Diagnostic Challenge and Clinical Management of Juvenile Mandibular Chronic Osteomyelitis

Abstract

Juvenile mandibular chronic osteomyelitis (JMCO) is a rare, idiopathic disease of chronic bone inflammation without suppuration, sinus tract formation, or sequestration. As the name suggests, this condition predominately affects children. The few cases of JMCO reported in the literature describe different treatments, and thus a standard therapy protocol has not yet been established. The aim of this paper is to report a clinical case in a 9-year-old girl that was misdiagnosed and unsuccessfully treated for 1 year. After experiencing persistent symptoms, a correct diagnosis was subsequently rendered based on the physical and radiographic examination as well as successful treatment with non-steroidal anti-inflammatory drugs (NSAIDs). The patient received drug therapy followed by periods of remission over a 4 year follow-up period. Diagnosis and treatment of JMCO is a challenge given the rarity and nonspecific signs and symptoms of this condition. Treatment with NSAIDs and regular follow-up is a conservative option for these patients.

Introduction

Osteomyelitis of the jaws is an inflammatory process that usually results from odontogenic infection [1–3]. On occasion, the etiology is unknown, such as in instances of juvenile mandibular chronic osteomyelitis (JMCO) [1–7]. JMCO, also referred to as primary chronic osteomyelitis, is a rare, non-suppurative form of chronic bone inflammation that presents without sinus tract formation or bone sequestration [1–3, 5, 7].

JMCO has an insidious onset with no acute phase [3, 5, 8]. Instead, intermittent signs and symptoms of variable intensity last a few days to several weeks in duration [8]. Signs and symptoms include painful swelling of the mandibular region, reduced mouth opening, and regional lymphadenopathy [2–5, 7, 9–11].

The diagnosis is supported by imaging that may include conventional radiography, computed tomography, magnetic resonance imaging, and/or bone scintigraphy [4–6, 8–13]. The histopathologic findings are non-specific but may demonstrate chronic inflammatory cell infiltration, bone marrow fibrosis, and sclerotic bone formation [2, 3, 6, 8–11].

While antibiotic therapy is ineffective for treatment of JMCO, non-steroidal anti-inflammatory drugs (NSAIDs) have been used with success [5, 8, 14]. Considering the rarity of this condition and the challenges of diagnosis and clinical management, we report a conservatively managed case with a 4-year follow-up.

Case Report

A 9-year-old girl was referred to Oral Medicine Service at the University Hospital of the Federal University of Santa Catarina, Brazil. During the past year, she experienced painful episodes of right parotid swelling accompanied by limited mouth opening (Fig. 1a). These episodes were interspersed with periods of remission. Review of her medical history revealed a past misdiagnosis of mumps based on these symptoms. After 2 months without improvement of the presumed mumps infection, she was hospitalized with a suspicion of a cytomegalovirus (CMV) infection. Blood tests were negative for CMV, and the painful parotid swelling recurred 1 month after hospital discharge. She was then unsuccessfully treated with antibiotics for parotitis before presenting to our clinic.

Fig. 1.

a Swelling on the right side of the face, causing facial asymmetry and severe pain. b Postero-anterior radiograph showing the periosteal reaction with maintenance of the original cortices. c Fan beam computed tomography showing buccolingual thickening and increased bone density, cortical remodeling and periosteal bone formation, suspicious areas of a disrupted cortical plate, and no evidence of mandibular canal cortication. d Panoramic radiograph showing diffuse radiopacity in the right mandibular ramus and an enlarged mandibular canal with irregular contour

Imaging assessment was performed during this first investigation period (Fig. 1b–d). Contrast-enhanced computed tomography (CT) showed no alterations in the parotid gland. A panoramic radiograph revealed diffuse radiopacities in the right mandibular ramus with enlargement and irregular contour of the mandibular canal. A postero-anterior skull radiograph showed buccolingual right mandibular ramus enlargement. Bone evaluation of the CT images confirmed buccolingual thickening associated with medullary bone sclerosis with a ground glass pattern, small lytic areas, cortical remodeling, and periosteal bone formation. There was no thickening of the ipsilateral masseter muscle.

A firm, painful swelling in the right side of the face was detected by extraoral palpation. No cervical lymph node enlargement was noted. Intraoral examination revealed reduced mouth opening and slight enlargement of the right mandibular ramus. The surface mucosa of the ramus was intact and normal in coloration. No carious lesions of the dentition were observed. The diagnosis of JMCO was established based on the patient’s previous history, imaging studies, and clinical presentation.

The patient was treated with 50 mg/day of indomethacin. The clinical status improved, and the NSAIDs were discontinued after 1 month (Fig. 2a). The patient remained asymptomatic for 2 weeks before the pain and swelling returned. The therapeutic regimen was resumed but without improvement. The dose was adjusted to 100 mg/day and eventually further increased to 150 mg/day. Intermittent drug therapy maintained a stable clinical status. Periodic hematological tests were performed with normal results. Follow-up panoramic radiographs showed normal bone structure with minimal enlargement and only a slight irregular contour of the mandibular canal compared with the contralateral side (Fig. 2b). The patient has been symptom-free and without medication for the last 3 years. She continues to be followed (Fig. 2c, d).

