Acute Osteomyelitis Flashcards
What is Osteomyelitis
Osteomyelitis (OM) is an infection of bone.
What is epidiemiology of osteomyelitis
Mostly children (different ages)
Boys > girls
History of trauma (minor)
What are disease associated with ostemyelitis
- diabetes, rheum arthritis, immune compromise, long-term steroid treatment, sickle cell (very specific type)
What is the source of infection in infants for osteomyelitis
- Infected umbilical cord
What is the source of infection in children for osteomyelitis
- Haematogenous spread
- Boils
- Tonsillitis
- Abrasions
What is the source of infection in adults for osteomyelitis
Local spread from contiguous site of infection
Trauma (open fracture), bone surgery (ORIF), joint replacement
Secondary to vascular insufficiency
UTI
Arterial line
What is the source of infection in the elderly for osteomyelitis
Haematogenous spread
What is the main bacteria that causes osteomyelitis
Staph aureus
What are common organisms that cause osteomyelitis in infants
Staph aureus, Group B streptococci, E. coli
What are common organisms that cause osteomyelitis in older children
Staph aureus, Strep pyogenes, Haemophilus influenzae
What are common organisms that cause osteomyelitis in adults
Staph Aureus
Coagulase negative staphylococci (prostheses),
Propionibacterium
Mycobacterium tuberculosis
Pseudomonas aeroginosa
What are some rarer special cases of infection for osteomyelitis
Diabetic foot and Pressure sores - mixed infection including anaerobes
Sickle cell disease – Salmonella spp
Mycobacterium marinum (fishermen, filleters (seal bites)
Candida (debilitating illness, HIV AIDS) – very difficult to eradicate
Where do you see acute osteomyelitis?
Long bones
- distal femur
- proximal tibia
- proximal humerus
Joints with intra-articular metaphysis
- hip
- elbow (radial head)
What is the pathophysiology of osteomyelitis in long bone
- starts at metaphysis – role of trauma?
- vascular stasis
o (venous congestion + arterial thrombosis) - acute inflammation – increased pressure
- suppuration (puss formed)
- release of pressure (rupture of boil/absess)
o (medulla, sub-periosteal, into joint) - necrosis of bone (sequestrum) – due to damage to blood supply/the infection
- new bone formation (involucrum)
- resolution - or not (chronic osteomyelitis
What are clinical features of osteomyelitis in infants
- May be minimal signs, or may be very ill Failure to thrive - Poss. drowsy or irritable - Metaphyseal tenderness + swelling - Decrease ROM - Positional change (eg may be flexed) - Commonest around the knee - Often multiple sights
What are clinical features of osteomyelitis in children
- Severe pain (will complain)
- Reluctant to move (neighbouring joints held flexed); not weight bearing
- May be tender fever (swinging pyrexia) + tachycardia
- Malaise (fatigue, nausea, vomiting – “nae weel” - fretful
- Toxaemia
What are clinical features of primary osteomyelitis in adults
- Primary OM seen commonly in thoracolumbar spine
- Backache and evidence of sepsis
- History of UTI or urological procedure
- Elderly, diabetic, immunocompromised
What are clinical features of Secondary osteomyelitis in adults
- Often after open fracture, surgery (esp. ORIF)
- Mixture of organisms
What will be elevated in bloods from a patient with osteomyelitis
ESR
CRP
When do you take blood cultures from a patient with osteomyelitis
At peak of temperature
What investigations should you do for a patient with osteomyelitis
X-ray Ultrasound Aspiration Isotope bone scan Labelled white cell scan MRI
What is to note about xraying for osteomyelitis
normal in the first 10-14 days)
- Early on in infection the organisms breeding in the bone will not show any change until the bone itself has been changed
What does an ultrasound look for in osteomyelitis
- Looks for fluid (any ruptured puss)
What does isotope bone scan look for and what contrasts are used
- Highlights areas of increased bone turnover
Tc-99, Gallium-67 (contrast
