Infection in Bones and Joints Flashcards
Acute osteomyelitis
- new infection of bone
- mostly children
- boys > girls
- history of trauma (minor)
- other disease
- diabetes, rheumatoid arthritis, immune compromised, long-term steroid treatment, sickle cell
Acute osteomyelitis-source of infection
- haematogenous spread – children and elderly
- local spread from contiguous site of infection – trauma (open fracture), bone surgery (ORIF), joint replacement
- secondary to vascular insufficiency
Acute osteomyelitis-organisms in infants <1year
- Staph aureus
- Group B streptococci
- E. coli (especially <1 month)
Acute osteomyelitis-organisms in older children
- Staph aureus
- Strep pyogenes
- Haemophilus influenzae
Acute osteomyelitis-organisms in adults
- Staph aureus
- coagulase negative staphylococci (prostheses)
- Propionibacterium spp (prostheses)
- Mycobacterium tuberculosis
- Pseudomonas aeroginosa (esp. secondary to penetrating foot injuries, IVDAs)
Acute osteomyelitis-organisms in diabetic foot and pressure sores
-mixed infection including anaerobes
Acute osteomyelitis-organisms in sickle cell disease
-salmonella spp
Acute osteomyelitis-organisms in fisherman, filliters
-mycobacterium marinum
Acute osteomyelitis-organisms in AIDS
-Candida
Acute osteomyelitis pathology
- starts at metaphysis
- vascular stasis (venous congestion + arterial thrombosis)
- acute inflammation – increased pressure
- suppuration
- release of pressure (medulla, sub-periosteal, into joint)
- necrosis of bone (sequestrum)
- new bone formation (involucrum)
- resolution - or not (chronic osteomyelitis)
Acute osteomyelitis clinical features - infant
- may be minimal signs, or may be very ill
- failure to thrive
- possibly drowsy or irritable
- metaphyseal tenderness and swelling
- decreased ROM
- positional change
- commonest around the knee
Acute osteomyelitis clinical features - child
- severe pain
- reluctant to move (neighbouring joints held flexed); not weight bearing
- may be tender fever (swinging pyrexia) + tachycardia
- malaise (fatigue, nausea, vomiting)
- toxaemia
Acute osteomyelitis clinical features - adult
- Primary OM seen commonly in thoracolumbar spine
- backache
- history of UTI or urological procedure
- elderly, diabetic, immunocompromised - Secondary OM much more common
- often after open fracture, surgery (esp. ORIF)
- mixture of organisms
Acute osteomyelitis initial investigations
- FBC + diff WBC (neutrophil leucocytosis)
- ESR, CRP
- blood cultures x3 (at peak of temperature – 60% +ve)
- U&Es
- X-ray (normal in the first 10-14 days)
- ultrasound
- aspiration
- isotope Bone Scan (Tc-99, Gallium-67)
- labelled white cell scan (Indium-111)
- MRI
Acute osteomyelitis differential diagnosis
- acute septic arthritis
- acute inflammatory arthritis
- trauma (fracture, dislocation, etc.)
- transient synovitis (“irritable hip”)
- soft tissue infection
- cellulitis
- erysipelas - superficial infection with red, raised plaque (Gp A Strep)
- necrotising fasciitis
- gas gangrene
- toxic shock syndrome
Acute osteomyelitis diagnostic investigations
- X-ray (normal in the first 10-14 days)
- ultrasound
- aspiration
- isotope Bone Scan (Tc-99, Gallium-67)
- labelled white cell scan (Indium-111)
- MRI
Acute Osteomyelitis Radiographs
- early radiographs minimal changes
- 10-20 days early periosteal changes
- medullary changes - lytic areas
- sequestrum - late osteonecrosis
- involucrum - late periosteal new bone
Acute osteomyelitis treatment
- supportive treatment for pain and dehydration
- rest & splintage
- antibiotics
- route (IV/oral switch – 7-10 days?)
- duration (4-6 wks – depends on response, ESR) - surgery
Acute osteomyelitis indications for surgery
- aspiration of pus for diagnosis & culture
- abscess drainage (multiple drill-holes, primary closure to avoid sinus)
- debridement of dead/infected /contaminated tissue
- refractory to non-operative Rx >24..48 hrs
Acute osteomyelitis myelitis complications
- septicemia, death
- metastatic infection
- pathological fracture
- septic arthritis
- altered bone growth
- chronic osteomyelitis
Chronic osteomyelitis cause
- may follow acute osteomyelitis
- may start de novo
- following operation
- following open fracture (possibly many years earlier)
- immunosuppressed, diabetics, elderly, drug abusers, etc.
Chronic osteomyelitis organism
- often mixed infection
- usually same organism(s) each flare-up
- mostly Staph. Aureus, E. Coli, Strep. pyogenes, Proteus
Chronic osteomyelitis complications
- chronically discharging sinus + flare-ups
- ongoing (metastatic) infection (abscesses)
- pathological fracture
- growth disturbance + deformities
- squamous cell carcinoma (0.07%)
Chronic osteomyelitis treatment
- long-term antibiotics
- local (gentamicin cement)
- systemic (orally/ IV) - eradicate bone infection- surgically (multiple operations)
- treat soft tissue problems
- deformity correction
- massive reconstruction
- amputation
Acute septic arthritis pathology
- acute synovitis with purulent joint effusion
- articular cartilage attacked by bacterial toxin and cellular enzyme
- complete destruction of the articular cartilage
Acute Septic Arthritis Sequelae
-complete recovery or -partial loss of the articular cartilage and subsequent OA or -fibrous or bony ankylosis
Acute Septic Arthritis Organism
- Staphylococus aureus
- Haemophilus influenzae
- Streptococcus pyogenes
- E. coli
Acute Septic Arthritis Neonate Presentation
- picture of septicaemia
- irritability
- resistant to movement
Acute Septic Arthritis Child/Adult Presentation
- Acute pain in single large joint
- reluctant to move the joint (any movement)
- increase temperature and pulse
- increase tenderness
Acute septic arthritis investigations
- FBC, WBC, ESR, CRP, blood cultures
- X ray
- ultrasound
- aspiration
Acute septic arthritis differential diagnosis
- acute osteomyelitis
- trauma
- irritable joint
- haemophilia
- rheumatic fever
- gout
- Gaucher’s disease
Acute Septic Arthritis Treatment
- general supportive measures
- antibiotics (3-4 weeks)
- surgical drainage & lavage
Tuberculosis Bone and Joint Classification
- extra-articular (epiphyseal / bones with haemodynamic marrow)
- intra-articular (large joints)
- vertebral body
Tuberculosis Clinical Features
- insidious onset & general ill health
- contact with TB
- pain (esp. at night), swelling, weight loss
- low grade pyrexia
- joint swelling
- decreased ROM
- ankylosis
- deformity
Tuberculosis pathology
- primary complex (in the lung or the gut)
- secondary spread
- tuberculous granuloma
Spinal tuberculosis presentation
- little pain
- present with abscess or kyphosis
Tuberculosis investigations
- FBC , ESR
- Mantoux test
- Sputum/ urine culture
- X-ray
- soft tissue swelling
- periarticular osteopaenia
- articular space narrowing - Joint aspiration and biopsy
Tuberculosis Differential Diagnosis
- transient synovitis
- monoarticular RA
- haemorrhagic arthritis
- pyogenic arthritis
- Tumour
Tuberculosis treatment
initial -rifampicin
isoniazid 8 weeks
ethambutol
then - rifampicin and isoniazid 6-12 month
-rest and splintage
-operative drainage rarely necessary
