Osteomyelitis: Your Guide to Symptoms, Diagnosis, and Treatment

1. 1. Exogenous: most common osteomyelitis in adults
2. Acute osteomyelitis from open fracture or bone exposed at surgery
3. Chronic osteomyelitis from neglected wounds: diabetic feet, decubitus ulcers
4. Hematogenous: most common osteomyelitis in children
5. Pediatric patients
6. Immature immune system
7. Metaphysis or epiphysis of long bones
8. Lower extremity more often than upper
9. Adult patients
10. Immunocompromised (elderly, undergoing chemotherapy transplant recipient)
11. Vertebrae most common adult hematogenous site
12. Patient undergoing dialysis—rib and spine osteomyelitis
13. IV drug abuser—medial or lateral clavicle osteomyelitis
14. Acute osteomyelitis
15. Short duration, usually less than 2 weeks
16. Symptoms include tenderness, limb, refusal to use limb
17. Fever and systemic symptoms variable
18. Laboratory findings:
19. CRP—most sensitive test (increased in ≈97%)
20. Most rapid rise and fall
    —good measure of treatment success
21. ESR—increased in approximately 90%
22. CBC—WBCs increased in only a third
23. Aspiration and biopsy cultures—
    most specific test
24. Histopathology: bony spicules with live osteocytes surrounded by inflammatory cells
25. Treatment
26. 6 weeks of antibiotics directed at specific organisms identified by culture
    Source of Bite | Organism | Primary Antimicrobi Regimen | ---|---|---| Human | Streptococcus viridans(100%)
    Bacteroides spp. (82%)
    Staphylococcus
    epidermidis
    (53%)
    Corynebacterium
    spp. (41%)
    Staphylococcus aureus(29%)
    Peptostreptococcus
    spp.
    Eikenella spp.
    | Early treatment (no amoxicillin/clav (Augmentin)
    With signs of infect ampicillin/sulba cefoxitin, ticarc (Timentin), or p tazobactam
    Patients with penic clindamycin pl ciprofloxacin or trimethoprim/s Eikenella organism clindamycin, na
    metronidazole, first-generation and erythromy to fluoroquinol trimethoprim/s treated with cef ampicillin Dog | Pasteurella canis
    S. aureus Bacteroides spp.
    Fusobacterium
    spp.
    Capnocytophaga
    spp.
    | Amoxicillin/clavula (Augmentin) or (adults); clinda trimethoprim/s (children)
    P. canis is resistant t cephalexin, clin erythromycin
    Antirabies treatme considered
    Only 5% of dog bit become infecte Cat | Pasteurella
    multocida
    | Amoxicillin/clavula cefuroxime axe Table 1.33 Bite Injuries | S. aureus
    Possibly
    tularemia
    | doxycycline Cephalexin should
    P. multocida is resis doxycycline, ce clindamycin; m resistant to eryt
    Of cat bite wounds infected; cultur
    | ---|---|---| Rat | Streptobacillus moniliformis
    Spirillum minus
    | Amoxicillin/clavula doxycycline Antirabies treatme
    indicated Pig | Polymicrobial (aerobes and anaerobes)
    | Amoxicillin/clavulanat generation cephalo ticarcillin/clavulana ampicillin/sulbacta cilastatin Skunk, raccoon, bat | Varies
    | Amoxicillin/clavula doxycycline Antirabies treatme Pit viper (snake) | Pseudomonas spp.
    Enterobacteriaceae
    S. epidermidis Clostridium spp.
    | Antivenin therapy Ceftriaxone Tetanus prophylaxi Brown recluse spider | Toxin
    | Dapsone Catfish sting | Toxins (may become secondarily infected)
    | Amoxicillin/clavulanat
    Adapted from Gilbert DN et al: The Sanford guide to
    antimicrobial therapy, Hyde Park, VT, 2010, Antimicrobial Therapy, p 48.
