Journal of Emergencies, Trauma, and Shock

ORIGINAL ARTICLE
Year
: 2011  |  Volume : 4  |  Issue : 4  |  Page : 472--476

Indications for brain computed tomography scan after minor head injury


Mahdi Sharif-Alhoseini1, Hossein Khodadadi2, Mojtaba Chardoli2, Vafa Rahimi-Movaghar3,  
1 Department of Neurosurgery, Sina Trauma and Surgery Research Center, Tehran, Iran
2 Department of Emergency, Hazrat-e-Rasool Hospital, Tehran University of Medical Sciences, Tehran, Iran
3 Department of Neurosurgery, Sina Trauma and Surgery Research Center, Tehran; Research Centre for Neural Repair, University of Tehran, Tehran, Iran

Correspondence Address:
Vafa Rahimi-Movaghar
Department of Neurosurgery, Sina Trauma and Surgery Research Center, Tehran; Research Centre for Neural Repair, University of Tehran, Tehran
Iran

Abstract

Aims : Minor head injury (MHI) is a common injury seen in Emergency Departments (ED). Computed tomography (CT) scan of the brain is a good method of investigation to diagnose intracranial lesions, but there is a disagreement about indications in MHI patients. We surveyed the post-traumatic symptoms, signs or past historical matters that can be used for the indication of brain CT scan. Materials and Methods : All patients with MHI who were older than 2 years, had a Glasgow Coma Scale (GCS) score ≥13 and were referred to the ED, underwent brain CT scan. Data on age, headache, vomiting, loss of consciousness (LOC) or amnesia, post-traumatic seizure, physical evidence of trauma above the clavicles, alcohol intoxication, and anticoagulant usage were collected. The main outcome measure was the presence of lesions related to the trauma in brain CT scan. For categorical variables, Chi-square test was used. Results : Six hundred and forty-two patients were examined by brain CT scan after MHI, and 388 patients (60.4%) did not have any risk indicator. Twenty patients (3.1%) had abnormal brain CT scans. The logistic regression model showed that headache (P=0.006), LOC or amnesia (P=0.024) and alcohol (P=0.036) were associated with abnormal brain CT. Conclusions : We suggested that abnormal brain CT scan related to the trauma after MHI can be predicted by the presence of one or more of the following risk indicators: Headache, vomiting, LOC or amnesia, and alcohol intoxication. Thus, if any patient has these indicators following MHI, he must be considered as a high-risk MHI.



How to cite this article:
Sharif-Alhoseini M, Khodadadi H, Chardoli M, Rahimi-Movaghar V. Indications for brain computed tomography scan after minor head injury.J Emerg Trauma Shock 2011;4:472-476


How to cite this URL:
Sharif-Alhoseini M, Khodadadi H, Chardoli M, Rahimi-Movaghar V. Indications for brain computed tomography scan after minor head injury. J Emerg Trauma Shock [serial online] 2011 [cited 2019 Dec 8 ];4:472-476
Available from: http://www.onlinejets.org/text.asp?2011/4/4/472/86631


Full Text

 Introduction



Minor head injury (MHI) is one of the most common injuries seen in Emergency Departments (ED), [1] which has typically been defined as patients with a history of blunt head trauma who present findings of a Glasgow Coma Scale (GCS) score of 13-15 on initial ED evaluation. [2] The brain computed tomography (CT) scan is a good investigation method to diagnose intracranial lesions. [3] Indications for CT scan might be different based on the main outcome measures, which could be the presence of any abnormal lesion in CT scan related to the trauma [4],[5],[6] or presence of lesions suggested by a surgical operation. [7] But because of the cost, [8] time, and probable complications of radiation, [9] there has been significant disagreement about the indications for brain CT scan in the large number of MHI cases. [10]

Symptoms such as headache, [5] vomiting, [11] loss of consciousness (LOC) or amnesia, [12] and post-traumatic seizure [13] signs such as physical evidence of trauma above the clavicles, [6] skull fracture or contusion [7],[11],[13] and raccoon sign, [14] past history such as alcohol intoxication [12] or coagulopathy, [15] and age more than 60 years [16] have been discussed as the risk indicators for abnormalities in brain CT scan of patients with MHI. Thus, several studies have been performed to determine variables for brain CT indication. [4],[7],[17],[18],[19],[2]0,[21] However, no general consensus has been achieved in the indications for brain CT scan. This study was conducted to survey the post-traumatic symptoms, signs or other important past historical matters of patients as a risk indicator that can be used for the indication of brain CT scan in the MHI.

