Bone and Joint Infections Flashcards
Which groups of patients are most likely to get acute osteomyelitis?
- Children
- Boys>girls
- History of trauma
- Other disease: diabetes, RA, immune compromise, long term steroids and sickle cell
What are the common routes of infection in acute osteomyelitis?
- Haematogenous spread (children and elderly)
- Local spread from contiguous site of infection: trauma, bone surgery and joint replacement
- Secondary to vascular insufficiency
What are the common sources of infection in acute osteomyelitis?
- Infants: infected umbilical cord
- Children: boils tonsillitis and skin abrasions
- Adults: UTI and arterial lines
What are the common organisms that cause acute osteomyelitis?
- Infants <1yr: Staph aureus, Group B strep and E. coli
- Children: Staph aureus, Strep pyogenes and H. influenzae
- Adults: Staph aureus
Which organisms can cause acute osteomyelitis in prostheses?
- Coagulase negative staphylococci
- Propionibacterium spp
What are the organisms that can cause acute osteomyelitis in specific groups of people?
- Mycobacterium tuberculosis
- Pseudomonas aeroginosa: IVDAs and penetrating foot injuries
- Mixed infection: diabetic foot and pressure sores
- Salmonella: Sickle cell
- Mycobacterium marinum: fishermen and filleters
- Candida: debilitating illness, HIV/AIDs
Which locations are most common for acute osteomyelitis?
- Long bones: distal femur, proximal tibia and proximal humerus
- Joints with intra-articular metaphysis: hip and elbow (radial head)
Describe the steps in the process of osteomyelitis
- Starts at metaphysis
- Vascular stasis
- Acute inflamm. (increased pressure)
- Suppuration
- Release of pressure
- Necrosis of bone (sequestrum)
- New bone formation
- Resolution or chronic osteomyelitis
What are the clinical features of osteomyelitis in an infant?
- May be minimal signs or may be very ill
- Failure to thrive
- Possibly drowsy/irritable
- Metaphyseal tenderness + swelling
- Decreased ROM
- Positional change
- Most common around the knee
What are the clinical features of acute osteomyelitis in a child?
- Severe pain
- Reluctant to move; not weight bearing
- Tender, fever, tachycardia
- Fatigue, nausea, vomiting, fretful
- Toxaemia
What are the clinical features of acute osteomyelitis in an adult?
- Primary seen most commonly in the thoracolumbar spine
- Backache
- History of UTI/Urological procedure
- Elderly, diabetic, immunocompromised
- Secondary: commoner, found after open fracture surgery
How can acute osteomyelitis be diagnosed?
- History and Exam: pulse + temp
- FBC + diff WBC (neutrophil leucocytosis)
- ESR &CRP
- Blood cultures x3
- U&Es: ill and dehydrated
What is the differential diagnosis for acute osteomyelitis?
- Acute septic arthritis
- Acute inflammatory arthritis
- Trauma
- Transient synovitis
- Soft tissue infections
- Rare: sickle cell crisis, Gaucher’s disease, rheumatic fever and haemophilia
Which scans can be used to diagnose acute osteomyelitis?
- X-ray
- USS
- Aspiration
- Isotope bone scan
- Labelled white cell scan
- MRI
How can acute osteomyelitis be microbiologically diagnosed?
- Blood cultures: haematogenous osteomyelitis and septic arthritis
- Bone biopsy
- Tissue or swabs from up to 5 sites around implant (prosthetics)
- Sinus tract and superficial swab results may be misleading
What is the treatment for osteomyelitis ?
- Supportive: general care and analgesia
- Rest and splintage
- Antibiotics (4-6 weeks): Fluclox + Benzylpen whilst waiting on lab results
What are the indications for surgery in osteomyelitis?
- Aspiration of pus for diagnosis and culture
- Abscess drainage
- Debridement of dead/infected/contaminated tissue
- Refractory to non-operative Rx
What are the complications of acute osteomyelitis?