27. Surgery is reserved for draining abscesses or failure to improve on antibiotics.
28. Subacute osteomyelitis : Brodie abscess 1. Residual of acute osteomyelitis versus hematogenous seeding of growth plate trauma
29. Painful limp with no systemic signs
30. Adolescent to early adult (<25 years)—stronger immune system
31. Localized radiolucency with sclerotic rim at
    metaphysis of long bones
32. Almost exclusively S. aureus (may be lower virulence)
33. Treatment: surgical débridement and 6 weeks of IV antibiotics
34. Rule out tumors (chondroblastoma): “ Biopsy all infections, culture all tumors.”
35. Chronic osteomyelitis
36. History
37. Prior trauma/surgery or soft tissue wound
38. Previous acute osteomyelitis or septic arthritis
39. Should be considered in all nonunions
40. Often chronic wound or draining sinus
41. Laboratory findings
42. Less helpful, can be normal
43. Open bone biopsy/culture best test (sinus tract cultures not helpful)
44. Histopathology
45. Dead bone (avascular) (osteocytes have no nuclei)
46. Fibrosis of marrow space
47. Chronic inflammatory cells
48. Treatment
49. Surgery required for chronic osteomyelitis
50. Basic principles
51. Multiple procedures frequently required
52. Removal of infected hardware
53. Removal of dead bone, which serves as a “foreign object”
54. Débridement of bone until punctate bleeding is restored (“paprika sign”)
55. Débridement of compromised or
    necrotic soft tissue
56. Consideration of preoperative sinus tract injection with methylene blue
57. Consideration of antibiotic spacers: PMMA cement versus biologics
58. Restoration of vascularity or soft tissue muscle coverage
59. Six weeks of antibiotics directed at specific cultures
60. Adequate minimal inhibitory concentration (MIC) of antibiotics at site of infection
61. Host classification (Cierny-Mader; Table 1.34)
62. A: healthy
63. B: wound healing comorbidities
64. BL (local): compromised vascularity

Table 1.34 Chronic Osteomyelitis: Infected Host Types Type Description Risk --- A | Normal immune response; nonsmoker

| Minimal B | Local or mild systemic deficiency; smoker
| Moderate C | Major nutritional or systemic disorder
| High
1. Arterial disease, venous stasis, irradiation, scarring, smoking 4. BS (systemic): compromised immune system
1. Diabetes mellitus, malnutrition, end-stage renal disease, malignancy, alcoholism, rheumatologic diseases, immunocompromised status
1. HIV,
immunosuppressive therapy, DMARDs
5. BL/S (combined local and systemic)
6. C: compromised patient (palliative care or amputation)
1. No quality-of-life improvement if cured
2. Morbidity of procedure exceeds that of the disease.
3. Poor prognosis, poor cooperation with care
7. Anatomic lesion classification ( Fig. 1.50)
1. #### I: medullary—nidus endosteal
1. Residual hematogenous or intramuscular infected nonunion
2. Treatment: unroofing
2. #### II: superficial—infection on surface defect of coverage
1. Full-thickness soft tissue wounds: venous stasis/pressure ulcer
2. Treatment: decortication and soft tissue coverage
3. #### III: localized—cortical infection without loss of stability
1. Infected fracture union with butterfly fragment or prior plate
2. Treatment: sequestrectomy, soft tissue coverage, with or without bone graft
4. #### IV: diffuse—permeative throughout bone, unstable before or after débridement
1. Periprosthetic infection, septic arthritis or infected nonunions
2. Treatment: stabilization, soft tissue coverage, and bone graft
8. Imaging of osteomyelitis
1. Radiographs
1. Acute osteomyelitis
1. Soft tissue swelling (early)

--- FIG. 1.50 Cierny’s anatomic classification of adult chronic osteomyelitis.
