The Centers for Disease Control and Prevention lists the symptoms of lockjaw as jaw spasms, headache, sudden and involuntary tightening of muscles and painful muscle stiffness throughout the body. Other symptoms include fever; perspiring; difficulty swallowing; elevated heart rate and blood pressure; and jerking or staring.
The CDC explains that lockjaw is an alternate name for tetanus; it gets the name because one of the first signs of the disease is a tightening or locking of the jaw muscles that prevents the mouth from opening. MedicineNet reports that lockjaw affects all the muscles in the body including those involved in breathing. Death can occur when this happens unless breathing support is provided. Even with such support, infections can occur within the airways that can be fatal. The CDC notes that 10 to 20 percent of lockjaw cases result in death.
The bacteria that cause lockjaw are found in soil and in the intestines of humans and animals, notes MedicineNet. The bacteria enter the body via breaks in the skin. It is common for them to enter through puncture wounds from nails and bites.
According to the New York State Department of Health, there is an effective vaccine that prevents lockjaw. A series of three tetanus vaccines are routinely administered to children, and booster vaccines should be administered every 10 years.