Theophylline-induced seizures in a 6-month-old girl. Serum and cerebrospinal fluid levels.

The case is presented of a 6-month-old girl with theophylline-induced focal seizures associated with tachycardia, tremor and irritability. The serum level of theophylline was 20.0 micrograms/ml 30 min after the onset of seizures, and declined to half this level at 19 h. The ratio of the concentration in cerebrospinal fluid (CSF; 8.9 micrograms/ml) to serum (16.4 micrograms/ml) was 0.54 at 4.5 h after the onset. Despite the cessation of seizures, the EEG showed periodic high voltage delta waves over the right hemisphere and left-sided flatness. Since theophylline diffuses easily through the blood-brain barrier in infancy, serum levels should be maintained below 15 micrograms/ml unless severe bronchial asthma occurs.