Infection in bones and joints

Question 1

sources of infection in acute osteomyelitis

Answer 1

heamatogeous spread 
local spread (trauma, bone surgery) 
secondary to vascular insufficiency 
infected umbilical cord 
boils, tonisilits, skin abrasion 
UTI, arterial line

Question 2

diseases commonly associated with acute osteomyelitis in adults

Answer 2

rheumatoid arthritis 
immunocompromised 
diabetes
long-term steroid treatment 
sickle cell disease

Question 3

causative organisms of acute osteomyelitis

Answer 3

infants: staph aureus, E.coli, group B streptococci
children: heamophilus influenzae, staph aureus, strep pyogenes
adults: staph a, pseudomonas aeruginosa, mycobacterium tuberculosis, coagulase -ive staphylococci

Question 4

pathological process of acute osteomyelitis

Answer 4

starts at metaphysis
vascular stasis (venous congestion + arterial thrombosis) 
acute inflammation (increased pressure)
pus formation 
release of pressure - pus rupture
necrosis of bone (sequestrum) 
new bone formation 

resolution or not (chronic osteomyelitis)

Question 5

clinical features of acute OM in infants

Answer 5

failure to thrive
drowsy, irritable
decreased ROM
metaphyseal tender and sowllen

Question 6

clinical features of acute OM in children

Answer 6

severe pain 
reluctant to move + bear weight 
swinging pyrexia 
tachycardia 
fatigue, nausea + vomit

Question 7

acute OM investigations

Answer 7

FBC and differentiated WCC 
CRP, ESR 
U+Es
blood cultures x3 (at peak of temp)
x-ray 
USS 
x-ray 
aspiration 
isotope bone scan 
labelled white cell scan 
MRI

Question 8

treatment of acute OM

Answer 8

support for pain and dehydration
rest and splintage
antibiotics (flucloxacillin + benzylpenicillin whilst wait culture result)
surgery

Question 9

indications for surgery in acute OM

Answer 9

aspiration of pus for diagnosis and culture
abscess drainage
debridement of dead/infected/contaminated tissue

Question 10

complications of acute OM

Answer 10

septicaemia, death 
metastatic infection 
pathological infection 
septic arthritis 
altered bone growth 
chronic osteomyeltiis

Question 11

how may chronic OM start

Answer 11

following acute OM
de novo: following open surgery, immunocompromised, diabetic, elderly
repeated breakdown of ‘healed wounds’

Question 12

complications of chronic OM

Answer 12

chronic discharging sinus + flare-up
ongoing infection (abcess) 
pathological fracture 
growth disturbance and deformity 
squamous cell carcinoma

Question 13

treatment of chronic OM

Answer 13

long term antibiotics

surgery

Question 14

route of infection with septic arthritis

Answer 14

heamatogenous
eruption of bone abcess
direct invasion e.g. penetrating wound

Question 15

organisms with septic arthritis

Answer 15

staph. a
heamophilus influenzae
streptococcus pyogenes
e.coli

Question 16

treatment of septic arthritis

Answer 16

general supportive
antibiotics (3-4wks)
surgical drainage and lavage (emergency)
infected joint replacements

Question 17

classification of bone + joint TB

Answer 17

extra-articular
intra-articular
vertebral body

Question 18

clinical features of bone + joint TB

Answer 18

insidious onset and general ill health 
low grade pyrexia 
contact w TB  
pain (esp at night) 
swelling
weight loss
decreased ROM

Question 19

bone + joint TB investigations

Answer 19

mantoux 
sputum/urine culture 
FBC
ESR
x-ray 
joint aspiration and biopsy

Question 20

septic arthritis features

Answer 20

hot, swollen, acutely painful joint
acute synovitis and purulent joint effusion
destruction articular cartilage

Question 21

septic arthritis sequelae

Answer 21

complete recovery

partia loss artic cartilage –> OA