The Clinical Im p lication of Theophylline Intoxication in the Emergency Department

Abstract

We reviewed the clinical manifestations of 53 episodes of theophylline intoxication in 50 patients over a one year study period, in order to identify the specific features as they presented to the Emergency Department (ED). There was a trend to an increase in the serum theophylline concentration with increased severity of clinical features, but the difference between the mild and the moderate cases was not statistically significant. The most common symptoms and signs were gastrointestinal complaints, sinus tachycardia, and atrial arrhythmias. Mixed atrial and ventricular arrhythmias, which are rarely mentioned as a specific feature of theophylline intoxication, were found in 16% of our patients and accounted for 29% of the cardiovascular manifestations. Four patients developed rhabdomyolysis, which presumably was secondary to a seizure or profound hypokalaemia. Cases of theophylline intoxication presenting to the ED had higher serum concentrations of theophylline and tended to have more severe toxicity than those patients in the non-ED group. Delayed diagnosis may contribute to the severity of the outcome, since severe cases in the ED were usually suspected to have developed intoxication at some point later in the stay in the ED than at the time of presentation, or after admission to the hospital, thus permitting the occurrence of an additional iatrogenic component to the intoxication. They also complained of symptoms not associated with the theophylline toxicity, which may have diverted the physician's attention from recognizing this concurrent problem. The other possible contributory reason for the severe and fatal outcomes was the use of a large dose of theophylline in the ED in the presence of coexisting factors that ordinarily indicate a low dose of theophylline.