CT Scanning for Minor Head Injury
Abstract & Commentary
Synopsis: This study indicates a sensitive set of clinical indicators for obtaining a brain CT in patients with minor head trauma: headache, vomiting, age older than 60 years, drug or alcohol intoxication, deficits in short-term memory, physical evidence of trauma above the clavicles, and seizure.
Source: Haydel MJ, et al. N Engl J Med 2000;343:100-105.
Since the introduction of ct for evaluation of patients with potential head injury, selection of which patients should receive a CT scan remains controversial. While there is no question of use of CT in patients with major head injury, criteria for its use for screening patients with minor head injury have been variable. Approximately two-thirds of the patients with head trauma are classified as having minor head trauma and less than 10% of patients with minor head trauma have positive findings on CT scanning. The study in this report was undertaken to develop and validate a simple set of clinical criteria to use in identifying patients with minor head injury who should undergo CT.
Phase 1 consisted of 520 consecutive patients with minor head injury, who were at least 3 years old and presented within 24 hours of injury; were evaluated to determine which clinical findings identified patients with positive findings on CT of the head. Phase 2 consisted of application of the predictive findings of Phase 1 to a group of 909 patients with minor head injury. The predictive value of the findings in Phase 1 was prospectively validated in the Phase 2 questionnaire. Patients were studied in two groups: those who had at least one of the seven findings established in Phase 1 and those who had none. The frequency of positive CT scans was determined for each group. The sensitivity, specificity, and negative predictive value of the criteria were calculated.
The results of Phase 1 showed 6.9% positive CT scans. This finding is consistent with the results of other studies. All of the patients with positive CT scans had one or more of seven findings:
• Age older than 60 years
• Drug or alcohol intoxication
• Deficits in short-term memory
• Physical evidence of trauma to the head or neck
Of the 909 patients in Phase 2, 6.3% had positive scans. The combined sensitivity of the seven findings above, was 100% (95% confidence interval, 95-100%). All the patients with positive CT scans had at least one of the findings. The results suggest that of patients with minor head injury, those selected for CT should be those with one or more of the clinical findings noted.
Comment by Beverly P. Wood, MD, MSC
Routine use of head CT for all patients with minor head trauma is generally considered to be a waste of resources; however, identifying those who may be at risk from minor trauma is difficult. Some previous studies have evaluated predictors of positive CT scans, but the sensitivity has been below 100%. The use of skull radiographs to detect a fracture, soft tissue injury, and neurologic abnormalities have not proved to be accurate predictors of positive CT scans.
This study with a large number of consecutive patients relied on a symptom questionnaire to gather clinical data. The correlation with CT sensitivity is excellent. Phase 2 was undertaken to search for false- negative presentations. Reliance mainly on symptomatology also allows more expeditious patient workup without the need to await a detailed neurologic examination. Correlation of these selection criteria in other corroborating studies will be helpful in management of this large group of patients with minor trauma who may develop significant problems related to unanticipated central nervous system trauma.
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