Tetanus is caused by the Clostridium tetani bacterium. Stiffness of the neck, jaw, and other muscles, often accompanied by a sneering, grinning expression They may also have problems communicating with others, and they may appear insensible to questions. Earlier … Sudden, involuntary muscle tightening (muscle spasms) — often in the stomach Spasms and stiffness in your jaw muscles (trismus) 2. Signs and symptoms of tetanus appear anytime from a few days to several weeks after tetanus bacteria enter your body through a wound. Two other frequent symptoms seen in people with tetanus are general anxiety and increased irritability. Difficulty swallowing 4. Signs and symptoms of tetanus are due to nervous system dysfunction and include progressive muscle spasms that cause stiffness and spasm of muscles throughout the body, including the breathing muscles. Fast facts on tetanus. Tetanus is often fatal. life-threatening infection caused by Clostridium tetani bacteria Because the body is overwhelmed by the bacterial infection, the affected individual may have difficulty staying still or following instructions. Tetanus affects the nerves that control your muscles, which can lead to difficulty swallowing. Stiffness of your neck muscles 3. You may also experience spasms and stiffness in various muscles, especially those in … Stiffness of your abdominal muscles 5. The early symptoms of tetanus include diarrhea, fever, and headache. Other associated symptoms can include headache, irritability, and restlessness. The average incubation period is seven to 10 days.Common signs and symptoms of tetanus include: 1.