What is Trismus?
Trismus is a condition where the jaw’s movement becomes limited. This was initially identified in relation to a disease called tetanus but now it refers to any situation where there’s a restricted ability to open the mouth. Usually, this condition is temporary and gets better in less than 2 weeks. However, there can be cases where trismus becomes permanent, making daily tasks like talking, eating, and swallowing difficult. It can also make maintaining oral hygiene and undergoing dental procedures complicated.
What Causes Trismus?
Trismus is a medical condition that can cause your jaw to lock or make it difficult for you to open your mouth fully. This can happen due to a number of reasons. A sudden onset of trismus may be caused by injuries or damage to your face, lower jaw, or due to medical procedures such as tooth extraction or anesthesia administration. This type of trismus is usually temporary and resolves on its own. However, more severe injuries can result in long-term trismus.
The causes of constant trismus can include various disorders of the temporomandibular joint (TMJ), which connects your jawbone to the rest of your skull. These issues can also be due to cancer and its treatment, local infections, and connective tissue diseases like lupus.
If you have trismus after local anesthesia, it could be a complication of a nerve block procedure. If a muscle used for chewing, like the medial pterygoid muscle, is accidentally hit, it can result in trismus due to the pain. Trismus might also result from a blood clot or hematoma due to injury to the arteries or veins.
If you have had a tooth extraction, particularly your third molar, you might experience trismus as a complication due to the body’s inflammatory response. It’s usually a short-term problem.
Fractures in your lower jaw or injuries to your face can also lead to trismus because they can limit your mouth’s ability to open.
Infections related to your teeth can also cause trismus, particularly if these affect your chewing muscles. Serious dental infections may threaten life if they spread into your head, neck, and chest. Some non-teeth related infections that can cause trismus include tonsillitis, tetanus, meningitis, and brain abscesses.
If you start experiencing trismus without an obvious reason, it could be a sign of cancer, although this is rare. This could lead to delayed diagnosis of cancer, and that’s why physicians maintain checklists to identify unusual cases.
Finally, people who are being treated for head and neck cancer can experience trismus as a common side effect. Recent studies show that it can develop in around 38-42% of these patients.
Many health conditions can result in trismus. They can be broadly classified into traumatic, inflammatory, infectious, congenital malformations (birth defects), neoplasms (tumors), problems related to teeth, iatrogenic (resulting from medical treatment), neurogenic (relating to the nerves), and psychogenic (involving mental or emotional factors).
Remember, if you’re experiencing symptoms of trismus, make sure to seek medical help right away. It’s especially important to do so if you’re experiencing severe pain, have had a recent injury, or the symptoms do not resolve on their own after a short period of time. It’s important to get the right diagnosis and treatment, and remember – whether it’s a minor injury or a more serious underlying condition, medical professionals are there to help.
Risk Factors and Frequency for Trismus
Trismus, also known as lockjaw, occurs in a broad range of instances. This is partly because there aren’t clear guidelines to determine when it happens. The appearance of trismus often depends on the root cause. It is frequently seen in specific groups of people, like those born with a condition causing a small jaw, or those receiving radiation therapy for cancers in the head or neck. On a rare occasion, trismus can also become a side effect of common illnesses like a sore throat.
Signs and Symptoms of Trismus
Trismus, or the inability to open the mouth completely, often comes with discomfort and, sometimes, pain. The normal mouth opening size ranges from 40 to 60 cm, or about 2 to 3 finger breadths. But this can vary depending on the person and their gender, with males typically having a wider mouth opening. A maximum mouth opening of less than 35 mm is generally considered trismus.
When someone has trismus, they might complain more about the source of the problem rather than the trismus itself. For example, if a dental issue causes trismus, they might mention tooth or gum pain and swelling. If trauma caused it, they might bring up facial pain. Systemic causes need to be identified through a full clinical examination. Symptoms like fever, weight loss, muscle spasms and abnormal sensations might indicate an infectious, cancerous, neurogenic, or metabolic cause. Tobacco use or a history of cancer can point towards a cancer-related cause.
Trismus can also create hurdles during a physical exam, especially when trying to examine the mouth and throat. The doctor needs to focus on the teeth, gums, facial bones, joints, throat structures, and neck. They might need to assess the patient’s speech because certain infections that can cause trismus may also change the voice. In some cases, a “hot potato voice” might suggest tonsillitis or an infection near the tonsils. If needed, a focussed neurological examination can be performed to look for neurogenic causes.
