osteomyelitis

Question 1

aetiology

Answer 1

haematogenous spread from continguous site of infection- trauma, bone surgery, joint replacement

affects children most

can be secondary to vascular insufficiency

infants- infected umbilical cord
children- boils, tonsilitis, skin abrasions
adults- UTI, arterial line

Question 2

organisms that cause

Answer 2

infants- staph A, group B strep, E coli
older children- staph A, strep pyogenes, haemophilus influenza
adults- staph aureus, and others

also-
brucella - butchers
mycobacterium marinum - fishermen, filleters
proteus mirabilis
candida

Question 3

what causes vertebral osteomyelitis

Answer 3

Staph aureus, Tb

Question 4

what causes sickle cell disease

Answer 4

salmonella spp

Question 5

what bones get it

Answer 5

long bones
joints with intra articular metaphysis eg hip, elbow

Question 6

pathology

Answer 6

starts at metaphysis
vascular stasis
acute inflammation
suppuration
release of pressure
necrosis of bone - sequestrum
new bone formation - involucrum
resolution or not (chronic)

Question 7

clinical signs infant

Answer 7

may be minimal signs or may be very ill
failure to thrive
poss drowsy or irritable
decreased ROM
commonest around knee
often multiple sites

Question 8

clinical features- child

Answer 8

severe pain
reluctant to move
fever
tachycardia
malaise

Question 9

clinical features adult

Answer 9

primary seen commonly in thoracolumbar spine
backache
history of UTi or urological procedure
secondary much kore common often after open fracture, surgery

Question 10

investigations

Answer 10

FBC- neutrophil leucocytosis
ESR, CRP
blood cultures 3 x
U+E
X ray normal in first 10-14 days
US to find pus
aspiration
MRI
bone biopsy

Question 11

treatment

Answer 11

general car, analgesia
rest and splintage
antibiotics - empirical. assume staph A or whats most common in area, fluclox and benzylpen while waiting
for 4-6 weeks depending on response and ESR
Iv/oral switch at 7 to 10 days

surgery if aspiration of pus needed, abscess drainage, debridement of dead tissue, infected joint replacement

Question 12

chronic

Answer 12

may follow acute or may start de novo following operation, open fracture, or if immunosuppressed, diabetic, drug user, elderly etc
repeated breakdown of healed wounds
often mixed infection

Question 13

acute osteomyelitis in children complications

Answer 13

Angular deformity of the limb
Chronic localised osteomyelitis with a sinus
Limb length discrepancy
Bacterial endocarditis