Definition
- Osteomyelitis is an acute or chronic inflammation of the bone due to an infection resulting from hematogenous spread, contiguous spread from soft tissues & joints to bone, or direct inoculation into bone from surgery or trauma
- Infection is generally due to a single microorganism but polymicrobial infections may also occur
Nguyên nhân
Staphylococcus aureus is the most common cause of acute or chronic hematogenous osteomyelitis in children & adults
Common Pathogens in Osteomyelitis
Acute Hematogenous Osteomyelitis (AHO)
- S aureus is the most common etiologic agent in children & adults
- Children w/ community-acquired Methicillin-resistant S aureus (CA-MRSA) infection are more likely to have prolonged fever & be hospitalized for longer periods than children infected w/ Methicillin-sensitive S aureus (MSSA)
- Children w/ Methicillin-resistant S aureus infection are more likely to have multiple foci of infection as well as subperiosteal & intraosseous abscesses
- Other causes of acute hematogenous osteomyelitis in children include Streptococcus pneumoniae, S pyogenes, Kingella kingae; rarely, Escherichia coli & other gram-negative enteric bacilli, Pseudomonas aeruginosa, Haemophilus influenzae type B, anaerobes
- IV drug abusers are more prone to infections by P. aeruginosa, Serratia marcescens, S aureus, Salmonella spp & fungal organisms
- Fungi may be the cause of osteomyelitis in neonates, patients who are immunocompromised eg w/ prolonged neutropenia, those w/ chronic granulomatous disease, catheter-related fungemia, or are in geographic locations indigenous for certain fungal diseases
Contiguous-Infection Osteomyelitis
- Among patients w/o generalized vascular insufficiency, S aureus is most frequently isolated from bone, but multiple pathogens may also be isolated including gram-negative bacilli & anaerobes
- Among patients who have generalized vascular insufficiency, esp those w/ DM, multiple pathogens are usually isolated from bone, most commonly coagulase-positive & negative staphylococci,Streptococcus spp, Enterococcus spp, gram-negative bacilli & anaerobes
- Anaerobic organisms are common in patients w/ risk factors including surgery, trauma, DM, decubitus ulcers, human bites, chronic otitis media or sinusitis, dental infection, prosthetic devices, fibrous dysplasia of the bone
Vertebral Osteomyelitis
- S aureus is the most frequently isolated pathogen
- Spondylitis is the most common form of Mycobacterium tuberculosis musculoskeletal infection & should be suspected if symptoms & x-rays indicate chronic infection
- E coli may be an etiologic agent in adults esp those w/ a history of recent urinary tract infection or instrumentation
- IV drug abusers are more prone to infections due to P aeruginosa, S aureus, Serratia spp, Klebsiellaspp, Enterobacter spp, or Candida spp
Signs and Symptoms
- Fever
- Inflammatory findings of erythema, warmth, pain, & swelling over the involved area
- Draining sinus tracts over affected bone
- Limited movement of affected extremity
- Pain in the chest, back, abdomen or leg, & tenderness over involved vertebrae in patients w/ vertebral osteomyelitis
- Anorexia, vomiting, malaise
Yếu tố nguy cơ
- Chronic wounds w/ exposed bone, tissue necrosis, underlying open fractures or underlying internal fixation
- Advanced age
- Diabetes mellitus (DM)
- Immunosuppression
- IV drug abuse
- Organ transplantation
- Malnutrition
- Cancer
- Renal or hepatic impairment
- Chronic hypoxia
- Peripheral vascular disease
- Radiation fibrosis
- Neuropathy
- Tobacco consumption >2 packs/day