|Classification and external resources|
Trismus, or lockjaw, refers to reduced opening of the jaws caused by spasm of the muscles of mastication, or may generally refer to all causes of limited mouth opening. It is a common problem with a variety of causes, and may interfere with eating, speech, oral hygiene, and could alter facial appearance. There is an increased risk of aspiration. Temporary trismus is much more common than permanent trismus, and may be distressing and painful, and limit or prevent medical examination or treatments requiring access to the oral cavity.
- 1 Definition
- 2 Differential diagnosis
- 2.1 Intra-articular causes
- 2.2 Extra-articular causes
- 3 Common causes
- 4 Other causes
- 5 Diagnostic approach
- 6 Treatment
- 7 Epidemiology
- 8 History
- 9 References
Classically, the definition of trismus is an inability to open the mouth due to muscular spasm, but more generally it refers to limited mouth opening of any cause. Another definition of trismus is simply a limitation of movement. Historically and commonly, the term lock jaw was sometimes used as a synonym for both trismus and tetanus. Definitions from popular medical dictionaries vary, e.g.:
"a motor disturbance of the trigeminal nerve, especially spasm of the masticatory muscles, with difficulty in opening the mouth (lockjaw); a characteristic early symptom of tetanus."
"a firm closing of the jaw due to tonic spasm of the muscles of mastication from disease of the motor branch of the trigeminal nerve. It is usually associated with general tetanus. Also called lockjaw."
"a prolonged tonic spasm of the muscles of the jaw."
"spasms of the muscles of mastication resulting in the inability to open the oral cavity; often symptomatic of pericoronitis."
Normal mouth opening ranges from 35 to 45 mm. Males usually have slightly greater mouth opening than females. (40-60mm)=(avg-35mm). The Normal Lateral movement is (8-12mm). Some have distinguished mild trismus as 20–30 mm interincisal opening, moderate as 10–20 mm and severe as less than 10 mm.
Trismus is derived from the Greek word trismos meaning "a scream; a grinding, rasping or gnashing"
|Commonly listed causes of trismus|
- True bony ankylosis: can result from trauma to chin, infections and from prolonged immobilization following condylar fracture
- Treatment – several surgical procedures are used to treat bony ankylosis, e.g.: Gap arthroplasty using interpositional materials between the cut segments.
- Fibrous ankylosis: usually results due to trauma and infection
- Treatment – trismus appliances in conjunction with physical therapy.
- Odontogenic- Pulpal
- Non-odontogenic- Peritonsillar abscess
- Brain abscess
- Parotid abscess
- The hallmark of a masticatory space infection is trismus or infection in anterior compartment of lateral pharyngeal space results in trismus. If these infections are unchecked, can spread to various facial spaces of the head and neck and lead to serious complications such as cervical cellulitis or mediastinitis.
- Treatment: Elimination of etiologic agent along with antibiotic coverage
- Trismus or lock jaw due to masseter muscle spasm, can be a primary presenting symptom in tetanus, Caused by clostridium tetani, where tetanospasmin (toxin) is responsible for muscle spasms.
- Prevention: primary immunization (DPT)
- Dental trismus is characterized by a difficulty in opening the jaw. It is a temporary condition with a duration usually not longer than two weeks. Dental trismus results from some sort of insult to the muscles of mastication, such as opening the jaw for a period of time or having a needle pass through a muscle. Typical dental anesthesia to the lower jaw often involves the needle passing into or through a muscle. In these cases it is usually the medial pterygoid or the buccinator muscles.
- Oral surgery procedures, as in the extraction of lower molar teeth, may cause trismus as a result either of inflammation to the muscles of mastication or direct trauma to the TMJ.
- Barbing of needles at the time of injection followed by tissue damage on withdrawal of the barbed needle causes post-injection persistent paresthesia, trismus and paresis.
- Treatment: in acute phase:
- Heat therapy
- A soft diet
- Muscle relaxants (if necessary)
- Note: When acute phase is over the patient should be advised to initiate physiotherapy for opening and closing mouth.
