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.