|
Osteomyelitis
OVERVIEW: Osteomyelitis is an acute or chronic infection of the bone and its structures caused most commonly by bacteria and rarely by other microorganisms. This infection may be acquired either by hematogenous, contiguous, or direct inoculation such as trauma or surgery.
System(s) affected: Musculoskeletal
Genetics: There is no genetic predisposition known in this disease
Incidence/Prevalence in USA: Uncommon
Predominant age: This infection is commonly seen in older adults; hematogenous is bimodal, also seen in infants and children
Predominant sex: Males > Females
SIGNS AND SYMPTOMS: • Hematogenous long bone infection
(in children with hematogenous osteomyelitis)
• Abrupt onset of high fever
• Irritability
• Malaise
• Restriction of movement of the involved extremity
• Signs of localized inflammation
• Hematogenous vertebral infection
(in adults with vertebral osteomyelitis)
• Illness is insidious and behaves more like a chronic infection
• History of an acute bacteremic episode associated with infection of a specific organ may be found in some patients
• Contiguous and vascular insufficiency associated infection
• Acute constitutional manifestations are seldom seen
• Localized signs and symptoms of inflammation with or without drainage frequently found
• Chronic osteomyelitis
• Non-healing ulcer or draining sinus
• Constitutional symptoms, when present, indicate acute suppurative condition in the bone or surrounding tissues
• Prosthetic device associated infection
• Infection may be acquired either by hematogenous route, or by contiguous foci such as local infection, operative contamination, or postoperative infection
• Acute postoperative infection may present as fever, localized swelling, tenderness, and drainage
• Chronic infection is characterized by joint discomfort, swelling, erythema, and joint dysfunction
CAUSES: • Acute hematogenous osteomyelitis
• Staphylococcus aureus (most common)
• Streptococcus, coagulase negative Staphylococcus, Haemophilus influenzae, and gram negative organisms (less common)
• Vertebral osteomyelitis
• Staphylococcus aureus and gram negative enteric organisms (common)
• Other microorganisms to consider include Mycobacterium tuberculosis, and fungi
• Contiguous focus osteomyelitis and vascular insufficiency osteomyelitis
• Mixed aerobic/anaerobic microorganisms are frequently found
• Prosthetic device infection
• Coagulase negative Staphylococcus, and S. aureus (most common)
• Diphtheroids, and gram negative bacteria (less common)
RISK FACTORS: • Sickle cell disease
• Other conditions which predispose to bone infarcts
• IV drug use
• Hemodialysis
• Local trauma
• Open fractures
• Presence of prosthetic orthopedic implant
• Vascular insufficiency
• Neuropathy
• Diabetes mellitus
DIAGNOSIS DIFFERENTIAL DIAGNOSIS: • Systemic infection from other source
• Aseptic bone infarction
• Localized inflammation or infection of overlying skin and soft tissues
• Neuropathic joint disease
• Fractures
• Gout
LABORATORY: • Definitive diagnosis is made by needle aspiration or bone biopsy and demonstration of the microorganism by culture or histology
• Blood culture may be positive in about 50% of younger patients with acute hematogenous disease
• Leukocyte count is usually elevated in the acute cases, but not in the chronic cases
• Sedimentation rate or c-reactive protein is usually elevated, but non-specific
Drugs that may alter lab results: Antimicrobial agents given before bone culture
Disorders that may alter lab results:
• Cultures from the sinus tract are unreliable because of frequent contamination
• Superficial cultures only helpful in identifying methicillin-resistant S. aureus
PATHOLOGICAL FINDINGS: Inflammatory process of the bone with pyogenic bacteria
SPECIAL TESTS: N/A
IMAGING: • No technique can absolutely confirm or exclude osteomyelitis
• Radiographic - routine x-ray (findings on plain x-ray often delayed for 10-14 days in acute infection)
• Radionuclide (technetium, indium, or gallium) are also useful, but limited by low specificity
• CT with good resolution, artifact may decrease specificity
• MRI excellent, but limited by costs
DIAGNOSTIC PROCEDURES: Needle biopsy or open bone biopsy for bacterial culture (which is the gold standard)
TREATMENT APPROPRIATE HEALTH CARE: Hospitalize the patient with suspected acute osteomyelitis for diagnostic work-up and initial treatment
GENERAL MEASURES: Symptomatic treatment of pain
SURGICAL MEASURES: • Surgical drainage and removal of necrotic tissues are of utmost importance to effect cure
• In patients with vascular insufficiency or severe gangrenous infection, amputation may be the only effective treatment
ACTIVITY: Bedrest and immobilization of the involved bone and joint
DIET: No restriction
PATIENT EDUCATION: Stress need for long-term treatment and follow up
MEDICATIONS DRUG(S) OF CHOICE: These are essentially empiric choices; recommendations based on data from a very small number of studies. Antimicrobial agent/agents based on susceptibility testing and known clinical efficacy. The duration of therapy for acute osteomyelitis should be at least 4-6 weeks. In chronic osteomyelitis, longer duration of therapy may be needed.
