2016.
Michael Brown, MD, MSc, and Alan Jones, MD, serve as editors of the SRS series. Volume
-,
no.
-
:
-
2016