Mild head injury: revisited.

OBJECTIVE: 1. To define the incidence of positive CT scans in patients with different grades of mild head injury (MHI), 2. To identify clinical predictors of positive CT scans, 3. To evaluate the usefulness of plain radiographs in the triage of patients with MHI, 4. To evaluate frequency and nature of surgical intervention in MHI, 5. To evaluate the risk of deterioration in MHI, and 6. To find out whether patients with normal neurological examination and normal CT can be safely discharged.
METHODS: In a prospective study conducted over a period of four months in our center, all patients with mild head injury (defined as Glasgow Coma Scores (GCS) 13-15) were admitted to the head injury unit. Patients underwent standard clinical examination, skull radiography and cranial CT. No clinical criteria were used to select patients for CT scanning and all the patients were subjected to CT. Patients with negative findings on CT and a normal neurological examination were discharged after 24 hours of observation. Patients with positive findings on cranial CT were treated either medically or surgically as deemed necessary. Outcome measures included safe discharge, clinical deterioration, need for surgical intervention or death. The following factors were analyzed statistically to find out whether they can be used as predictive factors for positive cranial CT. They were: age, sex, mode of injury, loss of consciousness, post-traumatic seizures, ear/ nose/throat bleeding, vomiting, admission GCS score, scalp injury, polytrauma, focal neurological deficit, fractures visualized on skull radiography.
RESULTS: Three hundred and eighty one patients were included in the study. Of these males constituted 63%, females 17% and children 20%. RTA was the most common mode of injury. Seventy five percent of the patients had GCS of 15, 15% had GCS of 14 and 10% had GCS of 13. Thirty eight percent of the patients had positive findings on the CT. Age, mode of injury, loss of consciousness, post-traumatic seizures, ENT bleeding, vomiting, scalp injury and polytrauma were not found to be predictors of positive CT. Admission GCS score, focal neurological deficits, and fractures detected by skull radiography were found to be statistically significant predictors of positive findings on CT. Seven percent of patients required surgical intervention. Six percent of patients showed neurological deterioration and there was one death in this series of MHI patients. Patients with multiple lesions on CT had a higher chance of deterioration than those with a single lesion. No patient who had a GCS of 15 and normal CT developed any complication during the hospital stay or after discharge.
CONCLUSIONS: The incidence of positive CT scans in this prospective, consecutive, unselected cohort of MHI patients was 38%. Lower admission GCS scores, focal neurological deficits, and fractures detected by skull x-rays were found to be significant predictors of positive CT. Other clinical parameters were not found to be predictors of positive CT. CT was found to be superior to plain x-rays in detecting skull fractures. Seven percent of this cohort required neurosurgical intervention. Six percent showed neurological deterioration and there was one death in this series. Patients with multiple lesions on CT had a higher chance of deterioration than those with single lesions. The duration of hospital stay was prolonged in patients with positive CT. As no patient with a normal neurological examination and a normal CT deteriorated, we believe these patients can be safely discharged without need for admission and observation.