[Case of an 81-year-old woman with theophylline-associated seizures followed by partial seizures due to vitamin B6 deficiency].

We report an 81-year-old woman who suffered from theophylline-associated seizures followed by partial seizures due to vitamin B6 deficiency. She developed complex partial seizures. She had been treated with theophylline for two months because of chronic bronchitis. Brain diffusion-weighted magnetic resonance imaging (MRI) showed high intensity lesions in unilateral cerebral cortex and thalamus. Electroencephalogram presented periodic lateralized epileptiform discharges (PLEDs), and single photon emission computed tomography (SPECT) using 123I-IMP revealed increased blood flow in the same side of the cerebrum. We diagnosed as theophylline-associated seizures though blood theophylline concentration disclosed its therapeutic dose, and her symptom improved after theophylline was discontinued. She developed partial seizures again, after she suffered from diarrhea for two days. Laboratory examination showed that serum vitamin B6 was under the limitation of measurement, and intravenous supplementation of vitamin B6 stopped her seizures immediately. Theophylline may induce seizures independent of its blood concentration, and vitamin B6 deficiency may exist in the case of theophylline-associated seizures.