Fig. 2.

a Extraoral examination after 1 month of NSAID therapeutic scheme. b Panoramic radiograph taken as control showing partial resolution of disease. c Extraoral aspect after 5 years of clinical follows-up. d Panoramic radiograph showing normal bone architecture and mandibular canal contour in the right mandibular ramus

Discussion

The etiology of JMCO is unknown and patients generally have no infection, suppuration, sinus tract, or bony sequestra [1–5, 7–12]. In the present case, the patient had excellent oral hygiene. Patients with JMCO are frequently misdiagnosed with juvenile recurrent parotitis due to the similar clinical characteristics [5, 8, 13]. Diagnosis and treatment of JMCO remains a challenge due to its rarity, nonspecific signs and symptoms, and the lack of evidence-based therapeutic protocols.

The chief complaint of our patient was facial asymmetry and recurrent swelling, with or without pain, discomfort, reduced mouth opening, and regional lymphadenopathy. Other authors report similar presentations [3–5, 7–12]. JMCO usually affects one side of the jaw with normal skin and mucosa overlying the affected bone [2, 4–6, 8, 10–12]. When the process involves multiple bones, the condition is referred to as chronic recurrent multiple osteomyelitis (CRMO) which shows the same clinical, radiographic, and histopathologic findings as JMCO. In cases of CRMO, bone scans show hyperactive foci of skeletal bone which can aid in the diagnosis [15, 16].

Imaging examinations are usually decisive for the diagnosis of JMCO [5, 13]. The characteristic findings include enlargement and change in contour of the mandible, a periosteal reaction, partial destruction of the cortical–cancellous border, lytic areas, enlargement of the mandibular nerve canal, and a sclerotic, “ground glass appearance,” or mixed radiopaque–radiolucent bone pattern [3, 4, 6–12, 17]. Adjacent soft tissue thickening is also frequently noted. The “ground glass” bone pattern frequently leads to the inclusion of fibrous dysplasia (FD) in the differential diagnosis. FD, however, is painless, and thus the presence of pain must be reported to the radiologist [5, 6]. Additionally, classical FD presents with ill-defined margins surrounding normal adjacent bone, differing from the JMCO which shows alternating areas of radiolucency and radiopacity [5].

Obel et al. suggested that a JMCO diagnosis should follow the criteria adapted from Manson et al. which comprises: (1) radiographic diagnosis of a mandibular bone lesion; (2) at least 6 months disease duration; (3) imaging tests showing osteomyelitis; (4) ineffective antibiotic therapy; and (5) no identifiable cause [8, 18]. Our patient’s presentation met each of these criteria.

JMCO does not have specific histopathologic characteristics since the disease is chronic and involves diverse processes. Various authors describe the histologic features differently, but many include the presence of an inflammatory cell infiltrate in the affected bone [2, 6, 8, 10, 11]. Some findings are similar to FD, but this entity has metaplastic bone trabeculae whereas JMCO demonstrates peripheral osteoblasts, bone marrow fibrosis and new bone formation [5, 6, 9, 11, 12]. Most patients have a negative bacterial or fungi culture [3, 5, 6, 10, 11, 13]. The diagnosis for our patient was established based on findings from the history, clinical presentation, and imaging. The successful NSAID therapeutic regimen was also confirmatory.

A range of modalities have been used in the treatment of JMCO. Surgical treatments such as decortication are reported; however, conservative treatment is an attractive alternative approach, especially in young patients [2, 3, 5, 8–11]. The most effective reported treatment is NSAID therapy which was also successful for our patient [8, 14]. Some authors consider antibiotic therapy ineffective, and no measurable clinical effects were reported by our patient [6, 8, 14]. Additional treatments such as interferons α or γ, hyperbaric oxygen therapy, glucocorticoids, tumor necrosis factor neutralizing agents, and bisphosphonates have been reported as successful options in CRMO and in some relapsing cases [7, 16, 19–22]. Long term outcomes and larger cohort studies are needed for the evaluation of therapeutic strategies [14].

No specific NSAID protocols for the treatment of JMCO have been reported. In a case series by Obel et al. three patients were effectively treated with ibuprofen 200 mg 3 times/day, with one patient combining oral steroids with this regimen [8]. Heggie et al. used indomethacin 75 mg/day to treat eight patients, seven of whom showed symptom improvement and one required surgical treatment [5]. As shown in the present case report, the dose of the medication should be adjusted depending on the ongoing outcomes. Successful resolution is achieved when the pain and swelling subside and bone structures appear normal in imaging studies [14].

Conclusions

JMCO is a complex disease that should be regarded as separate from infectious osteomyelitis [5]. Because it is a rare condition with no identifiable cause, there is no established treatment protocol. We believe the first-line treatment should be NSAIDs, and surgical procedures should be avoided. Our patient received conservative treatment with NSAIDs which resulted in a favorable therapeutic response. The treatment of JMCO must be individually tailored, to include follow-up visits to evaluate patient progress, the need for treatment adjustment, and for signs of relapse. Further investigations are required due to the small number of reported cases of this rare childhood disorder.

Funding

This funding was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (BR)