A 17-year-old, previously healthy girl presented to the emergency department (ED) with a 1-day history of restricted mouth opening and neck pain. The pain was aggravated during jaw opening and chewing. She had severe limitation in jaw opening, and her jaw was asymmetric favoring the right side. She had difficulty rotating her neck and eating due to the severity of pain.
There was no antecedent history of trauma or drug intake. Her immunization status was appropriate for age, and the last dose of tetanus and diphtheria vaccines was given 4 years ago. Two weeks before her ED visit, she was evaluated for swelling over her right jaw and a diagnosis of dental abscess was made. She was treated with analgesics and amoxicillin/clavulanic acid, but 1 week later, the swelling worsened. She had returned to the urgent care clinic, where computed tomography (CT) and ultrasonography (USG) showed sialadenitis, lymphadenopathy, and a bone defect on the second molar tooth level at ramus mandibula. No therapy changes were made.
On physical examination in our ED, she appeared alert and in moderate distress. She had a temperature of 36.1°C, heart rate of 88 beats/min, respiratory rate of 20 breaths/min, blood pressure of 122/78 mm Hg, and oxygen saturation of 98% in ambient air. She was unable to open her mouth more than 19 mm and refused to flex her neck due to pain. There was a 1.5 × 1 cm lymph node on the left side of her neck but no supraclavicular, axillary, femoral, or epitrochlear lymphadenopathy. Respiratory and cardiovascular examinations were unremarkable. Her abdomen was soft and there was no organomegaly. The remainder of her physical and neurologic examination was normal.
Laboratory findings showed a white blood cell count of 12.00 × 109/L with 66.2% neutrophils, 7.8% monocytes, 25.3% lymphocytes, 0.6% eosinophils, and 0.1 basophils; hemoglobin of 12.3 g/dL, and platelet count of 491 × 109/L; erythrocyte sedimentation rate was 60 mm/h (normal value 0–20 mm/h), and C-reactive protein (CRP) was 33.6 mg/L, (normal range: 0–5 mg/L). Electrolytes, blood urea nitrogen, and creatinine were normal, as were amylase, lipase, lactate dehydrogenase, and creatine kinase. Maxillofacial and neck CT and USG did not show any pathology.
She was empirically treated with intravenous ampicillin-sulbactam. Due to persistence of her trismus, an additional study was performed which revealed the diagnosis.
For Denouement see P. 1152.
(Pediatr Infect Dis J 2021;40:1152)
Continued from P. 1151.
The etiology of trismus is diverse, and any condition that restricts the movement of the jaw may cause trismus. These include infection, trauma, dental infection, temporomandibular joint disorder, tumors, drugs, radiotherapy, chemotherapy, congenital problems, and miscellaneous disorders.1–3 In our case, magnetic resonance imaging showed myositis of the medial and lateral pterygoid muscles (Fig. 1), which was likely an extension from the patient’s dental infection and the etiology of her trismus. Infectious pyomyositis of neck region muscles are characterized by fever, facial pain, swelling, and tenderness and is a potential life-threatening condition.4 It may occur in any muscle but usually involves the medial or lateral pterygoid muscles, which play an important role in the control of jaw movement necessary for mastication by acting together to lower the mandible and open the jaw.5,6 Therefore, if either muscle is affected for any reason, it will result in trismus. Medial pterygoid myositis is typically associated with traumatic injury or dental infection.4The very few reported cases of lateral pterygoid myositis occurred as a complication of dental infection.4,5 Odontogenic infections arising in the maxilla tend to spread first to the masticator space.5
Dentoalveolar infections are one of the most common diseases in the oral region. An acute dental abscess can occur secondary to dental caries, trauma, or root treatment.7 Most oropharyngeal infections are self-limited, but sometimes a dentoalveolar infection can spread through the fascia and deep neck spaces, resulting in airway obstruction, deep neck infection, mediastinitis, myositis, necrotizing fasciitis, and sepsis.7 The infratemporal fossa is one of the potential spaces for infection most commonly of dental origin, and contiguous with the pterygopalatine fossa, the parapharyngeal space, the orbit, and the cranial cavity. Trismus is the hallmark of infratemporal fossa infection, secondary to the irritation of the pterygoid muscles located in this space.8
Varshney et al reported a case of odontogenic infection spreading from the tooth to the infratemporal fossa progressing further to create a pterygoid muscle abscess.8 Differentiating between pterygoid muscle myositis and deep neck infection is crucial. Deep neck infections are important otolaryngologic emergencies due to serious complications causing mortality.9 Frequently, deep neck infections are complication of tonsillitis; however, in the recent literature, a relative increase of deep neck infections in the adult population has been reported to be associated with odontogenic causes.9
The diagnosis of pterygoid muscle myositis can be difficult. The pterygoid muscles are physically inaccessible to direct examination.1,5,10 Laboratory tests are generally nonspecific and of limited value. white blood cell count is elevated in 60% of cases, and CRP and erythrocyte sedimentation rate are also often elevated.11 The serum creatinine kinase can be high in severe cases.11 Imaging is essential for the diagnosis of myositis.11 CT may be useful to identify traumatic etiologies including hematomas, but MRI is more appropriate for the evaluation of soft tissue, cranial nerves, early abscesses, and coexisting regional inflammatory processes such as osteomyelitis.4,11,12 In our case, the patient experienced pain, which was aggravated by jaw opening and chewing, and exhibited severe limitations in mouth opening. USG and CT examination were not diagnostic, but MRI showed an abnormal enhancement of the left medial-lateral pterygoid muscle.
The treatment for myositis includes medical management using physiotherapy, soft diet, analgesic anti-inflammatory agents, muscle relaxant, and antibiotics.2,3,13 Patients with myositis can be treated with a single or a combination of antibiotics covering the aerobic and anaerobic oropharyngeal flora. Surgical drainage may be required in addition to antibiotics if an abscess is present.13 There is no consensus on the optimal duration of therapy in the literature with reported ranges from 2 to 6 weeks, depending on the clinical severity and the patient’s response.13 In our case, after the patient’s oral intake improved, we decided to switch from ampicillin-sulbactam therapy to oral cefuroxime axetil and metronidazole treatment. In addition to this treatment, we also administered thiocolchicoside, and naproxen. At the end of a 3-week treatment, her symptoms had completely resolved.
In conclusion, it is important for clinicians to be aware that lateral and medial pterygoid myositis is a rare complication of dental infection and can present with trismus.
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