Haemodialysis and cerebral oedema

Background: Haemodialysis may cause neurological symptoms ranging from inco nvenient feelings of disequilibrium to life-threatening neurological compli cations. There are animal data to suggest cerebral swelling may accompany h aemodialysis and contribute symptomatically to dialysis disequilibrium. How ever, MR images acquired following haemodialysis often fail to demonstrate evidence of cerebral oedema. We wished to quantify any potential cerebral v olume change which is caused by haemodialysis treatment. Method: Five renal patients and 5 control subjects had a two volumetric T1-weighted MRI scans on the same day. The patients were imaged immediately before and after hae modialysis. None were taking steroids. Precise positional matching (registr ation) was used to quantify cerebral volume change. Results: Patients had a n increase in cerebral volume following dialysis which averaged 32.8 ml (SE 7.4 ml, 3% brain volume). The change in the controls was 1.4 ml (SE 0.6 ml ), p < 0.001. No patient had significant neurological symptoms. Conclusion: Cerebral oedema developed in the patients following dialysis. There is a g ood biological model for these observations. Modifications to dialysis may help. Common problems which increase cerebral volume, e.g, acute stroke, re quire careful appraisal in these patients. These observations need consider ation when quantifying atrophy in dialysis patients. Copyright (C) 2001 S. Karger AG, Basel.