Sequential evaluation of serum urate concentrations in AIDS patients with infections of the central nervous system

To evaluate the serum urate levels in AIDS patients with infections of the central nervous system (CNS), 46 patients who had at least two measurements of urate were included. A maximum of four measurements per patient were considered: prior to the CNS involvement (U-PRIOR), at the time of CNS involvement (U-CNS), after treatment for the CNS infection (U-AFTER), and the last measurement before death (U-LAST). Serum U-CNS levels were significantly lower than U-PRIOR values (p=0.038). U-AFTER levels were higher than U-CNS in the patients who improved (p=0.25), and lower in the patients who did not improve (p=0.026). There were no significant differences among the four diagnostic groups in U-CNS measurement (p=0.29) but they were found in U-AFTER determinations (p=0.018), probably as a result of the different response to treatment. Hypouricemia seemed to be associated with lower survival periods. We conclude that hypouricemia is common in AIDS patients with CNS infections, probably as a result of increased renal losses of urate, and that it may have prognostic significance. CNS infections are associated with significant decreases in serum urate levels in comparison with previous values. The urate concentrations seem to increase after successful treatment of the CNS infections, whereas they decrease further in patients who do not improve.