There are two medical conditions that are commonly referred to as lockjaw, and they have different causes. Trismus prevents the sufferer from opening his or her mouth normally, and its most common causes include inflammation of the muscles or tissues in the jaw area, a temporomandibular joint (TMJ) disorder or a complication of tonsillitis. Tetanus results in muscular spasms and prolonged muscle contractions throughout the body, including the jaw, and is caused by an infection of a bacterium called Clostridium tetani.
Trismus
Any restriction or inability of a person to open his or her mouth can be referred to as trismus. Severe cases are often referred to as lockjaw. There are many possible causes, including trauma and various infections and diseases that affect the mouth or jaw area. Disorders of the central nervous system also might cause a person to become unable to open his or her mouth normally. Dental surgeries, such as a molar extraction, can cause inflammation that also might result in lockjaw.
Tetanus
One of the symptoms of tetanus is a tightening of the jaw muscles. This can gradually cause the jaw to become difficult to manipulate, affecting speech and swallowing. Untreated, tetanus can cause death, although this has become fairly infrequent because of vaccinations and the practice of re-inoculating people who have gotten cuts from dirty metal objects.
Tetanus is caused by a bacteria called Clostridium tetani. This disease was once thought to be caused by cuts obtained around horses, which are frequent victims of tetanus. Clostridium tetani, however, lives abundantly in soil all over the world. It can survive for about 40 years.
Incidence of tetanus is most frequent in third-world countries where inoculations are not routine. In fact, newborns make up about half the cases in countries that are unable to adhere to modern standards of cleanliness or where many people cannot afford the cost of vaccination. The leading cause of exposure to tetanus in these countries is the lack of proper care of the umbilical cord stump, which then becomes infected with Clostridium tetani.
When untreated, tetanus has death rates of about 30 percent for adults and 60 percent for infants. It is so deadly because the causal bacterium is a neurotoxin. As the disease progress, all of the facial muscles can become stiffened, causing lockjaw.
The sufferer's back, stomach and lower body might also be affected, creating a stiff but still painful paralysis. A side effect of the illness is violent seizures or muscle spasms, called tetany. The disease is extremely painful, particularly for victims who are experiencing tetany.