ortho - diseases of bone & joint (septic arthritis / osteomyelitis) Flashcards
osteomyelitis def
– inflammation of bone
arthritis
– inflammation of a joint
acute osteomyelitis
- Usually first decade of life
- More common in lower socio-economic groups
- Immune compromise – diabetes, renal disease, HIV
- More common in boys
- Mortality decreased from 50% to less than 1% with antimicrobial therapy
acute osteomyelitis pathogenesis
- metaphysis
– Venous sinusoids
– Slow blood flow
– No cell lining: no capacity to phagocytose
– Vulnerable to minor trauma - Transient bacteraemia
– Skin, concurrent infection, teeth
= Colonization - Oedema
– ↑ tissue tension
– Small infarcts (death of bone) - Pus
– General circulation → Septicaemia
– Medullary cavity → Full length of bone
– Under periosteum → Strips periosteum, ↓periosteal blood supply → further infarction
– Soft tissues → Abscess
bacteriology acute osteomyelitis
1) Staph aureus – commonest in all age groups
2) Streptococcus–immunecompromised
3) Haemophilusinfluenza–infants
4) Gram –ve coliforms – neonates
5) Others
acute osteomyelitis clinical features
- History of trauma
- Pain
- Fever
- Limp, reluctance to bear weight
- Pseudo-paralysis
- Metaphyseal tenderness
- Neighbouring joint swollen, not tense
- Late: Oedema, cellulitis, fluctuation
- Dehydration, ↓consciousness
acute osteomyelitis lab investigations
- WCC ↑
- ESR ↑
- CRP ↑
- Blood cultures
- HIV
- U+E
acute osteomyelitis x-ray investigations
- Initially normal (<10 days)
- Later: Soft tissue swelling, & Periosteal reaction
- Useful to exclude fracture
- Role of bone scan
acute osteomyelitis management
1) Identify organism–blood cultures
2) Resuscitate / correct hydration – ivi fluids
3) Intravenous antibiotics–
* Cloxacillin – all ages
* Ampicillin – infants
* Gentamycin – neonates
* Modify according to culture results
4) Surgical drainage & decompression of bone
5) Splintage and analgesia
6) Oral antibiotics x 6 weeks
acute osteomyelitis complications
1) Chronic osteomyelitis
2) Growth plate damage→ limb length discrepancy or angular deformity
chronic osteomyelitis pathology
- Usually a sequel to acute osteomyelitis
- Extensive ischaemia in the acute stage:
– Dead bone → Sequestrum
– New bone → Involucrum - Chronic sinuses
- Flare-up of acute infection / abscess
chronic osteomyelitis x-ray
- Thickened bone, loss of normal architecture
- Areas of sclerosis and translucency – moth-eaten appearance
- Sequestrum
- Involucrum
chronic osteomyelitis rx
- Debridement and sequestrectomy
- Lautenbach irrigation – system of tubes laid within bone to instill correct antibiotic directly to bone
- ? Bone graft
chronic osteomyelitis complications
- Extensive ischaemia → no new bone formation
- Pathologic fractures with non union
- Flare-up of acute infection, abscess
- Growth disturbance
- Difficult to eradicate
acute septic arthritis pathology
- Infection from: blood stream or 2° from adjacent bone
- Synovitis → fluid rich in polymorphs in joint
- Proteolytic enzymes → destruction of cartilage
acute septic arthritis clinical features
- Pain
- Limp
- Pyrexia
- Tense swelling of joint
- ↓↓↓Movement of joint (protective muscle spasm)
acute septic arthritis x-ray
- Widened joint space (sometimes)
- Exclude fracture
acute septic arthritis differential diagnosis
RATTTHO
- Trauma
- Tumour
- Tuberculosis
- Acute rheumatic fever
- Rheumatoid arthritis
- Osteomyelitis
- Haemarthrosis / haemophilia
acute septic arthritis rx
- Same as acute osteomyelitis but with arthrotomy
- Splintage to prevent contracture
- Physio to rehabilitate joint
tuberculosis pathology
- Primary complex – lung or gut
- Secondary spread – with ↓ resistance
- Tertiary lesion – eg in bone or joint
- Giant cells coalesce → destruction of normal tissue and formation of caseous material
TB general clinical feutures
- Gradual onset
- Lassitude, ↓ appetite
- Night sweats
- Loss of weight
joint TB clinical features
- Pain, swelling, limp – gradual onset
- Synovial thickening, effusion, warm joint
- ↓ Movement
joint TB x-ray
- Rarefaction of bone
- Erosion of cartilage
- Joint space narrowing
joint TB rx
- TB drugs – INH, Rifampicin, PZA for 9 months
- Treat complications
- Fibrous ankylosis Deformity, Contractures
= Osteotomies, arthrodeseis
TB spine pathology
- Bacilli settle in vertebral body
- Vertebral body collapses
►Kyphosis
►Caseous material or bone compresses cord
►Neurology
TB spine clinical features
- Back pain
- Lump (kyphos or gibbus)
- Neurology- paraesthesias, weakness, paraplegia
TB spine x-ray
- Destruction of vertebral body
- Narrowed disc space
- Paravertebral abscess
TB spine rx
1) Eradicate disease:
TB drugs
+/- Surgical debridement
2) Prevent or correct deformity:
Bracing
Spinal fusion
3) Prevent paraplegia
TB spine early onset paresis
- 80% recover
- Due to abscess or bone sequestrum
TB spine late onset paresis
• Due to: ↑Deformity, Re-activation & Cord ischaemia
• Prognosis less favourable
