Osteomyelitis & Septic Arthritis Flashcards
Osteomyelitis
- acute v chornic disease
osteomyelitis: bone infection
Acute
- presents within a few days/ a few weeks
- there is no visable separation between necrotic and healthy bone
Chronic
- present for months/years: long standing infection
- sequestra: there is a visable separation between necrotic and healthy bone
- sinus tracting: if pathopneumonic for chronic
Nonhematogenous Spread of Osteomyelitis
- Risk Factors
- Microbiology
Risk Factors for non-hem
- poorly healing soft tissue wounds (areas of poor vascularization)
- orthopedic hardware (seeding infection)
- diabetes (poor healing)
- peripheral vascualr disease (poor flow)
- peripheral neuropathy (cant tell when injured)
Microbilogy
- most commonly MRSA and staph aures infections
- coag-negatie staphlococci (staph epidermis)
- gram-neg. bacilli (HeN PeCK, pseudomonas)
Hematogenous Spread of Osteomyelitis
- Risk Factors
- Microbiology
Risk Factors
- endocarditis
- indwelling intravascualr devices (PICC or central lines)
- orthopedic hardware
- IVDU
- hemodialysis
- sickle cell disease
Microbiology
- Staph Aureus ( and MRSA)
- gram negative rods
- pseudomonas aeurginosa
- serratia marcesens
- aspergillus (fungi)
Clinical Signs and Symptoms of Osteomyelitis
- Acute
- Chronic
Acute Symptoms
- gradual onset
- dull pain at the effected site
- movement can make the pain worse
- tenderness, redness, swlling, warmth at the site of infection
- can have systemic; Fever or chills
Chronic Symptoms
- intermittent flares of acute symptoms
- pain, redness, open wounds and sinus tracting at the site
- nonhealing fractures
- hard, gritty bone when debreding
Diagnosis of Osteomylitis
- labs
- imaging
- additional workup
Labs
- CBC: for infection
- ESR/CRP: inflammation markers
Imaging
- MRI is gold standard (with contrast)
Biopsy the site of the BONE!! not the soft tissue
Culture: the blood and the bone for treatment
Treatment of Osteomyelitis (multistep)
Debridement
- removal of necrotic bone
- obtain culutre of bone and surrounding tissue
- remove hardware that it may be coming from (if possible)
Antibiotic Therapy
- IV first then a transition to oral for chronic suppression (6 weeks)
- tailored to cultures; amputation usually will need less abx.
- MRSA coverage, gram - coverage
- **vancomycin + 3rd or 4th generation cephalosporins (ceftriaxone, cefotaxime)
Septic Arthritis
- Etiology
- Risk factors
Etiology
- an infection in the joint space as a result of soft tissue or hematogenous spread of infection
- commonly in areas where there is already joint disease (osteoarthritis)
Risk Factors
- older age
- pre-exisitng joing disease
- recent joint surgery or injection
- skin/soft tissue infection
- IVDU
- indwelling catether
- immunosuppressed
Joint Anatomy & How it correlates to Tissue type found there (3 types of joints)
Fibrous Joints: function as synarthrosis
- they are fixed joints, immoveable
- no joint cavity; collagen connects the two joints together
- example: the joints on the skull: the suture lines!
Cartilaginous Joints: function as Amphiarthrosis
- joints which are attached by hylain cartilage or fibrocartilage on either side
- not movable
Synovial Joints: Diarthrosis
- the main functionig joint within the body
- freely movable joint space
- collagen connects the bones together
- surrounded by a joing capsule: Articular Capsule: made of fiberous connective tissue which attaches to the bone just beyond where the joint space is
- contains synovial fluid secreted by the synovial membrane
- example: knee, hip, elbow,sholder, fingers
Septic Arthritis
Pathophysiology: how does the infection get there
- organism most commonly
- joints affected
Hematogenous Spread
- the most common way the joint is infected
- infection seeds the synovial membrane which has no basement membrane to protect
- direct innoculation: bites, trauma, surgery or direct injection
Organism
- staph aureus in all age groups
Joints affected
- the knee (50%)
- hip
- shoulder (sternoclav. joint in IVDU according to PPP)
Septic Arthritis
Clinical Presentation
Joint Characteristics
- monoarticular
- a swollen, effusion joint
- painful and tender
- warm
- decreased ROM
- inability to bear weight
- cannot tolerate PROM
- constitutional symptoms: fever and chills too
Septic Arthritis
- Work up and Diagnosis
Labs
- CBC : show leukocytosis
- ESR/CRP (CRP def. elevated)
- blood culutres : show hematogenous spread
join aspiration gold standard: needed to make the diagnosis: results of > 50,000 WBC in the fluid
- cloudy, purulent fluid, WBC > 50,000, glucose > 60% of serum and negative string sign (normal fluid will be string-like while infected will be not)
Imaging
- MRI/CT can show show swelling and effusion in the joint space
- joint space widening due to increase fluid build up & bone involvement can be seen on imaging if sus for osteomyelititis
- US can also show the fluid & assist in guiding the needle for aspiration
Septic Arthritis
Treatment
Urgent surgical irrigation and debridement of the joint & IV antibiotics
Surgical Drainage needed when…
- adequate drainage not done by needle aspiration or arthroscopy
- suspected FB and trauma
- persistant effusion despite aspiration
- need serial synovial joint fluid analysis to ensure infection is gone
ANtibiotics
- gram+ cocci (staph) = vancomycin
- garm negative bacilli: 3rd gen ceph (ceftriaxone/cefotaxime) or cover with pseudomonas coverage too
- if gonococcal: IV ceftriaxone
