INTRODUCTION

Tetanus is a nervous system disorder characterized by muscle spasms that is caused by the toxin-producing anaerobe, Clostridium tetani, which is found in the soil. The clinical features of tetanus and its relationship to traumatic injuries were well known among the ancient Greeks and Egyptians and to many clinicians before the introduction of vaccination with tetanus toxoid in the 1940s. The term "lockjaw" (now called trismus) lives in modern parlance as a reminder of one of the cardinal features of tetanus: intense painful spasms of the masseter muscles.

Tetanus can present in one of four clinical patterns:

• Generalized
• Local
• Cephalic
• Neonatal

Although tetanus is now rare in the developed world, the disease remains a threat to all unvaccinated people, particularly in developing countries. Since C. tetani spores cannot be eliminated from the environment, immunization and proper treatment of wounds and traumatic injuries are crucial for tetanus prevention. The epidemiology, pathogenesis, clinical features, diagnosis, and management of tetanus will be reviewed here. The principles of prevention of tetanus and management of tetanus-prone wounds are discussed separately. (See "Tetanus-diphtheria toxoid vaccination in adults" and "Diphtheria, tetanus, and pertussis immunization in infants and children 0 through 6 years of age" and "Diphtheria, tetanus, and pertussis immunization in children 7 through 18 years of age" and "Overview of puncture wounds" and "Soft tissue infections due to dog and cat bites".)

EPIDEMIOLOGY

Developed countries — Because of almost universal vaccination of children with tetanus toxoid in developed countries, the incidence of tetanus in these regions has dropped dramatically and steadily since 1940. During the period between 2001 and 2008, the US Centers for Disease Control and Prevention (CDC) reported that there were 233 cases of tetanus in the United States, with an annual incidence of 0.10 cases/million population overall, and 0.23 cases/million among individuals ≥65 years of age [1]. The case-fatality rate was 13.2 percent overall, but was 31.3 percent among individuals ≥65 years of age.