Jaw necrosis (osteomyelitis)
Osteomyelitis is a common sequel of chronic periapical infection and may also be caused by pathologies that obstruct blood supply, causing ischemia. This leads to bone death and necrosis. It can be acute or chronic in nature; primarily the difference between acute and chronic forms is the arbitrary time limit of a month after onset of disease. The acute form is more common and is the focus of this urgent care scenario.
- Patients with poor oral hygiene (severe periapical or periodontal infection) or penetrating contaminated injuries (open fractures and gunshot wounds)
- Patients with systemic diseases, such as Paget disease or osteopetrosis (rare)
- Patients with bone pathology (fibrous dysplasia and others)
- Hematogenous seeding from a distant site or in cases of sepsis (rare)
- Deep-seated throbbing pain, which may radiate to the jaw or forehead
- Swelling (initially soft because of edema, but later swelling becomes firm with involvement of the periosteum)
- Nonhealing necrotic bone, which may or may not be covered by inflamed oral mucosa
- Difficulty chewing and opening mouth (because of edema)
- Sequestrum formation
- Extraoral draining sinuses
- More common in the mandible than the maxilla (because the maxilla has higher vascularity).
- Tenderness of involved teeth
- Adjacent gingiva is erythematous, swollen and tender
- Numbness or paresthesia of lower lip if the mandible is involved
- Pain severity may range from mild to severe, depending on the stage of osteomyelitis (in acute stages, pain is severe)
- Obtain a detailed history:
- In the presence of pain, inquire about the onset, location, intensity and nature of the pain.
- Ask about fever or altered sensation in the lips (rule out paresthesia).
- Ask about the patient's medications, mainly bisphosphonates. When/why was the therapy started, and for how long is it prescribed?
- Ask about history of radiation therapy.
- Ask about any concurrent illnesses or conditions; focus on immunocompromising diseases, such as leukemia, diabetes mellitus and neutropenia.
- Ask about dysphagia or dyspnea, which may signify imminent airway compromise.
- Ask about allergies to medications.
- Perform a complete extraoral and intraoral examination (examine all oral mucosal surfaces):
- Extraoral exam:
- Complete a head and neck lymph node examination.
- Look for any extraoral draining sinuses or scars.
- Look for any fluctuance that may be amenable to incision and drainage.
- Investigate the extent of the swelling and see if the airway may be compromised. Intraoral exam:
- Check any bony swelling, and perform a bidigital palpation for the expansion of cortical plates. If cortical plates are expanded and thinned, there is eggshell crepitus.
- Palpate to examine continuity of the lower border of the mandible. In case of a pathological fracture, there will be a step deformity.
- Check for lip numbness and sensation in the soft tissues, which suggests nerve involvement.
- Check for any draining sinuses or scars; in case of draining sinuses, send the pus for microbial culture and sensitivity.
- Depending on the case, advise one or a combination of the following imaging modalities:
- Conventional radiography: periapical, panoramic or, occasionally, occlusal radiographs to visualize the expansion of cortical plates.
- Computed tomography (CT): use of contrast depends on the case. CT is superior to magnetic resonance imaging (MRI) for the detection of sequestra.
- MRI: occasionally use fat suppression images to see marrow patterns in suspected cases of ostemomyelitis because of its high resolution and ability to detect marrow patterns. MRI is highly sensitive for detecting osteomyelitis as early as 3–5 days after the onset of infection.
- Bone scan: use for early diagnosis of lesions with minimal bone loss. It can help detect osteomyelitis 10–14 days before changes are visible on plain radiographs. Bone scintigraphy is highly sensitive, but has low specificity, and it's difficult to differentiate between different pathologies. It is used as an adjunct, and specialist referral and consultation is required for prescribing such investigations.
- Blood investigations (complete blood count with differential in cases of active bacterial infection; look for neutrophilia) may be advised.
- Radiographic considerations:
- Initial stages may not present any radiographic changes because 30–40% demineralization is required for a lesion to be apparent on a radiograph.
- Initially, there is loss of the trabecular pattern of bone and areas of radiolucency. With more bone destruction, an ill-defined radiolucency can be visualized.
- Areas of dead bone become dense (sclerotic) and separate from the intact jaw bone. These are called sequestra.
- In some instances, there is formation of new bone at the margins, which is called involucrum.
- The process of bone death and remodelling leads to areas of radiolucency and radiopacity, which is typically described as a "moth-eaten" appearance on radiographs.
- Interpretation of advanced imaging modalities should be done only by a certified specialist. In young adults, there may sometimes be subperiosteal new bone formation that appears as a thin radiopaque line along the lower border of the mandible, which gives "onion skin" appearance (Garré osteomyelitis).
- Occasionally, in children and young adults, sclerosis of bone occurs around the site of periapical or periodontal infection instead of bone destruction. This is due to low-grade periapical infection or strong host defense. There is localized uniform density related to the tooth with a widened periodontal ligament or periapical space.
- Both clinical and radiographic features should be assessed while establishing a diagnosis or during follow-up after treatment. In initial stages of disease, there may not be any radiographic features (only bone scans will have a positive hot spot). After treatment, bone gradually remodels within 6–12 months, making for persistence radiographic features even after successful treatment.
Based on the patient's history, clinical symptoms and radiographic findings, a diagnosis of osteomyelitis is confirmed.
- Bisphosphonate-related osteonecrosis of the jaw
Common Initial Treatments
- Remove the source of infection (e.g., extract or perform root canal treatment on the offending tooth).
- Prescribe antibiotics: empirical treatment initially, but prescribe specific antibiotics based on culture and sensitivity reports.
- The recommended antibiotic is penicillin V potassium, 500 mg (1 tablet 4 times daily for 7 days).
- Alternatively, prescribe amoxicillin, 500 mg (1 tablet 3 times daily for 7 days) or clindamycin, 150 mg or 300 mg (1 capsule 4 times daily for 7 days).
- For pain control, prescribe analgesics (acetaminophen, 325 mg, 6 times daily). The maximum cumulative dose of acetaminophen is 4 g in 24 hours). Patients may require opioid analgesia if pain is severe (oxycodone 5 mg with acetaminophen 325 mg [Percocet®], 1 tablet 4–6 times daily).
- For severe infections, prescribe amoxicillin/clavulanate potassium (Augmentin®), 500 mg (1 tablet 3 times daily). Consider intravenous antibiotics (penicillin G potassium, 12 million to 24 million units per day, depending on the infection and its severity, administered in equal doses 4–6 times daily). Monitor for seizures, hyperkalemia and renal function at high doses (10 million to 100 million units daily) of penicillin G potassium. Consider hospitalization if there are signs and symptoms of sepsis or airway compromise.
- For anaerobic infections, prescribe clindamycin (Dalacin) 150–300 mg (1 tablet 4 times daily for 10 days). If you suspect that the anaerobes are periodontal in origin, consider a combination of amoxicillin 500 mg with metronidazole 250 mg 3 times daily.
- Advise the patient to maintain local hygiene in areas of exposed bone (chlorhexidine gluconate 0.12%, 20 mL for 30 seconds 3 times daily).
- If the tooth is the source of infection, consider endodontic treatment or extraction (along with bone debridement).
- Extensive involvement may require sequestectomy, decortications, resection and reconstruction of bone, for which referral to an oral surgeon is important.
Educate patients about good oral hygiene.
- Neville BW, Damm DD, Allen CM, Bouquot JE, editors. Oral and maxillofacial pathology. 3rd ed. St. Louis: Saunders Elsevier; 2009.
- White SC, Pharoah MJ. Oral radiology: Principles and interpretation. 6th ed. Mosby; 2008.