Joint and Bone Infection Flashcards
What are some sources of infection for osteomyelitis?
Haematogenous spread
Secondary to vascular insufficiency
Local spread of infection from open fracture, bone surgery or joint replacement.
Infected umbilical cord
In children: boils, tonsillitis, skin abrasions
In adults: UTI, arterial line
In what types of patients does osteomyelitis usually present?
Children after trauma
Elderly are more prone to chronic osteomyelitis
Immunocompromised, sickle cell disease, rheumatic arthritis and diabetics
What are the causative organisms of osteomyelitis in the different patient groups?
Infants <1 year: Staph aureus, Group B streptococci, E. coli
Older children: Staph aureus, Strep pyogenes, Haemophilus influenzae
Adults: Staph aureus, coagulase negative staphylococci (prostheses), Propionibacterium spp (prostheses, Mycobacterium tuberculosis, Pseudomonas aeruginosa (esp. secondary to penetrating foot injuries as this colonises the soles of shoes)
Diabetic foot and Pressure sores - mixed infection including anaerobes
Sickle cell disease – Salmonella spp
Mycobacterium marinum (fishermen, filleters)
Candida (debilitating illness, HIV AIDS)
In what area of the bones does osteomyelitis most commonly present?
At the metaphysis of the bone-distal femur, proximal tibia, proximal humerus
Joints with intra-articular metaphysis-hip, elbow (radial head)
What are the clinical features of OM in an infant?
May be minimal signs, or may be very ill Failure to thrive Drowsy or irritable Metaphyseal tenderness and swelling Decrease ROM Positional change Commonest around the knee
What are the clinical features of OM in a child or adult?
Severe pain Reluctant to move (neighbouring joints held flexed) Not weight bearing May be tender fever (swinging pyrexia) Tachycardia Malaise (fatigue, nausea, vomiting) Toxaemia Primary OM seen commonly in thoracolumbar spine so get backache History of UTI or urological procedure Elderly, diabetic, immunocompromised
What investigations should be done for acute OM?
FBC WBC Xray MRI Aspiration US CT ESR, CRP Blood cultures x3 U&Es Isotope Bone Scan Labelled White cell scan Bone Biopsy Tissue swabs from surgery
What are the differential diagnoses for acute OM?
Acute septic arthritis Acute inflammatory arthritis Trauma (fracture, dislocation, etc.) Transient synovitis (“irritable hip”) Sickle cell crisis Gaucher’s disease Rheumatic fever Haemophilia
What are sequestrum and involucrum?
Late osteonecrosis - sequestrum
Late periosteal new bone-involucrum
What is the management of acute OM?
Supportive care-fluids, analgesia and rest/splintage
IV antibiotics at start then can change to oral antibiotics, keep on for 4-6 weeks
Surgery sometimes needed
When is surgery indicated in acute OM?
Aspiration of pus for diagnosis & culture
Abscess drainage (multiple drill-holes, primary closure to avoid sinus)
Debridement of dead/infected /contaminated tissue
What are the complications of acute OM?
Septicaemia Death Metastatic infection Pathological fracture Septic arthritis Altered bone growth Chronic osteomyelitis
How can chronic OM be brought on?
May follow acute osteomyelitis May start de novo Following operation Immunosuppressed, diabetics, elderly, drug abusers, etc. Repeated breakdown of “healed” wounds
What are some complications of chronic OM?
Chronically discharging sinus + flare-ups
Ongoing (metastatic) infection (abscesses)
Pathological fracture
Growth disturbance and deformities
Squamous cell carcinoma
What is the management of chronic OM?
Long-term antibiotics-local (gentamicin) Eradicate bone infection- surgically Treat soft tissue problems Deformity correction Amputation
