Conversion of Communicating Hydrocephalus to Stenosis or Occlusion of the Aqueduct during Ventricular Shunt

Abstract

M ULTIPLE causes of hydrocephalus have long been recognized, ~,5,6,9,12 and the importance of recognizing the etiology in any individual case has been emphasized. 5 Whereas 2 obstruct ive lesions in the cerehrospinal fluid (CSF) sys tem have been demons t ra ted in single cases of hydrocephalus, reports of patients in whom the site of the CSF obstruct ion has shifted during t r e a t m e n t (shunting operation) are rare. 4 In our chronic care program involving a b o u t 200 hydrocephal ic children, periodic evaluat ions have been carried out over the pas t 7 years in an effort to determine the efficacy of the ventriculo-atrial shunt in the control of hydrocephalus as well as to assess the intellectual capaci ty of hydrocephalic children in whom the process has been held in abeyance by chronic shunting of the CSF. A va r i e ty of complications of this prolonged t r e a t m e n t have occurred; on occasion recur ren t septicemia has necessitated rem o v a l of the ventriculo-atrial shunt. In 1 of these cases fractional air s tudy demons t r a t ed only large ventricles; because the original diagnosis had been communicat ing hydrocephalus , a lumbar subarachnoid to u re te r CSF shunt was established. The resul t was nearly fatal . Within 48 hours the re were signs of brain herniation a t the ten tor ia l no tch and a t the cisterna magna. Quick review of the films showed tha t the child no longer had a communicat ing hydrocephalus but ra ther an aqueductal occlusion, d e m o n s t r a t e d on the pneumoencephalogram b u t not correct ly interpreted on the first reading. I m m e d i a t e revision to a ventriculo-