- Septicaemia/death
- Metastatic infection
- Pathological fracture
- Septic arthritis
- Altered bone growth
- Chronic osteomyelitis
What are the causes of the chronic osteomyelitis?
- Acute osteomyelitis
- Operations
- Open fractures
- Immunosuppressed, diabetics, elderly, drug abusers etc.
- Repeated breakdown of healed wounds
Which organisms can cause chronic osteomyelitis?
- Often mixed infection
- Mostly staph aureus, E. coli, strep pyogenes and proteus
Describe the pathology of chronic osteomyelitis
- Cavity and possible sinuses
- Dead bone
- Involcrum
- Chronic inflamm.`
What are the complications of chronic osteomyelitis?
- Chronically discharging sinus + flare ups
- Ongoing infection
- Pathological fracture
- Growth disturbance + deformities
- Squamous cell carcinoma
What is the treatment of osteomyelitis?
- Long term antibiotics (local or systemic)
- Surgery
- Treat soft tissue problems
- Deformity correction?
- Massive reconstruction?
- Amputation?
What are the routes of infection in acute septic arthritis?
- Haematogenous
- Eruption of bone abscess
- Direct invasion: penetrating wound, intra-articular injury and arthroscopy
What are the common organisms that cause acute septic arthritis?
- Staph aureus
- H. influenzae
- E. coli
Describe the pathology of acute septic arthritis
- Acute synovitis with purulent joint effusion
- Articular cartilage attacked by bacterial toxin and cellular enzyme
- Complete destruction of the articular cartilage
What are the clinical features of acute septic arthritis in a neonate?
Picture of Septicaemia:
- Irritability
- Resistance to movement
- Ill
What are the clinical features of acute septic arthritis in a child or adult?
- Acute pain in a single large joint
- Reluctant to move the joint
- Increased temp. and pulse
- Increased tenderness
- Adult: superficial joints (knee, ankle and wrist)
How can acute septic arthritis be investigated?
- FBC, WBC, ESR, CRP and blood cultures
- XR
- USS
- Aspiration
What is the most common cause of acute septic arthritis?
Infected joint replacement - staph aureus infection
Name the differential diagnoses of acute septic arthritis?
- Acute osteomyelitis
- Trauma
- Irritable joint
- Haemophilia
- Rheumatic fever
- Gout
- Gaucher’s disease
What is the treatment of acute septic arthritis?
- General supportive measures
- Antibiotics (3-4 weeks)
- Surgical drainage and lavage
What are the classifications of TB in bones and joints?
- Extra-articular (epiphyseal/ bones with haemodynamic marrow)
- Intra-articular (large joints)
- Vertebral body
What are the clinical features of TB in bones and joints?
-Insidious onset and general ill health
-Contact with TB
Pain (esp. at night), swelling and loss of weight
-Low grade pyrexia
-Joint swelling
-Decreased ROM
-Ankylosis
-Deformity
Describe the pathology of TB
- Primary complex (lung or gut)
- Secondary spread
- Tuberculous granuloma
What are the features of tuberculosis in the spinal?
- Little pain
- Present with abscess or kyphosis
Which features are diagnostic of tuberculosis in bones or joints?
- Long history
- Involvement of single joint
- Marked thickening of the synovium
- Marked muscle wasting
- Periarticular osteoporosis
How can TB in bones/joints be investigated?
- FBC, ESR
- Mantoux test
- Sputum/urine culture
- XR (soft tissue swelling, periarticular osteopaenia and articular space narrowing)
- Joint aspiration and biopsy
Name the differential diagnosis of TB in bones/joints
- Transient synovitis
- Monoarticular RA
- Haemorrhagic arthritis
- Pyogenic arthritis
- Tumour
What is the treatment of TB in bones/joints?
- Rifampicin, Isoniazid and ethambutol for 8 weeks
- Rifampicin and Isoniazid for 6-12 months
- Rest and splintage
