Definition of Tetanus:

Tetanus is a potentially deadly nervous system disease due to the bacteria Clostridium tetani (C. tetani).

Causes, incidence, and risk factors:

Spores of the bacteria C. tetani live in the soil and are found around the world. In the spore form, C. tetani may remain inactive in the soil, but it can remain infectious for more than 40 years.

Tetanus causes approximately five deaths per year in the United States. Internationally, it may reach up to 1 million cases a year. Tetanus infections in newborns make up about half of tetanus-related deaths in developing countries.

Infection begins when the spores enter the body through an injury or wound. The spores release active bacteria that spread and make a poison called tetanospasmin. Tetanospasmin blocks nerve signals from the spinal cord to the muscles, causing severe muscle spasm. Spasmodic contractions can be so powerful that they tear the muscles or cause compression fractures of the vertebrae.

Tetanus often begins with mild spasms in the jaw muscles (trismus), neck muscles, and facial muscles. Stiffness rapidly develops in the chest, back, abdominal muscles, and sometimes the laryngeal muscles (which then interferes with breathing). Muscular seizures (tetany) cause sudden, powerful, and painful contraction of muscle groups. These episodes can cause fractures and muscle tears.

The time between infection and the first sign of symptoms is 5 days to 15 weeks, with 7 days as the average. Most cases of tetanus in the United States occur in those who have not been properly vaccinated against the disease.