Osteomyelitis Flashcards
what causative organism in common to acute osteomyelitis at all ages
staph aureus
2 common sources of infection in adults
UTI and aterial line
3 common sources of infection in children
boils, skin abrasions and tonsilitis
1 common source of infection in infants (<1y/o)
infected umbilical cord
2 modes of infection spread in osteomyelitis
haematogenous and local (contiguous)
what age groups is haematogenous spread most common
children and the elderly
3 examples of contiguous causes of acute osteomyelitis
cellulitis, open fracture and surgery
infection from candida is most common in what immune disease
HIV AIDS
what occupation are likely to be infected by mycobacterium marinium?
fishermen
common organism in IVDA
pseudomonas aeruginosa
causative organsim of tonsilitis which will cause acute osteomyelitis in children
strep. pyogenes
which part of a long bone is usually the site of infection
metaphysis
two commonly infected joints
hip and and radial head
what is a sequestrum
a piece of dead bone
what is a involucrum
new bone growth outside the existing bone, in this case, outside dead bone
progression of infection and resolution in acute osteomyelitis
in medullary cavity/haversian in cortex –> acute inflammation –> increased pressure –> vascular stasis –> necrosis leading to a sequestrum –> pressure releases into joint –> blood returns to bone –> new bone growth can occur
presentation of acute osteomyelitis in infants under a year
failure to thrive
generally ill, drowsy and irritable
decreased range of movement
tenderness and swelling of bone
most common site of acute osteomyelitis in infants
knee
presentation of acute osteomyelitis in children
severe pain holding neighbouring joints in flexed position not weight bearing fever tachycardia malaise, nausea and vomiting
most common site of primary acute osteomyelitis in adults
thoracolumbar spine
what is Pott’s Disease?
vertebral osteomyelitis from haematogenous spread of tuberculosis
presentation of primary acute osteomyelitis in adults
backache
elderly, diabetic or immunocompromised
history of UTI
presentation of secondary acute osteomyelitis in adults
severe pain fever swelling, red, tender bone pain on movement Hx of open fracture or surgery
what neuro symptom would you expect in someone who has bone infection secondary to diabetes
neuropathy
bloods in acute osteomyelitis
FBC, neutrophils, ESR and CRP
when do changes become visible on X-ray
after about 2 weeks, necrosis and involucrum
Scans you can do for osteomyelitis
x-ray ultrasound mri isotope scan with gallium or technetium labelled WBC scan with indium
how do isotope scans works
show up at infected sites
how many blood cultures do you need to do in haematogenous infection
3
microbiology
blood cultures
bone biopsy
swabs or biospy from surrounding site (up to 5)
5 differential diagnoses
cellulitis, erysipelas, acute septic arthritis, acute inflammatory arthritis and necrotising fasciitis
conservative treaments for acute
analgesia, fluids, rest and splint
how long does antibiotic regimen last in acute osteomyelitis
4-6 weeks
how long does antibiotic regiemen last in chronic osteomyelitis
3-6 months
indications for surgery in acute
drainage pus for diagnosis
drain abscess
debridement
antibiotic regimen in acute
flucloxacillin for 6 weeks (or clindamycin if penicillin allergic) +/- fusidic acid or rifampicin for first 2 weeks.
IV then oral after 2 weeks when they’ve stabilised and inflammatory markers go down
mortality from acute osteomyelitis before antibiotics
70%
5 complications of acute osteomyelitis
septicaemia metastatic infection pathological fracture septic arthritis chronic osteomyelitis
true/false - the same organism is usually the cause of flare-ups in chronic osteomyelitis
true
pattern of progression in chronic osteomyeltis
repeated flare-ups of breakdown of ‘healed’ wounds
appearance of chronic osteomyelitis on histology
chronic inflammation
malignant complication of chronic osteomyelitis
squamous cell carcinoma (0.07%)
true/false - is it appropraite in chronic osteomyelitis to wait for culture and sensitivity results before commencing antibiotic treatment
true - unless severe and imminently life threatning, will reduce resistance and improve outcomes
treatment for chronic osteomyelitis
surgical debridement IV antibiotic for 6 weeks gentamicin cement deformity correction and reconstruction amputation
