Differential diagnosis
Traditionally causes of trismus are divided into intra-articular (factors within the temporomandibular joint [TMJ]) and extra-articular (factors outside the joint, see table). Joint problems
Ankylosis
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. Arthritis synovitis
Meniscus pathology
Extra-articular causes
Infection
Odontogenic- Pulpal
Periodontal
Pericoronal
Non-odontogenic- Peritonsillar abscess
Tetanus
Meningitis
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 treatment
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.
It is highly associated with NOTCH1 mutations.Other types include:

Large granular lymphocytic leukemia
Adult T-cell leukemia/lymphoma
T-cell prolymphocytic leukemiaIn practice, it can be hard to distinguish T-cell leukemia from T-cell lymphoma, and they are often grouped together. NK cell leukemia
Aggressive NK-cell leukemia (ANKL) is a lymphoid leukemia that is a deficiency NK cells. Not very much is known about this disease due to its rarity, but it is highly aggressive. Most patients will die within 2 years. Diagnosis
The requirements for diagnosing ANKL are as follows:
Immature-looking NK cells
Certain immunophenotypes
Germline configuration genes: TCR-β and IgH
Restricted cytotoxicityThe T-cell receptor (TCR) is an important factor when ANKL is being diagnosed along with T-cell leukemia. The TCR gene transcripts are normally positive for ANKL. Current Research is attempting to find the causation of ANKL. So far, the researchers have concluded that lineage of the T-cell receptor gene does not predict the behavior of the disease. Treatment
ANKL is treated similarly to most B-cell lymphomas. Anthracycline-containing chemotherapy regimens are commonly offered as the initial therapy. Some patients may receive a stem cell transplant. Most patients will die 2 years after diagnosis. Diagnosis
Flow cytometry is a diagnostic tool in order to count/visualize the amount of lymphatic cells in the body. T cells, B cells and NK cells are nearly impossible to distinguish under a microscope, therefore one must use a flow cytometer to distinguish them. Treatment
Targeted therapy
Several molecular tumor profiling protocols have been initiated in Europe (e.g., MOSCATO-01, iTHER, and ESMART) to identify actionable lesions for targeted treatment in specific subgroups of patients.