Neurophysiologic evaluation of long-term desferrioxamine therapy in beta-thalassemia patients.

Forty patients with beta-thalassemia major (BTM), between 11 and 19 years of age and maintained on long-term desferrioxamine (DFO) treatment, were examined by evoked potential and nerve conduction velocity studies to investigate a possible involvement of the auditory, visual, somatosensory, or peripheral nervous pathways. Pathologic findings in brainstem auditory-, visual-, and somatosensory-evoked potentials, and nerve conduction velocity studies were demonstrated in 25%, 15%, 7.5%, and 25% of the patients, respectively, whereas 15% demonstrated involvement of multiple neural pathways. Subclinical involvement of the auditory pathway was statistically associated with higher mean daily DFO dose and longer duration of DFO therapy, whereas abnormalities regarding the somatosensory pathways were related to older age, longer mean duration of DFO therapy, and lower serum copper levels. Involvement of the peripheral nervous system was related to lower serum copper levels. Multiple involvement of neural pathways was related to longer mean duration of DFO therapy. We conclude that risk factors related to long-term DFO treatment are only partly responsible for the subclinical involvement of neural pathways demonstrated in beta-thalassemia major patients.