Indications for Computed Tomography in Older Adult Patients With Minor Head Injury in the Emergency Department

Abstract

Older age is a risk factor for intracranial injury after head trauma, and computed tomography (CT) is generally recommended. We aimed to develop a clinical prediction rule for risk stratification to avoid CT head imaging in older adult patients with minor head injury, named Computed Tomography of the Head for the patients at Advanced age (CTHEAD). This was a single-center observational study in Japan that used retrospective chart review data to service a prediction rule that was prospectively validated. Patients aged ≥ 65 years who presented to our emergency department with a chief complaint of head trauma and a Glasgow Coma Scale (GCS) of ≥13 were eligible. Patients were excluded if they had GCS score < 13, anticoagulant therapy, focal neurologic symptoms, posttraumatic seizures, penetrating injury, evident depressed fracture, unknown mechanism, or CT not undertaken. The primary outcome was acute traumatic lesion on head CT. We screened 1,494 patients; 538 were included in the derivation cohort, and 580, in the validation cohort. Multivariable analysis of the derivation group found that high-risk mechanisms of injury, vomiting, witnessed loss of consciousness, and anterograde amnesia were significantly associated with traumatic head findings on CT. A clinical prediction rule was developed from these four risk factors. The negative predictive value (NPV) of the absence of the four components was 95.1% (95% confidence interval [CI] = 92.9% to 96.7%), and the positive predictive value (PPV) of one or more risk factors was 20.6% (95% CI = 17.3% to 24.4%). The rule was validated prospectively with an NPV of zero risk factors of 94.5% (95% CI = 92.4% to 96.1%) and a PPV of one or more risk factors of 15.9% (95% CI = 13.0% to 19.3%). Fifty-three (9.1%) patients in the validation cohort experienced the primary outcome. The results suggest that older adult patients with minor head injury may forgo head CT if they do not have high-risk mechanisms of injury, vomiting, witnessed loss of consciousness, or anterograde amnesia. External validation of this rule is needed.