Post-traumatic Normal Pressure Hydrocephalus following Severe Head Injury

Six cases of normal perssure hydrocephalus (NPH) were found among 160 surgical cases of intracranial hematoma due to severe head injury, in the past 10 years. Out of the 160 cases, 80 were followed up. The incidence of post-traumatic NPH was 3.7%, or 7.5% in the followed-up cases. After a little improvement following the removal of intracranial hematoma, these cases showed prolonged disturbance of consciousness or a delayed recovery rate and a progressive enlargement of the ventricle without cerebral atrophy on CT scan. Diagnosis of post-traumatic NPH was made by the plateau level of clinical improvement accompanied by absence of intracranial hypertension and a progressive ventricular dilatation shown by an increased bicaudate cerebroventricular index on CT scan. Radioisotope serum albumin cisternography revealed disturbance of cerebrospinal fluid (CSF) circulation in all these cases and was a reliable tool for determining the indication for a shunting operation, which brought a marked improvement in five patients. The authors believe that the shunting operation should be tried on post-traumatic NPH patients who do not show cerebral atrophy. Presence of a subarachnoidal and a contusional hemorrhage on brain surfaces, noted in the operation, suggests the need to pay attention not only to the disturbance of the conventional extracerebral CSF pathway, but to that of the intracerebral pathway as regards the pathogenesis of post-traumatic NPH.