• Staphylococcus aureus and coagulase negative staphylococcus: nafcillin 2 g IV q4-6h. Vancomycin 1 g q12h for methicillin resistant Staph.
• Streptococcus spp.: penicillin G 2-4 million units q4h IV
• Enteric gram negative bacilli and Pseudomonas aeruginosa: piperacillin 4 g q4-6h IV, plus aminoglycoside
• Mixed aerobic/anaerobic infection (diabetic foot, bite wound): beta-lactamase inhibitor combination (ticarcillin-clavulanate 3.1 g q6h IV; ampicillin-sulbactam 3 g q6h IV); piperacillin-tazobactam 3.375 g q6h IV
Contraindications: Allergy
Precautions: In patients with renal or hepatic insufficiency, antimicrobial dose may need adjustment
Significant possible interactions: Refer to manufacturer's literature
ALTERNATIVE DRUGS: • Staphylococcus aureus and coagulase negative staphylococcus: clindamycin 600 mg IV q6h, nafcillin 2 g q4h, or cefazolin 1 g q8h IV, or vancomycin 1 g q12h
• Streptococcus spp.: penicillin G 2 million units q4h, cefazolin 1 g q8h IV, or clindamycin 600 mg q6h IV
• Enteric gram negative bacilli and Pseudomonas aeruginosa: ceftazidime 1 g q8h IV or ciprofloxacin [or other quinolone] 750 mg q12h orally.
• Mixed aerobic/anaerobic infection (diabetic foot, bite wound): clindamycin plus third generation cephalosporin or quinolone
• Home therapy often used - consider a simplified antibiotic regimen for outpatient use or oral therapy
• Some published studies recommend use of hyperbaric oxygen (HBO), but none are randomized, controlled trials
FOLLOW UP PATIENT MONITORING: Blood level of antimicrobial agents, serum antibacterial titers, sedimentation rate, repeat plain x-ray to confirm healing
PREVENTION/AVOIDANCE: Avoid further stress and weight bearing until healing
POSSIBLE COMPLICATIONS: • Abscess formation
• Bacteremia
• Fracture
• Loosening of the prosthetic implant
• Postoperative infection
EXPECTED COURSE AND PROGNOSIS: • Cure of osteomyelitis with medical treatment is notoriously unpredictable especially when not accompanied by surgical debridement
• In patients with acute hematogenous osteomyelitis, the prognosis is usually good even without surgery. Cure takes about 6 weeks.
• The prognosis is improved if all infected bone has been removed
MISCELLANEOUS ASSOCIATED CONDITIONS: Listed with Causes
AGE-RELATED FACTORS:
Pediatric: Occurs most often in 5-14 age group and more frequently in boys
Geriatric:
• Vertebral osteomyelitis more common
• Contiguous focus of infection more common
• Vascular insufficiency is most common cause of osteomyelitis in 50-70 age group (usually due to presence of associated conditions)
Others: N/A
PREGNANCY: N/A
SYNONYMS: N/A
ICD-9-CM: 730.0 Acute osteomyelitis
730.1 Chronic osteomyelitis
526.4 Jaw osteomyelitis
376.03 Orbital osteomyelitis
(see
images)
Want to discuss this term? Visit
our forum or our chat
room.
SEE ALSO (Enter the keywords below
into our search box or click on the link):
Ataxia-telangiectasia
Von Hippel-Lindau disease
Tuberous sclerosis
Sturge-Weber disease
|
IE 5.0