2. Bone demineralization or regional osteopenia (≈2 weeks after infection)
2. Chronic osteomyelitis
1. Periosteal reaction, cortical erosions, bony lucency, and sclerotic changes
2. Bony lysis around hardware and prosthetic joints
3. #### Sequestra—dead bone nidus with surrounding granulation tissue
4. #### Involucrum—periosteal new bone forming later
2. #### MRI best method to show early osteomyelitis and anatomic location
1. Penumbra sign
1. Bright signal in surrounding bone
2. Darker abscess and sclerotic bone
2. Negative finding rules out osteomyelitis
3. Positive finding may overestimate extent of disease
3. Fluorodeoxyglucose positron emission
tomography (FDG-PET)
1. Shows malignancies and infections: increased glycolysis
2. Most sensitive test for chronic osteomyelitis
3. More specific than MRI or bone scan
9. Empiric treatment for osteomyelitis prior to definitive culture findings
1. Newborn (up to 4 months of age)
1. S. aureus, gram-negative bacilli, and group B streptococci
1. Nafcillin or oxacillin plus a third-generation cephalosporin
2. If MRSA: vancomycin plus a third-generation cephalosporin
2. Children 4 months of age or older
1. S. aureus and group A streptococci
1. Nafcillin or oxacillin versus vancomycin (MRSA)
2. Immunization has almost eliminated Haemophilus influenzae bone infections.
3. Adults (21 years of age or older)
1. S. aureus
10. Antibiotic spacers/beads
1. Nafcillin or oxacillin versus vancomycin (MRSA)
1. Provide very high antibiotic levels at local area
2. 2–4 g per bag (40 g) of cement (>2 g reduces compressive strength)
3. Pouch can be formed and covered with adherent film.
4. Antibiotics must be heat stable.
1. Cephalosporins, aminoglycosides, vancomycin, clindamycin
2. Antibiotics inactivated by heat must be avoided
1. Tetracycline, fluoroquinolones, polymyxin B,
chloramphenicol
5. Antibiotics elute out over 2–6 weeks.
1. Elution increased with
1. Surface area— beads
2. Higher porosity
—vacuum mixing should not be used.
3. Larger antibiotic crystals— cement should be mixed until doughy, then antibiotics added.
4. Atypical or unusual organisms
1. #### Salmonella osteomyelitis—sickle cell
1. Microinfarcts of bone and bowel
2. Spleen dysfunction
3. Bone crisis versus diaphyseal osteomyelitis
2. Pseudomonas osteomyelitis
1. IV drug abuse and osteomyelitis of medial/lateral clavicle
2. Puncture wounds through rubber/synthetic shoes
3. TB osteomyelitis
1. One-third of the world is infected with TB.
2. One-third of TB in pediatric and HIV-positive patients is extrapulmonary.
3. Spine most common: Pott disease (spinal gibbus)
4. One-fourth of extrapulmonary TB is in hips and knees.
5. Often involves bones on both side of joint
4. Fungal osteomyelitis
1. Long-term IV medications or parental nutrition
5. Treatment
1. Immunosuppression by disease or drugs (RA, transplantation)
2. Candida —most common; is part of normal flora
3. Aspergillus —rare in bone
4. Regional varieties—via inhalation or direct inoculation
5. Coccidioides —southwest United States to South America
6. Histoplasma —soil and bird/bat guano, Ohio and Mississippi river valleys
7. Blastomyces —rotting wood, central southeastern United States
8. Cryptococcus —pigeon droppings, northwest United States/Canada
9. Débridement of osteonecrosis, resection of sinuses and/or synovitis
10. Antifungals: amphotericin
1. Chronic regional multifocal osteomyelitis (CRMO) (also chronic nonbacterial osteomyelitis [CNO])
1. Children/adolescents with multifocal bone pain but no systemic symptoms
2. Exacerbations and remissions, more than 6 months of pain
3. Autoinflammatory disease; a diagnosis of exclusion
4. No abscess, fistula, or sequestrum
5. Laboratory findings: WBC count normal; ESR, CRP may be elevated
6. X-rays demonstrate multiple metaphyseal lytic or sclerotic lesions.
7. Whole-body spin tau inversion recovery (STIR) MRI more sensitive
8. Culture results negative—antibiotics do not help
9. Histologic findings
1. Early: PMNs and osteoclasts
2. Later: lymphocytes, fibrosis, and reactive bone
1. Especially in the