- Treatment: in acute phase:
Fractures, particularly those of the mandible and fractures of zygomatic arch and zygomatic arch complex, accidental incorporation of foreign bodies due to external traumatic injury. Treatment: fracture reduction, removal of foreign bodies with antibiotic coverage
- Extra-capsular disorders – Myofascial Pain Dysfunction Syndrome
- Intra-capsular problems – Disc displacement, arthritis, fibrosis, etc.
- Acute closed locked conditions – displaced meniscus
Tumors and oral care
Rarely, trismus is a symptom of nasopharyngeal or infratemporal tumors/ fibrosis of temporalis tendon, when patient has limited mouth opening, always premalignant conditions like oral submucous fibrosis (OSMF) should also be considered in differential diagnosis.
Succinyl choline, phenothiazines and tricyclic antidepressants causes trismus as a secondary effect. Trismus can be seen as an extra-pyramidal side-effect of metaclopromide, phenothiazines and other medications.
Radiotherapy and chemotherapy
- Complications of radiotherapy:
- Osteoradionecrosis may result in pain, trismus, suppuration and occasionally a foul smelling wound.
- When muscles of mastication are within the field of radiation, it leads to fibrosis and result in decreased mouth opening.
- Complications of Chemotherapy:
- Oral mucosal cells have high growth rate and are susceptible to the toxic effects of chemotherapy, which lead to stomatitis.
Congenital and developmental causes
- Hypertrophy of coronoid process causes interference of coronoid against the anteromedial margin of the zygomatic arch.
- Treatment: Coronoidectomy
- Trismus-pseudo-camtodactyly syndrome is a rare combination of hand, foot and mouth abnormalities and trismus.
- Hysteric patients: Through the mechanisms of conversion, the emotional conflict are converted into a physical symptom. E.g.: trismus
- Scleroderma: A condition marked by edema and induration of the skin involving facial region can cause trismus
- Pericoronitis (inflammation of soft tissue around impacted third molar) is the most common cause of trismus.
- Inflammation of muscles of mastication. It is a frequent sequel to surgical removal of mandibular third molars (lower wisdom teeth). The condition is usually resolved on its own in 10–14 days, during which time eating and oral hygiene are compromised. The application of heat (e.g. heat bag extraorally, and warm salt water intraorally) may help, reducing the severity and duration of the condition.
- Peritonsillar abscess, a complication of tonsillitis which usually presents with sore throat, dysphagia, fever, and change in voice.
- Temporomandibular joint dysfunction (TMD).
- Trismus is often mistaken as a common temporary side effect of many stimulants of the sympathetic nervous system. Users of amphetamines as well as many other pharmacological agents commonly report bruxism as a side-effect; however, it is sometimes mis-referred to as trismus. Users' jaws do not lock, but rather the muscles become tight and the jaw clenched. It is still perfectly possible to open the mouth.
- Submucous fibrosis.
- Fracture of the zygomatic arch.
- Acute osteomyelitis
- Ankylosis of the TMJ (fibrous or bony)
- Condylar fracture or other trauma.
- Gaucher disease which is caused by deficiency of the enzyme glucocerebrosidase.
- Giant cell arteritis
- Local anesthesia (dental injections into the infratemporal fossa)
- Needle prick to the medial pterygoid muscle
- Oral submucous fibrosis.
- Radiation therapy to the head and neck.
- Tetanus, also called lockjaw for this reason
- Malignant hyperthermia
- Malaria severa
- Secondary to neuroleptic drug use
- Malignant otitis externa
- Peritonsillar abscess
- Retropharyngeal or parapharyngeal abscess
X-ray/ CT scan taken from the TMJ to see if there is any damage to the TMJ and surrounding structures.
Treatment requires treating the underlying condition with dental treatments, physical therapy, and passive range of motion devices. Additionally, control of symptoms with pain medications (NSAIDs), muscle relaxants, and warm compresses may be used.
Splints have been used.
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Historically, the term trismus was used to describe the early effects of tetany, also called "lock jaw".
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- Chris. "Dr.". Locked Jaw (Lockjaw and Slack Jaw) Meaning and Causes |. Healthhype.com. Retrieved 13 September 2012.
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