Classification of Computerized Tomography and Prognosis of Traumatic Primary Brain Stem Injury

Abstract

Clinical signs, computerized tomography (CT), continuous monitoring of intracranial pressure (ICP), serial recording of auditory brain stem response (ABR), and autopsy were examined in 40 cases of primary brain stem injury (PBSI) which showed clinical symptoms of prolonged coma, abnormal motor responses (decorticate, decerebrate or flaccid), impaired oculocephalic and/or pupillary responses, and no evidence of focal mass lesions on initial CT scanned within 2 hours after the injury. The consciousness levels of the 40 cases of PBSI on admission were 5 or less by the Glasgow Coma Scale; 5 in 12 cases; 4 in 15 cases; 3 in 13 cases. CT findings of the brain stem region (mesencephalon, pons, and medulla oblongata) of PBSI were classified into 7 types: brain stem hemorrhage (Type I); IVth ventricle hemorrhage (Type II); subarachnoid hemorrhage in the basal cisterns (Type III); compressed basal cisterns (Type IV); pneumocephalus in the basal cisterns (Type V); combined abnormal findings in the brain stem regions (Type VI); no abnormal findings in the brain stem regions (Type VII). Those cases of PBSI with initial CT findings of Type I, Type II, Type III, Type V, and Type VI all died. On the other hand, 7 cases of PBSI (17.5%) demonstrating good recovery or moderate disability by the Glasgow Outcome Scale (6 months after injury) were of Type IV (mortality 66.7%) and Type VII (mortality 50%); 5 of these cases (71.5%) were children. It has become obvious that there are many types of CT findings in PBSI besides brain stem hemorrhage that continuous ICP monitoring is very important to protect against secondary brain damage caused by increased ICP and that serial ABR recording predicts the outcome of PBSI very well as it provides reliable information about the function of the brain stem.