Lockjaw (trismus) is a painful condition that limits your ability to open your mouth all the way. It occurs when the muscles you use to chew spasm, meaning they can’t relax completely. The term “lockjaw” used to be used interchangeably with “tetanus,” a bacterial infection that causes lockjaw. “Lockjaw” is now recognized as one possible symptom of tetanus rather than the disease’s official name.
The most common symptom of lockjaw is being unable to completely open your mouth. Mouths usually open between 40-60 millimeters, which is about 1.5-2.3 inches. If you have lockjaw, you won’t be able to open your mouth any wider than 35 millimeters, or 1.35 inches.
The main signs of lockjaw include:
- Pain and tightness on one or both sides of the jaw
- Pain or difficulty when speaking or chewing
- Difficulty brushing or flossing teeth
- Symptoms that come on fast and peak within a couple of hours
- Partially open mouth while resting due to tense muscles
Other than having a locked jaw, additional symptoms you may experience include:
- Drooling or dry mouth
- Headaches
- Pain radiating to the neck or the rest of the jaw
- Swelling in the jaw
- Earaches
- Fever, sweating
- Muscle spasms (cramps) in other parts of the body or involuntary jerking motions
- Rises or drops in heart rate and blood pressure
Lockjaw is usually acute (short-term), though some people may develop chronic (long-term) cases.
Lockjaw happens when the masticatory muscles (muscles involved in chewing) spasm. This means they remain tense at rest and can’t relax, which affects the ability to move the jaw properly. These spasms can stem from many causes.
Conditions that can cause lockjaw include:
- An injury or damage to the ligaments, muscles, nerves, or bones in the jaw, such as from trauma due to accidents or sports.
- Tetanus, a bacterial infection that affects your muscles and nerves
- Temporomandibular disorders (TMD), conditions that affect the jaw joint and muscles controlling jaw movement
- Arthritis
- Oral (mouth) infections
- Medication or dental treatment side effects
- Head and neck cancers
- Certain cancer treatments, like radiotherapy (high-energy x-rays that destroy cancer cells)
Risk Factors
While anyone can develop lockjaw, certain individuals are at a greater risk. Health conditions and factors that raise risk include:
- Age 70 or over
- People assigned female at birth
- Diabetes
- Conditions that weaken the immune system, like cancer, autoimmune diseases, human immunodeficiency virus (HIV), and acquired immunodeficiency syndrome (AIDs)
- Injection (taken by vein) drug use
- Malocclusion (misaligned teeth)
- Arthritis
- History of oral surgery
- History of radiation therapy for head and neck cancer
When diagnosing lockjaw, healthcare providers work to find the underlying cause. They check your medical records to see if you have a history of cancer, cancer treatment, oral or dental injuries, oral surgery, or other risk factors.
They may also perform the following diagnostic tests:
- Physical exam: Most cases of lockjaw can be diagnosed by physically examining how the jaw and mouth move and learning about your symptoms.
- Blood test: Your provider may request a complete blood count (CBC) and other blood tests to check for signs of infection or inflammation. A CBC is a group of blood tests that measure the number and size of blood cells. However, blood tests can’t detect tetanus
- Computed tomography (CT) scan: These scans help providers diagnose and evaluate any jaw injury or fracture that’s causing symptoms.
- Magnetic resonance imaging (MRI): This test creates detailed images of the jaw joint, letting healthcare providers look for changes in the tissue (lesions).
Treatment options for lockjaw depend on the cause of symptoms and their severity. The goals of treatment are to relax the jaw muscles and manage discomfort. It also means addressing any underlying causes, such as tetanus, arthritis, or cancer.
Medications
A range of over-the-counter and prescription medications can ease lockjaw symptoms or treat the underlying cause:
- Non-steroidal anti-inflammatory drugs (NSAIDs) like Aspirin (acetylsalicylic acid) or Motrin (ibuprofen)
- Opioids, which are medicines used for pain relief, such as Percocet or Oxycontin (oxycodone)
- Muscle relaxers, such as Diastat (diazepam)
- Antibiotics for tetanus or bacterial infections
- Injectable muscle relaxers or Botox (botulinum toxin A)
Heat Therapy
Heat therapy is a home remedy that may ease the tension and pain from lockjaw. When applying heat to the affected area, it should increase blood flow, which in turn should lower discomfort, relax the jaw muscles, and make it easier to move the jaw. To try this method, apply a hot pad or moist hot towel to the jaw for 10-15 minutes at a time, every hour as needed.
Surgery
For severe cases of lockjaw where symptoms aren’t going away with other treatments, surgery may be necessary. Surgery may include:
- Lowering the height of the lower jaw bone (mandible)
- Coronoidectomy, which removes the end of the mandible
- Trismus release, in this case, involves removing scar tissue to ease tension on the jaw. Trismus release can also include non-surgical options.
- Free flap reconstruction, which moves tissue from another part of the body to the jaw after trismus release
Physical Therapy
Physical therapy helps with recovery after the worst lockjaw symptoms resolve. Working with a physical or speech therapist, you learn and practice exercises to help bring back mouth mobility (movement) and the ability to speak.
Dental Appliances
Your healthcare provider may have you wear specialized devices to help the mouth open wider. For lockjaw, these appliances may include jaw stretchers, stacked wooden tongue depressors, and temporomandibular joint (TMJ) and repositioning splints. Splints for lockjaw treatment are similar to night guards. However, they’re specifically made to help stretch the jaw muscles.
While there’s no way to completely prevent lockjaw, there are several things you can do to reduce your risk. You can lower your risk if you:
- Get a tetanus booster: Vaccines are highly successful in preventing tetanus. Since it starts to lose efficacy over time, you should get a booster every 10 years.
- Exercise: Physical therapy exercises and activities like chewing sugar-free gum can help build muscles, preventing TMJ-related lockjaw or relapses.
- Change medications: You may need to stop taking medications that cause lockjaw, such as antipsychotics like dopamine receptor 2 (D2) antagonists, and Reglan (metoclopramide), which treats nausea.
- Avoid certain foods: Steer clear of foods that are hard to chew, such as nuts, raw vegetables, hard candy, popcorn, and others.
Most cases of lockjaw clear up on their own within two weeks. If left untreated or if your lockjaw is due to a chronic condition, there can be complications. This includes:
- Aspiration: This is when saliva, food, or liquid enters the airways, which can lead to lung infection (pneumonia). Difficulty chewing and swallowing due to lockjaw increases the risk of aspiration.
- TMJ fibrosis: Prolonged and untreated lockjaw can cause TMJ muscles (muscles and tissues in the jaw joint) to develop scar tissue, or fibrosis.
- Laryngospasm: When caused by tetanus, the infection can spread to the vocal cords, causing these muscles to spasm, affecting the ability to speak.
- Pulmonary embolism: This is when a blood clot travels to the lungs.
- Respiratory failure: This is when the lungs stop working. Severe tetanus infections can spread to the lungs and blood, which can lead to respiratory failure.
Lockjaw occurs when you aren’t able to open your mouth fully, which can lead to tightness and pain when you chew or talk, and affect breathing. Many conditions can cause lockjaw, including tetanus, temporomandibular joint conditions, and dental procedure complications.
Older age, arthritis, diabetes, and using injection medications can raise your risk. Treatments for this condition depend on the underlying cause and include medications, physical therapy, and surgery. Avoiding hard-to-chew foods. Jaw exercises can help prevent it.