 Materials and Methods



In this prospective study, all patients with blunt traumatic head injury who were more than 2 years old, had a GCS score ≥13 and were referred to the EDs of Rasoul-Akram and Shohadaye-Haftome-Tir hospitals (two referral trauma centers in Tehran) in 2008, underwent non-contrast brain CT scan. They were scanned on similar CT scanners with the same techniques at both hospitals. The patients were primarily visited by residents of Emergency Medicine. Data on age, headache, vomiting, LOC or amnesia, post traumatic seizure, physical evidence of trauma above the clavicles, alcohol intoxication and current anticoagulant usage were collected. The risk indicators were defined based on Haydel's study: [6] Headache was defined as any new head pain, whether diffused or local. Vomiting was defined as any emesis after a traumatic occurrence. A deficit in short-term memory was defined as persistent anterograde amnesia in a patient with an otherwise normal score on the GCS. The reliability of obtaining a history of loss of consciousness and post-traumatic amnesia is a difficult and well-known problem in clinical practice, and therefore both of them were our practical definition. Seizure was defined as a suspected or witnessed seizure after the traumatic event. The physical evidence of trauma above the clavicles was defined as any external evidence of injury, including contusions, abrasions, lacerations, deformities, and signs of facial or skull fracture. Alcohol intoxication was determined on the basis of the history obtained from the patient or a witness and suggestive findings such as slurred speech or the odor of alcohol on the breath on physical examination. Coagulopathy was defined as a history of bleeding or a clotting disorder or current treatment with warfarin or other types of anticoagulation.

Instability, additional troubles that required specialized care, opium-addiction, probability of malingering, and refusing to take part in the study; factors which excluded the patients from the study. All questionnaires and clinical assessments were completed before the brain CT studies; therefore, the evaluating clinician was blind to the result of scanning.

Brain CT scans were reviewed by the attending physician at the ED who had 5 years of experience. The main outcome measured was the presence of lesions related to the trauma in brain CT scan, which includes depressed fracture, base skull fracture, epidural hematoma, subdural hematoma, subarachnoid hemorrhage, pneumocephalus, and contusion.

The hospitalized patients were visited daily by residents of Emergency Medicine and the other patients were followed-up after one week using telephone interviews to assess for symptoms of increased intracranial pressure.

The frequency of positive CT scans was determined for each risk indicator. The sensitivity, specificity, and positive and negative predictive values of significant indicators were calculated for those risk indicators, which had an association with abnormal brain CT scan related to the trauma. For categorical variables, Chi-square test was used. Predictive analytics software (PASW) version18 was utilized for analyzing the data. Logistic regression analysis was performed using STATA 8, (Special Edition, Texas, USA) to detect the risk indicators associated with positive findings in the brain CT scan controlling the effect of other risk indicators.

The study was reviewed and confirmed by the Ethics Committee of the Iran University of Medical Sciences.

 Results



Six hundred and forty-two patients were examined by brain CT scan after a blunt head trauma. The mean age of the patients was 29.9±16.7 years (range: 3 to 90), and 74.5% were male. Three hundred eighty-eight patients (60.4%) did not have any risk indicator [Table 1]. The number of risk indicators was associated with a higher rate of abnormal finding related to the trauma in CT scans [Table 1].{Table 1}

Twenty patients (3.1%) had abnormal brain CT scans. Among the patients with abnormal brain CT related to the trauma, one had no risk indicators, all of the remaining had LOC or amnesia; thirteen patients had two risk indicators, and six people had three indicators at the same time. Patients with headache, LOC or amnesia, and vomiting had a higher rate of abnormal CT scans [Table 2]. A schematic illustration of the sensitivity and specificity of different symptoms and signs in mild head injury was shown in [Figure 1].{Table 2}{Figure 1}

Finally, the regression analyses were applied to determine the effects of variables associated with abnormal brain CT scan related to the trauma. The logistic regression model showed that headache (P=0.006), LOC or amnesia (P=0.024), and alcohol (P=0.036) were associated with abnormal brain CT related to the trauma [Table 3].{Table 3}

 Discussion



This study demonstrated that headache, vomiting, LOC or amnesia, and alcohol intoxication were four risk indicators suggested for the indication of brain CT scan in MHI.

