Methicillin-resistant Staphylococcus aureus (MRSA)-associated juvenile osteomyelitis of mandible: a rare variant

Abstract

Mandibular osteomyelitis in paediatric population presents as painful swelling with progressive trismus. Often the aetiology for this form of progressive osteomyelitis is inconclusive. The infective aetiology in this condition is difficult to assign as bone tissue culture is found to be seldom positive. We present a case of an 11-year-old girl, with hearing and speech impairment, who presented with report of painful right-sided mandibular swelling with progressive trismus. Clinical, radiographic and histopathological findings were suggestive of sclerotic osteomyelitis. Bone tissue culture grew Methicillin-resistant Staphylococcus aureus, indicating a rare infective variant. Unlike the common belief, where osteomyelitic mandible needs a combination of medical and surgical management, our case was managed conservatively with only antibiotic therapy. Our patient responded well to the treatment with reduction in pain and gradual improvement in the mouth opening. Radiographically the mandibular involvement also showed complete regression.

Background

Osteomyelitis of the mandible is seen both in the adult population as well as in younger individuals. There exists varied terminology for this disease in adults, namely, Garre’s osteomyelitis, primary chronic osteomyelitis (PCO), diffuse sclerosing osteomyelitis (DSO).¹ Nonsuppurative osteomyelitis of mandible in paediatric cases always poses a diagnostic challenge for the treating clinicians. Heggie et al had suggested inflammatory, nonsuppurative osteomyelitis in paediatric population to be considered as a distinct clinical entity. The author stated that the biopsy is often inconclusive in most of osteomyelitis seen in the paediatric age group.² Osteomyelitis of the mandible as a result of infection secondary to Methicillin-resistant Staphylococcus aureus (MRSA) has rarely been reported in children. Radiographic as well as CT findings are usually consistent with sclerotic osteomyelitis with subperiosteal bone formation, mixed radiodense and radiolucent trabecular pattern.² Inflammatory markers (erythrocyte sedimentation rate (ESR) and C reactive protein (CRP)) are frequently but not always increased.³ Characteristic features of mandibular osteomyelitis like pain, swelling, tenderness and trismus with associated mandibular bony changes were also evident in the present case. However, the bacterial contamination was confirmed by deeper bone tissue culture. This case report highlights the current understanding of paediatric infective form of osteomyelitis. Our case uniquely had positive culture findings and responded well to antibiotic therapy. Unlike the common belief, where osteomyelitic mandible needs surgical management, this case was managed conservatively with antibiotic therapy. The patient responded well to antibiotic therapy with gradual reduction in pain, swelling and increase in mouth opening. Radiographically the bony mandibular involvement showed complete regression in subsequent follow-up visit, henceforth emphasising the importance of antibiotic therapy in these cases.

Case presentation

An 11-year-old girl, with hearing and speech impairment since childhood, came to the section of oral and maxillofacial surgery with a report of pain and swelling in the right side of mandible with progressive trismus since 5 months following extraction of an infected primary molar. Extraoral examination revealed a diffuse, mildly tender swelling, which was firm on palpation. The right submandibular lymph node was palpable, nontender and mobile (figure 1). The patient had a maximum mouth opening of 10 mm (figure 2). Intraoral examination revealed tenderness and swelling in right lower buccal vestibule in relation to erupting second molar (figure 3). The patient’s medical history revealed that she had been treated for primary complex tuberculosis when she was 1.5 years of age and had complete remission. The patient had undergone lymph node biopsy for the cervical lymphadenopathy, which ruled out relapse of tuberculosis. Patient had apparently taken multiple course of antibiotic therapy for similar episodes of pain and trismus in the past 5 months, however, the symptoms had progressed gradually.

Figure 1.

Facial swelling on the right side of the face at the time of presentation.

Figure 2.

Mouth opening (10 mm) at the time of presentation.

Figure 3.

Intraoral presentation.

Investigations

An orthopantomogram (OPG) revealed a mixed radiopaque and radiolucent lesion involving the right-side ramus-angle body region of the mandible involving the roots of lower second molar tooth (figure 4). CT scan was advised, which revealed partial destruction of the right ramus of mandible with periosteal bone formation and sclerosis involving the right half of the body of mandible (figures 5–7). Complete blood count was within normal limits. A raised ESR—75 mm and CRP—14.6 mg/L were suggestive of underlying infection. A differential diagnosis of Tuberculous osteomyelitis and nonsuppurative osteomyelitis was made. Extraction of the partly erupted right lower second molar was done and bone biopsy was performed after from the bone tissue at the depth of the extraction socket (figure 8). Histopathology revealed chronic osteomyelitis changes with no evidence of bacterial or fungal organisms or acid-fast bacilli. Tissue culture of the bone tissue showed scanty growth of MRSA, alpha-haemolytic streptococci and beta-haemolytic group A streptococci, of which the MRSA was susceptible to cotrimoxazole and rifampicin and the streptococci were susceptible to vancomycin and penicillin. The culture was negative for fungal growth and the Xpert TB PCR was negative for tuberculosis, as were the Acid-fast bacillus (AFB)smear and mycobacterial culture.

Figure 4.

Orthopantomogram showing mixed radiopaque and radiolucent lesion involving the right-side ramus-angle-body region of the mandible.

Figure 5.

Coronal CT showing sequestrum suggestive of right-side osteomyelitis of the ramus of mandible.

Figure 6.

CT three-dimensional reconstruction showing osteomyelitic changes of the right-side mandible.

Figure 7.

CT three-dimensional right-side bone involvement of the mandible showing asymmetry.

Figure 8.

Extracted tooth number 47 with bone tissue from the deeper part of socket number 47.

