Objective :To investigate the reasons of deterioration from an alert state for head injury patients and work out the best diagnosis and treatment method. Methods: Retrospectively analyze CT and clinical findings of 96 patients with head injuries who were alert and then deteriorated. Results: 63. 5% of patients who went from an alert to a deteriorated state showed acute variant of in-tracranial hematomas and edema; 14.6% of patients revealed subacute delayed hematomas and expansion of hematomas;and 21.9% revealed chronic subdural hematomas. Conclusion :The primary coma is not the only standard to judge whether there are primary brain injuries resulting from minor head injuries. We should observe alert head injury patients carefully

record GCS regularly and take head X - rays routinely. CT scanning can provide details and accurate information for us to evaluate minor or severe brain injury and risk. Further we should prevent and treat primary and secondary diseases which may cause deterioration. On conclusion

the above measures are keys to reduce mortality and disability of alert head injury patients.