Histopathology of the heart in tetanus

Despite modern intensive care, the mortality rate for systemic tetanus intoxication remains high. The prevention of deaths attributable to respiratory muscle spasm has made apparent a clinical syndrome of cardiovascular instability characterized by labile blood pressure and heart rate and associated elevated plasma catecholamine levels. A 60-year-old man treated at our hospital demonstrated this clinical problem and was shown by echocardiography to have a left ventricular ejection fraction of only 8%. Electrocardiographic abnormalities and elevated creatine phosphokinase were further evidence of myocardial damage. At autopsy, the 430-g heart showed mild concentric left ventricular hypertrophy and minimal coronary atherosclerosis. Microscopically there were interstitial edema, collections of Anitschkow cells, and a diffuse lymphohistiocytic infiltrate with rare plasma cells and granulocytes. Review of all cases of tetanus recorded at the Dade County Medical Examiner's Office since 1955 was undertaken. Of 52 cases, 23 had hematoxylin-eosin-stained glass slides of heart sections; for 10 of these, paraffin blocks were also available. Histopathologic features of cardiac injury included interstitial edema, increased cellularity of the interstitium (lymphocytes, histiocytes, Anitschkow cells, and rare plasma cells and granulocytes), intracellular edema, sarcoplasmic hypereosinophilia, and paradiscal contraction bands. Immunoperoxidase stains revealed that the majority of the lymphocytes in these hearts were T cells. Hypotheses as to the etiology and pathogenesis of these cardiac changes are reviewed.