CORPUS CALLOSAL CHANGES ASSOCIATED WITH HYDROCEPHALUS - A REPORT OF 2CASES

OBJECTIVE AND IMPORTANCE: Focal or diffuse corpus callosal changes can occur in patients with active hydrocephalus who undergo shunting proc edures. The neural compression caused by active hydrocephalus and the conditions that follow ventricular shunting may contribute to the deve lopment of these changes. CLINICAL PRESENTATION: Two patients who unde rwent successful shunting for hydrocephalus subsequently developed thi ckening and diffuse signal changes in the corpus callosum, which were revealed by magnetic resonance imaging. The abnormal signal intensity extended laterally and linearly along the callosal fiber tracts and wa s not associated with mass effect. These changes persisted despite cli nical improvement after the shunts were implanted. INTERVENTION: Detai led neuropsychological testing showed no evidence of residual cognitiv e impairment or any interruption of the interhemispheric transfer of i nformation. It has been proposed that the impingement of the corpus ca llosum by the rigid fair may contribute to symptomatic hydrocephalus. Impingement may cause partial hemispheric disconnection, resulting fro m callosal axonal dysfunction. Our patients showed radiographic eviden ce of dramatic changes within the corpus callosum after ventricular sh unting, consistent with a transcallosal demyelinating process. Patient s demonstrated neither clinical nor neuropsychological evidence of cal losal disconnection, even though the callosal changes persisted. In th ese two patients, it is reasonable to assume that the relative sparing of the splenium accounts for the lack of neuropsychological deficits. CONCLUSION: Based on our findings, conservative management, rather th an a stereotactic biopsy or other forms of intervention, seems reasona ble when these characteristic changes of the callosum are noted by mag netic resonance imaging after a shunt for hydrocephalus has been impla nted in the patient.