Each year, well over 1 million patients arrive at U.S. and Canadian emergency departments (EDs) for evaluation after blunt head trauma. About 20 percent of these patients have computed tomographic (CT) head scans. Of these patients, less than 2 percent have CT findings that are considered "therapeutically inconsequential," that is, would not lead to a poor outcome or the need for a neurological procedure, according to a new study. Yet the same study found that 12 percent of patients with therapeutically inconsequential CT findings nonetheless had important neurosurgical outcomes. An important neurosurgical outcome was defined as the performance of a directed intervention (craniotomy within 5 days of injury or intracranial pressure monitoring) or a poor neurologic outcome (Glasgow Coma Score of 1, death; 2, persistent vegetative state; or 3, severe disability).
Because poor outcomes can occur in the presence of a normal CT scan result, the researchers sought to determine whether the patients with an important neurosurgical outcome could have been identified clinically. They found that two clinical indicators were predictive of a poor outcome: abnormal mental status and/or abnormal coagulation. Of the nine patients for whom followup data were available, all had abnormal mental status on admission (Glasgow Coma Scale score less than 15 indicating problems such as delayed response to stimuli, disorientation, memory problems, or excessive sleepiness). Also abnormal coagulation (often sparked by traumatic injury) was present in five of the seven patients for whom coagulation status was known.
Emergency practice should not be changed on the basis of this small number of patients, but these findings do suggest the need for extra caution in patients with head injuries who have one of these clinical findings, regardless of CT findings thought to be inconsequential, notes William R. Mower, M.D., Ph.D., of the University of California-Los Angeles School of Medicine.
For the study, which was supported in part by the Agency for Healthcare Research and Quality (HS09699), the researchers enrolled all blunt head trauma patients undergoing emergency head CT imaging at 18 centers participating in the National Emergency X-radiography Utilization Study II (NEXUS). From these cases, they identified patients seen at six sites whose official CT reading met the criteria for "therapeutically inconsequential" injuries.
See "Defining therapeutically inconsequential head computed tomographic findings in patients with blunt head trauma," by Clare Atzema, M.D., Dr. Mower, Jerome R. Hoffman, M.A., M.D., and others, in the July 2004 Annals of Emergency Medicine 44(1), pp. 47-56.