Aluminium bone deposits in normal renal function patients after long-term treatment by plasma exchange

The accumulation of aluminium (Al) can cause Al bone deposits, osteomalacia and encephalopathy. As albumin solutions used as replacement fluid in plasma exchange (PE) are contaminated with Al, we studied Al overload in two symptomless patients with normal renal function, treated by long-term plasma exchange (PE). Total Al loading was calculated at 1750 mumol in patient 1 (178 PE sessions) and 2100 mumol in patient 2 (153 PE sessions). Bone biopsy showed Al deposits and low bone formation without osteomalacia in patient 1 and only osteoporosis in patient 2. Plasma Al levels were useless in detecting early Al overload, because the remained in the normal range, even after PE in both patients. Bone biopsy was the best means of recognizing Al intoxication, but cannot be recommended for frequent evaluations. However, the desferrioxamine mobilization test can be proposed as a repetitive non-invasive investigation method.