Please enable JavaScript.
Coggle requires JavaScript to display documents.
Bone and Joint Infections Redo this - Coggle Diagram
Bone and Joint Infections
Redo this
Types of Infection
Infective Arthritis of Native Joint
Bacterial Arthritis
Bacterial bursitis
Viral arthritis
Osteomyelitis
Acute
Chronic
Orthopaedic Implant Relatd Infection
Prosthetic Joint Infectoin
Septic Arthritis
Inflammatory reaction of the joint space caused by an infectious agent
Major Risk Factors
Rheumatoid arthritis
3-7x overall risk
Advanced age
Diabetes mellitus
Chronic renal failure
Previous joint surgery
Penetrating joint injury
Recreational IVDU
Endocarditis
Immunosuppression
Minor Risk Factors
Joint disease
Gout
Osteoarthritis
Chronic Systemic disease
Collagen vascular disease
Malignancy
Sickle cell disease
Chronic liver disease
Alcoholism
Hypogammaglobulinaemia
Intra-articular injection
Skin disease with or without skin infection
Socioeconomic factors
Mode of Infection
Haematogenous Spread
From bacteraemia due to infective endocarditis
Direct joint inoculation
Traumatic penetrating injury
RTA
Farming
Iatrogenic
Joint injection
Aspiration
Contiguous focus
Adjacent soft tissue or bone infection
eg Septic arthritis of small joints of foot distal to infected diabetic foot ulcer
Pathophysiology
Adherence of organisms to and colonisation of synovial membrane
Bacterial proliferation in synovial fluid
Synovial infection with generation of host inflammaotry response
Purulent inflammation,cartilage destruction, joint space narrowing, bone loss
Pathogens
Gram +
Staph aureus
Coagulase negative staph
Strep pyogenes
Strep pneumo
Strep agalactiae
Other streptococci
Gram -
E. coli
Haemophilus influenzae
Neisseria gonorrhoeae
Neisseria meinigitidis
Pseudomonas aeruginosa
Salmonella species
Other (-) rods
Kingella kingae
Pasteurella spp
Brucella spp
Misc anaerobes
Considerations
Specific Circumstances
Pasteurella multocida after cat bite :cat2:
M. TB causing chronic monoarticular septic arthritis
Polymicrobial flora
Cultures of synovial fluid / blood yiel polymicrobial flora in 10% cases
Unconventional Cultures / Investigations
Mycoplasma hominis
Ureaplasma urealyticum
Borrelia burgdorferi
Tropheryma whipplei
Clinical Features
Joint Considerations
Monoarticular or polyarticular
Acute or chronic
Which joints - large most affected
Unual marks / wounds / bites
Joint Presentations
Swollen
Red
Painful
Hot
Decreased range of movement
Systemic Presentation
Fever
Malaise
Biochemical Results
Raised WCC
Raised CRP
Microbiological Exam of Joint Fluid
Microscopy and Cell Count
Aspirate Synovial fluid leukocyte count >50,000 cells/mm3
Suggestive
Low count does not rule out
Gram stain: Bacteria not expected in joint fluid so (+) results requires action
Microscopy crystals
Culture
May be positive even with no organisms seen of Gram
Fresh specimen - multiple agars in attempt to find any organism
May be improved yield of fastidious organisms if some fluid inoculated into blood cultures at time of sampling
Broads range PCR / 16S rDNA
Potential answer to culture negative infx
Caustion interpreting result
No susceptibility info
Types
Gonococcal arthritis
Sexually active young adults
2 syndromes of joint involvement
Monoarticular arthritis
Disseminated Gonococcal Infx
Major concern - limited tx options
Viral Arthritis
Direct viral infx of synovium or
Indirect through host immune-mediatd responses
Common viruses
Parvovirus B19
Chikungunya
Less Common
Rubella
Mumps
Acute Hep B
HCV
HIV
HTLV-1
Chronic Septic Arthritis
Uncommon
Differential for sub-acute or chronic joint inflammation
Emerging problem in immunocompromised / chronically ill
Steroids may delay diagnosis
Pathogens
Mycobacteria
Fungi
B. burgdorfereo - lyme disease
Tropheryma whippleii - whipple's disease
Treponema pallidum - Tertiary syphilis
Nocardia
Septic Bursitis
Common
Sites
Subcutaneous olecranon bursa
Pre-patellar bursa
Infra-patellar bursa
Causes
Minor trauma
Accidentla percutaneous punctures
Pathogens
Staph
Strep
GNB
Fungi
Symptoms
Swelling
Tenderness
Erythema of bursal sac
MAy have reduced range of movement - joint pain
DD
Differentiate from septic arthritis by aspirating bursa and joint
Investigations
Imaging eg MRI
Treatment
Pathogen directed
Bursectomy for refractory cases
Differential Diagnosis
Acute rheumatoid arthritis
Osteoarthritis
Gout
Pseudogout / Chondrocalcinosis - calcium crystals in joint cartilage
Reactive Arthritis
Osteomyelitis
Infection of the bone
One of the most difficult to treat
Pathology
Progressive bone destruction
Formation of sequestrum (devitalized bone)
New bone (involucrum) may form around ifx site
Affected areas by Age
Children
Often involves metaphysis of long bones
Adults
Spine
Routes of Bone Infection
Haematogenous
Contiguous
with skin / joint
Direct inoculation
Diagnosis
Microbiology essential
Biopsy culture
Histology
Bone biopsy - Gold standard
Blood culture
RisK Factors
Systemic
Malnutrition
Renal / hepatic failure
Diabetes mellitus
Chronic hypoxia
Immune disease
Malignancy
Extremes of age
Immunisuppression
Local
Chronic lymphoedema
Major vessel compromise
Small vessel disease
Venous stasis
Extensive scarring
Radiation fibrosis
Neuropathy
Tobacco use
Clinical Features
Non specific pain on site
+/- Fever, chills, local swelling and erythema
Sinus tract formation over involved bone
Prosthetic Joint Infection
Pathogens
Antibiotic Resistance
Management