Hydel et al., [6] and Miller et al., [5] showed that headache could be used as a guide to predict the probability of abnormal brain CT scan related to the trauma following MHI. Mack and colleagues proved that headache is a low-risk predictor. [2] But some studies did not lead to similar results and showed that headache could not be used as a risk indicator. [4],[7],[21],[22]

Several studies have reported vomiting as a post-traumatic symptom, which predicts abnormality related to the trauma in brain CT scan, but Viola et al. said that vomiting was insignificant. [23]

Based on some researches, LOC or amnesia could be used as a guide to predict the probability of abnormal CT scan following MHI. [6],[14],[24] Murshid et al. [25] and Gomez et al. [26] found the converse result.

Alcohol intoxication had been demonstrated as a risk predictor in the investigations of Hydel et al. [6] and Reinus et al., [12] but other reports said that alcohol usage could not be a predictor sign. [2],[4],[14]

In our study, only 3.2% of the patients with MHI had positive findings related to the trauma in brain CT scan. The same result was seen in other studies, i.e., abnormal CT was seen in about less than 10 percent of the patients with MHI and less than 1% of all patients with MHI requiring neurosurgical intervention. [11] The rate of brain CT abnormality was seen in 3% to 13% of the patients with GCS score 15 and LOC or amnesia and 4.9% to 6.3% in patients with GCS 15 and without LOC or amnesia. [9]

In our study, the presence of headache, vomiting, and LOC or amnesia was separately associated with abnormal brain CT scan related to the trauma. Stein et al. suggested that any patient who has experienced LOC or amnesia following head injury should undergo brain CT scan. [27] Haydel et al. have expanded the criteria for brain CT scan in patients with MHI that consist of headache, vomiting, age >60 years, drug or alcohol intoxication, deficits in short-term memory, physical evidence of trauma above the clavicles, and seizure. These criteria led to a sensitivity of 100% and a specificity of 25%. [6]

Miller et al. planned the application of severe headache, nausea, vomiting, and depressed skull fracture on physical examination to identify patients with MHI, which led to a 61% decline in brain CT scan. [11]

Both Miller and Hydel's criteria were developed for patients with GCS 15, while our study included patients with GCS 13-15.

We demonstrated that each combination of age >60 and headache, headache and vomiting, and headache and trauma above the clavicles led to a significantly higher rate of abnormal brain CT scans [Table 2]. Several studies have evaluated various combinations of clinical findings as predictors of positive brain CT scans in patients with MHI. [5]

In our study, all of the patients with positive brain CT scans had at least one risk indicator. Saadat et al. showed that the brain CT scans were always normal in patients <65 years old who did not have an obvious head wound, a raccoon sign, vomiting, memory deficit, or a decrease in their GCS score. [14]

Stiell et al. have developed the Canadian CT head rule consisting of 5 high-risk criteria including age >65 years, suspected open or depressed skull fracture, vomiting more than two episodes, sign of basal skull fracture and GCS score <15 at 2 hours after trauma that suggest the risk of neurological intervention and 2 medium-risk criteria including amnesia before impact >30 minutes and dangerous mechanism of injury that suggest the risk of significant brain injury on brain CT scan. [7] Using these criteria, 46% of the patients would not need to undergo CT scanning. In this rule, patients without LOC, amnesia or disorientation were not evaluated in the study, but we included all patients with a history of blunt head trauma.

Smith et al. have reported that the Canadian CT head rule has a lower sensitivity than Hydel's criteria for CT, but would recognize all patients necessitating neurosurgical intervention, and has a greater potential for reducing brain CT scan. [28] A larger patient sample could increase the possibility of detecting other neurological signs and indicators in patients with MHI and result in a better predictive power of the model. [14]

 Conclusions



We suggested that abnormal brain CT scan related to the trauma after MHI can be predicted by the presence of one or more of the following risk indicators: Headache, vomiting, LOC or amnesia and alcohol intoxication. Thus, if any patient has these indicators following MHI, he must be considered a high-risk MHI.

 Acknowledgement



The authors thank Mrs. Bita Pourmand for her edit of the manuscript.

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