HYDROCEPHALUS REQUIRING TREATMENT AS A SE QUEL OF CEREBRAL RADIATION

Cerebral atrophy is a well known consequence of external beam irradiat ion for brain tumour therapy. However, it is much less known that a co mmunicating hydrocephalus may also be a sequel of cerebral irradiation . In the last nine years we treated three patients suffering from symp toms of a so-called, ''normal pressure hydrocephalus'' which occurred one to three years after external cerebral beam irradiation. Because o f the clinical and radiological similarity of these patients and those suffering from a brain atrophy, a sophisticated diagnostic procedure was necessary. We performed ICP monitoring for three days, CSF dynamic tests and in 2 cases CBF evaluation by xenon CCT before and after lum bar puncture. The results of these examinations allowed a clear differ entiation from atrophic conditions. All patients received a Hakim high -high pressure value (range 160-180 mm/Hg) and had a favourable clinic al course after the operation. In our opinion the hydrocephalus in the se patients was induced by the cerebral irradiation, other causes (hyp er-, paraproteinemia in the CSF, meningeal spread of the tumour for ex ample) could be excluded. The aetiology of the hydrocephalus may be an irradiation-induced damage to the CSF resorption sites or radiation-i nduced leptomeningeal reactions leading to an obstruction of the subar achnoidal space.