INTRODUCTION: Autonomic disturbances in tetanus are traditionally associated with adrenergic variations and/or cardiac dysfunction, based on case report data. The objective of this study was to measure catecholamines, (TNF)-alpha and troponin T relative to and left ventricular ejection fraction (LVEF) in patients with severe tetanus. METHODS: This prospective study was carried out at two general Intensive Care Units and included 21 patients consecutively admitted with severe tetanus. Catecholamines (dopamine, norepinephrine, epinephrine and total catecholamines), tumor necrosis factor (TNF)-alpha and LVEF were assessed during the first week of autonomic instability and following tetanus recovery. Troponin T was measured during autonomic instability only. RESULTS: Mean age of patients was 46 +/- 17 years, median Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 8 (range 1-23). All patients had both blood pressure and heart rate instability. Two patients were recuperated from cardiac arrest. Intensive Care Unit mortality was 14% (3 cases). No increase in total catecholamines or in TNF-alpha levels was observed during autonomic instability or in the recovery period. Six patients had troponin T > 0.01 ng/ml and six had > 0.1 ng/ml. Mean LVEF was similar during autonomic instability and after tetanus recovery, 67 +/- 7% and 65 +/- 7%, respectively. Troponin T levels correlated with pressoric instability during autonomic instability. CONCLUSION: Our study demonstrated that in patients with severe tetanus no significant increased levels of catecholamines or TNF-alpha or evidence of cardiac systolic dysfunction was observed either during autonomic instability or in the recovery period. Elevated values of troponin T detected during autonomic instability were not associated with left ventricular dysfunction. Our data do not support the hypothesis that autonomic disturbances in tetanus are associated with adrenergic variations or cardiac dysfunction.