Troponin I versus Creatinine Kinase-MB as Predictor Markers of the Severity and Outcomes in Acute Theophylline Toxicity

Abstract Theophylline is a type of diethylxanthine that continues to be widely used in many developing countries for the treatment of acute and chronic bronchial asthma, chronic obstructive pulmonary disease (COPD) and apnea of prematurity. Methylxanthine cardiotoxicity is based on diverse, complex mechanisms. PDE inhibition and blocking adenosine receptors cannot explain all the cardiotoxic effects of methylxanthine. In addition, methylxanthines are cardiac stimulants and result in positive inotropy and chronotropy even with therapeutic dosing; myocardial ischemia and myocardial infarction (MI) are associated with acute theophylline poisoning. The current study aimed to investigate troponin I and creatine kinase-MB as predictors of the severity and outcomes in cases of acute theophylline intoxication. No previous studies have proposed early predictors of cardiovascular toxicities among methylxanthine users, early recognition of the severity of theophylline toxicity can be lifesaving and needs aggressive supportive care to improve clinical outcomes in patients. This study was a prospective cohort study conducted on 34 patients admitted to the Poison Control Center at Ain Shams University Hospitals (PCC-ASUH) for a 6-month duration from January 2022 to June 2022 with a history of acute exposure to theophylline toxicity. with history of acute exposure to theophylline toxicity. Patients were subjected to personal and toxicological history taking, vital signs collection, grading of acute theophylline toxicity and measurement of serum theophylline level. Both troponin I and creatine kinase-MB were measured at 6 and 12 hours post admission. Results revealed that, troponin I level at 6 hours post ingestion and 12 hours post ingestion in addition to creatine kinase-MB level at 12 hours post ingestion were significantly higher in cases with severe acute theophylline intoxication and patients who required intensive care unit admission and hemodialysis. It was concluded that, troponin I could predict the severity and the requirement of ICU admission and hemodialysis in patients with acute theophylline toxicity either with early or delayed presentation. On the other hand, CK-MB could be considered for patients with delayed presentation. Depending on time of admission, proper choosing of the biomarker to be investigated will allow for better evaluation of patients with saving extra cost.