A history of loss of consciousness or post-traumatic amnesia in minor head injury: "conditio sine qua non" or one of the risk factors?

Abstract

Objective: A history of loss of consciousness (LOC) or post-traumatic amnesia (PTA) is commonly considered a prerequisite for minor head injury (MHI), although neurocranial complications also occur when LOC/PTA are absent, particularly in the presence of other risk factors. The purpose of this study was to evaluate whether known risk factors for complications after MHI in the absence of LOC/PTA have the same predictive value as when LOC/PTA are present. Methods: A prospective multicentre study was performed in four university hospitals between February 2002 and August 2004 of consecutive blunt head injury patients (>16 years) presenting with a normal level of consciousness and a risk factor. Outcome measures were any neurocranial traumatic CT finding and neurosurgical intervention. Common odds ratios (OR) were estimated for each of the risk factors and tested for homogeneity. Results: 2462 patients were included: 1708 with and 754 without LOC/PTA. Neurocranial traumatic findings on CT were present in 7.5% and were more common when LOC/PTA was present (8.7%). Neurosurgical intervention was required in 0.4%, irrespective of the presence of LOC/PTA. ORs were comparable across the two subgroups (p.0.05), except for clinical evidence of a skull fracture, with high ORs both when LOC/PTA was present (OR = 37, 95% CI 17 to 80) or absent (OR = 6.9, 95% CI 1.8 to 27). LOC and PTA had significant ORs of 1.9 (95% CI 1.0 to 2.7) and 1.7 (95% CI 1.3 to 2.3), respectively. Conclusion: Known risk factors have comparable ORs in MHI patients with or without LOC or PTA. MHI patients without LOC or PTA need to be explicitly considered in clinical guidelines.H ead injury is one of the most common injuries seen in emergency departments, minor head injury (MHI) accounting for 90-95% of cases.

A retrospective cohort study to re-evaluate clinical correlates for intracranial injury in minor head injury

“…The RR ratio for headache increased for the no LOC/PTA subgroup compared with the LOC/PTA subgroup but not when compared with the whole group. These findings concur with those of Smits et al ,7 namely that common clinical correlates may be important markers for intracranial abnormality on CT in the cohort of patients without LOC or PTA.…”

“…The addition of other clinical correlates (eg, vomiting, nausea or headache) in patients with LOC or PTA should in theory increase the sensitivity of identifying GCS 15 patients with traumatic CT abnormalities. This assumption was tested by Smits et al 7 in a multicentre prospective study that enrolled 2462 patients. One thousand seven hundred and eight patients had either LOC or PTA, 754 patients had neither.…”

Late presentations of minor head injury

“…Open or depressed skull fracture (0.2%; CI <0.0001% to 1.25%; p=0.0221) has been found to be highly significant by other studies (p<0.0001); however, few skull fractures were found in our study population (one patient only; 0.2%; CI <0.0001% to 1.25%) 5 23…”

Incidence of Traumatic Brain Injury Across the Full Disease Spectrum

“…16,20,21,45,55 Many investigations, including some earlier Rochester Epidemiology Project studies, required evidence of at least minimal loss of consciousness or post-traumatic amnesia to qualify as a case. 30,31,35,56 The requirement minimizes the proportion of false-positive cases that some authors caution can occur because symptoms following head injury are inflated by patient expectations or comorbid stress.…”

“…23,24,27 In light of increasing evidence of adverse outcomes following symptomatic events, the large numbers reported here also substantiate heightened concerns in the press and literature regarding implications, both at the individual and population level. 21,58 …”