Testing for Trismus
To diagnose trismus, which is a condition that restricts the mouth’s ability to open fully, doctors primarily rely on examining the patient’s condition. Medical imaging techniques might also be used to understand better the root cause of the problem and to check if the temporomandibular joint (the joint that connects your jaw to your skull) is affected.
Computed tomography, often known as a CT scan, can be useful in spotting issues that resulted from a trauma, such as blood clots (hematomas) or breaks in the facial bones or jaw. Magnetic resonance imaging, or MRI, can help identify if there is growth or irregularities in the structures of the throat or mouth.
Treatment Options for Trismus
Trismus, also known as lockjaw, is an uncomfortable condition that limits the opening of the mouth. Its treatment aims to address the root cause and primarily manages the symptoms. In the initial stage, the treatment usually involves heat therapy, pain relievers like non-steroidal anti-inflammatories (NSAIDs), muscle relaxants, and a soft diet.
Heat therapy involves applying warm moist towels to the affected area, while NSAIDs and muscle relaxants help in reducing pain and relaxing the muscles respectively. A typical muscle relaxant that might be used is a type of medicine called a benzodiazepine. Another helpful measure is to maintain a soft diet–that is, consuming foods that are soft and easy to chew–until the trismus gets better.
Stretching exercises could be beneficial after the initial phase of trismus or in cases where trismus persists for over a week due to trauma or surgery. These exercises involve attempting to open the mouth against resistance and are usually conducted multiple times a day. Another part of physical therapy may include moving the mouth side-to-side or opening and closing it, ideally every few hours. Chewing sugar-free gum can also aid in stimulating lateral movements and maintaining a healthy muscle function.
In some chronic cases, where trismus results from fibrosis (scar tissues) or ongoing cancer treatment like radiotherapy, intensive physiotherapy maybe helpful. Some treatments could include special exercises using commercially available jaw motion rehabilitation devices or a therapy called microcurrent therapy, especially for patients whose trismus has not improved with standard treatments. Some patients may consider medications such as xanthine derivatives like pentoxifylline.
If trismus continues for 2 to 3 days or becomes severe, a consultation with an oral and maxillofacial surgeon is recommended. In recurring and severe cases of trismus, a surgical procedure may be needed that might consist of lowering the height of the jawbone to enlarge the mouth opening, performing a coronoidectomy (removing part of the jawbone), or releasing tissue and reconstructing it.
What else can Trismus be?
Trismus is a condition characterized by the inability to fully open the mouth, regardless of the cause. Some experts believe that “true trismus” is controlled by a nerve in the face (the trigeminal nerve), and conditions like TMJ ankylosis or fibrosis, which are internal causes of restricted mouth opening, should be classified separately. However, other experts suggest that these internal causes should be seen as subcategories of trismus.
What to expect with Trismus
Trismus, or lockjaw, usually gets better on its own and typically goes away within 2 weeks. However, in certain circumstances, such as patients who develop tissue hardening from radiotherapy, it may take longer for trismus to resolve and it may be resistant to traditional treatment methods.
Possible Complications When Diagnosed with Trismus
Trismus, or limited mouth opening, can make talking, eating, and swallowing difficult. It may also lead to aspiration, a condition where food or liquid goes into your windpipe instead of your stomach, because it hampers the normal swallowing process. Severe trismus could make common medical procedures, like oral intubation, impossible, and might require alternative methods like intubation through the nose or a tracheotomy – an incision in the windpipe. If trismus lasts a long time, it can result in fibrosis (scar tissue) of the TMJ (temporomandibular joint, which connects your jawbone to your skull), which would need targeted treatment.
Common Effects of Trismus:
- Difficulty in speaking
- Trouble with eating
- Problems with swallowing
- Potential aspiration
- Difficulty in performing oral intubation
- Possibility of fibrotic changes in the jaw joint
Preventing Trismus
Patients should be advised to rest their jaws and stay clear of habits such as nail-biting and teeth clenching. They can potentially strain the jaw muscles and impede their recovery. In some circumstances, it may be beneficial for the patient to work with a physical therapist who can assist with exercises aimed at strengthening the jaw muscles.