Final diagnosis

Based on the patient’s clinical presentation, radiographic characteristics and histopathology, a diagnosis of MRSA-associated nonsuppurative osteomyelitis of mandible was made.

Treatment

In consultation with the paediatric infectious disease specialist, the child was given intravenous vancomycin and amoxicillin with clavulanic acid for 14 days. The patient’s mouth opening gradually improved. The patient was then given oral antibiotic therapy for an additional 6 months with triple-drug regimen of oral cotrimoxazole, amoxicillin-clavulanate and rifampicin.

Outcome and follow-up

The patient was asymptomatic at 1-year-follow-up visit, with improved mouth opening to 45 mm (figures 9–11). Blood investigations showed marked improvement with ESR of 17 mm, CRP of <3.03 mg/L. OPG and CT scan also revealed normal bone formation with complete healing (figures 12–15).

Figure 9.

Normal follow-up profile picture after 1 year of antibiotic therapy.

Figure 10.

Follow-up intraoral picture.

Figure 11.

Mouth opening improved to 45 mm after 1 year follow-up.

Figure 12.

Postoperative orthopantomogram showing normal bone in right-side ramus-angle body region of the mandible.

Figure 13.

1 year follow-up coronal cut CT shows normal bone formation.

Figure 14.

CT three-dimensional reconstruction at 1 year follow-up.

Figure 15.

CT three-dimensional reconstruction showing normal bone symmetry.

Discussion

Various terminologies for nonsuppurative form of the mandibular osteomyelitis exist in the literature. Adult osteomyelitis is often termed as PCO, DSO or Garre’s osteomyelitis.³ PCO in paediatric patients has been a subject of dilemma with regards to disease characterisation and management. Most common terminology for paediatric form of chronic nonsuppurative mandibular osteomyelitis includes juvenile chronic osteomyelitis (JCO) of mandible, with some authors correlating this disease process as part of synovitis, acne, pustulosis, hyperostosis and osteitis syndrome.^{4 5} JCO is an uncommon but well-recognised disease entity characterised by multiple episodes of pain, swelling, tenderness and limited jaw motion and occurs predominantly in girls.² Patients with these clinical features of mandibular osteomyelitis are usually subjected to radiographic and CT evaluation. CT findings often show subperiosteal bone formation along with mixed radiolucent and radiodense trabecular patterns, which are suggestive of osteomyelitis. However, the main clinical dilemma associated with paediatric nonsuppurative osteomyelitis is identifying the aetiology for the disease process. Aetiopathogenesis often remains uncertain as standard tissue cultures are frequently negative for bacteria.⁶ Renapurkar et al and other authors have stated inaccurate cultures and contamination as the reason for flaw in establishing bacterial aetiology and have reasoned the disease as having infective aetiology based on various molecular studies for odontogenic infection.^{1 7} In our case, bone tissue biopsy was taken from deeper extraction socket and subsequent tissue culture was reported to be positive for MRSA. Histopathology was also confirmatory for chronic nonsuppurative osteomyelitis of mandible. Henceforth, a final diagnosis of MRSA-induced osteomyelitis of mandible was made and antibacterial therapy was initiated. MRSA infection causing paediatric osteomyelitis has seldom being reported in the literature. S. aureus bacteremia in a 23-week preterm infant complicating in a suppurative form of MRSA-associated mandibular osteomyelitis was reported by Silvia et al. The authors reported complete clinical and radiographical healing after antibiotic therapy similar to our patient.⁸ Tuzuner et al have reported a case of MRSA-associated suppurative osteomyelitis of mandible in 35-year-old male patient.⁹ MRSA-associated maxillary osteomyelitis in a 33-year-old woman has also been reported by Cohen et al. The authors stated that MRSA infection of maxilla was implicated by previous dental or oral surgical procedure.¹⁰ Our case stands out as a rare reported case of MRSA-associated osteomyelitis of paediatric mandible and supports the findings of Renapurkar et al, that infection is the prime reason for disease progression in juvenile osteomyelitis.¹

A range of treatment modalities has been reported in the management of JCO of mandible. Eyrich et al advocated treatment with biopsy, decortication and antibiotics.⁴ Obel et al reported the use of steroids with NSAIDS in the management of noninflammatory form of juvenile osteomyelitits of mandible.¹¹ Jacobsson and Hollender in their retrospective study of sclerosing osteomyelitits in mixed group of population have shown that the long-term antibiotic therapy was beneficial in most of these patients and decortication assists in relieving the symptoms.¹²

Our case was managed effectively with only antimicrobial therapy. This emphasises the role of culture biopsy and conservative approach with long-term antibiotic therapy as key in management of these patients. Role of CRP and ESR as prognostic indicators is also important to assess the outcome during the course of antibiotic treatment. CRP reduced from 14.6 mg/L to <3.03 mg/L and ESR values reduced from 75 mm to 17 mm at 1-year follow-up for our patient following the antibacterial therapy. Follow-up CT also showed complete recovery of the diseased mandible. Proper use of culture-specific antibiotic regimen in the management of JCO of mandible can, henceforth, give a good quality of life in these children by preventing morbid jaw sacrificing corticotomy or sequestrectomy surgeries.

Learning points.

• The protocol of obtaining adequately representative tissue biopsy and culture and subsequent long-term use of culture-specific antimicrobial agent is the key in managing juvenile osteomyelitis.

• Treatment outcome can be effectively assessed with prognostic indicators like erythrocyte sedimentation rate andC reactive protein.

• Methicillin-resistant Staphylococcus aureus (MRSA) is a possibility in infections of the maxilla or mandible and must be considered in management of infections not responding to conventional antibiotic therapy.

• This case report concludes that MRSA-associated infective form of juvenile osteomyelitis of mandible needs conservative management with antibiotics therapy.

Ethics statements

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