Locked jaw caused by non-infectious inflammation of the lateral pterygoid muscle after dental treatment

Abstract

The author describes the case of a 53-year-old male whose jaw spontaneously locked the day after his dental visit. There was no history of temporomandibular problems. Dental procedure was completed in a routine manner. There was no infective or systemic pathology, or muscle spasm as a cause of trismus. Temporomandibular joint dysfunction was initially suspected, but dynamic ultrasonographic examination and MRI revealed a completely patent articular disc and normal temporomandibular joint. The patient did not have a mechanical restricted movement of the joint, but rather a severe, local pain upon depressing the mandible, which inhibited further opening. Intraoral palpation of the lateral pterygoid muscle (LPM) reproduced his symptoms, and thus suggested a myogenic etiology rather than arthropathy. Probably overstretching and subsequent inflammation of the LPM occurred due to prolonged mandibular depression. The patient was prescribed strengthening exercises for the LPM, which completely resolved his problem within 6 weeks. This case study suggests that overuse with subsequent inflammation of the LPM may cause locking of the jaw, mimicking radiculopathy.
Citation: Larsen K. Locked jaw caused by non-infectious inflammation of the lateral pterygoid muscle after dental treatment. Anaesth Pain & Intensive Care 2018;22(4):­­511-514
Received – 23 Nov 2018; Reviewed – 5 Dec 2018; Corrected & Accepted – 8 Dec 2018