Prospective study of validity of neurologic signs in predicting positive cranial computed tomography following minor head trauma.

INTRODUCTION: The ability to discriminate among a large number of patients with mild head injury to detect those most likely to have an intracranial abnormality may offer an advantage in mass-casualty situations and when clinical needs exceed diagnostic capabilities.

HYPOTHESIS: In patients with mild head injury (Glasgow Coma Scale score = 13-15), the likelihood of intracranial abnormality, as defined by cranial computed tomography (CT), varies according to presenting neurologic signs and symptoms.

METHODS: This prospective study consisted of 152 patients with blunt head trauma and one or more of the following: initial loss of consciousness (LOC), headache, vomiting, convulsions, or amnesia. All underwent cranial CT within one hour of presentation. Positive CT findings were defined as cerebral contusion, extra-axial hematoma, intra-ventricular or subarachnoid hemorrhage, brain edema, and skull fracture. Clinical findings were tabulated and compared with CT findings.

RESULTS: The most common symptoms were headache (61%) followed by followed by LOC (45%), vomiting (39%), amnesia (29%), and convulsions (4%). Convulsions were the most predictive of a CT positive finding (80%); history of LOC was least predictive (29%). The presence of two or more clinical findings tended to increase the likelihood of intracranial abnormality, but the association was neither consistent nor additive.

CONCLUSIONS: Convulsions occurring in a patient with mild head injury are highly predictive of a positive intracranial finding on CT. Headache, amnesia, and vomiting are each likely to show positive findings in approximately 40-45% of cases. Although the least predictive of the neurologic findings studied, loss of consciousness still correlates with a positive cranial CT in 29% of cases. More than one sign or symptom increases the likelihood of concurrent brain injury.