Osteomyelitis, osteoradionecrosis and MRONJ Flashcards
What is osteomyelitis?
Infection of bone
Pathological definition - inflammation of bone marrow
Results in necrosis of an area of affected bone and can be suppurative (pus)
What is the aetiology of osteomyelitis?
Underlying disorders (DM, EtOH, immunosuppressed)
Peri-implantitis
Infected cyst
Surgical wound
Seeding bacteria from other body sites
Rare cause: syphilis or tuberculosis
What are risk factors for osteomyelitis?
- fibrous dysplasia
- previous radiation bone exposure
- osteoporosis
- Paget’s
- bone tumours
- Immunocompromised
What is the mechanism of osteomyelitis?
Bacteria (strep/staph) into marrow space - increased vascular collapse and venous stasis - ischaemia - increased pressure and compromised blood supply - necrosis of bone
After necrosis of bone what can happen?
1) sequestration (little bits of bone expelled slowly)
2) new bone (involucrum)
3) resorption
Where is the most common site for osteomyelitis to occur?
Mandible
Cancellous bone more likely to become ischaemic
Blood supply to mandible less oxygenated than maxilla
What is the microbiology of osteomyelitis?
- Viridans streptococcus
- Anaerobes (prevotella, fusobacterium, peptostreptococcus)
- Staph aureus
- Empirical antibiotic therapy until you get swab results back
Symptoms of osteomyelitis
- deep intense pain
- high intermittent fever
- identifiable causative tooth
- +/- malaise, headache, reduced appetite
- minimal swelling
- no flatulae
- infection usually well localised if treated
Signs of osteomyelitis
- Purudent discharge erodes bone, pus, extensive firm swelling, warm and erythematous.
- Throbbing jaw pain
- severse tenderness
-extrusion of teeth - nerve involvement - altered sensation in trigeminal nerve
What are the symptoms of chronic osteomyelitis?
- normal temp
- symptoms resolve/disappear
- teeth locally are tender
Imaging - moth eaten appearance/sequestrum of bone - involucrum - new bone appearance
- risk of path fracture - higher in edentate mandible
What imaging is appropriate for osteomyelitis?
- OPG - little value in acute phase, treat as OM if you suspec
Chronic - increased radiolucency, moth eaten appearance, islands of bone/sequestra
CT/MRI - sometimes more useful - increased attenuation in medullary cavity, destruction of cortical bone and proliferation of bony tissue.
What is the tx for osteomyelitis?
High dose penicillin sometimes IV
+/- metronidazole
Clindamycin - penetrates avascular tissue but risk of C diff
Surgery
- remove cause
Sequestrectomy - improves blood supply, allow adequate penetration of antibiotics, maximises host defence mechanism.
- hyperbaric oxygen - increase in oxygen helps in angiogenesis and improves osteogenesis and stimulates growth factors.
What are the differences between osteomyelitis and alveolar osteitis?
- OM spreads through bone and is not self limiting
- OM much more chronic
- Represents failure of normal defence
If in doubt biopsy - sockets should have healed by 8 weeks
