Bone infections

Question 1

in what age group and sex is acute osteomyelitis more common in?

Answer 1

children

boys > girls

Question 2

what puts a patient at risk of acute osteomyelitis?

Answer 2

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

Question 3

what are the 3 main sources of infection of acute osteomyelitis?

Answer 3

haematogenous spread from blood born infection
local spread from a contiguous infection
secondary to vascular insufficiency (necrotic distal limb = penetration of skin = organisms enter)

Question 4

what are the main causes of blood born infections which can cause acute osteomyelitis?
(infants, children & adult)

Answer 4

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

Question 5

what is the most common causative organism of acute osteomyelitis?

Answer 5

staph aureus

Question 6

what is the most common causative organism for acute osteomyelitis in drug abusers ?

Answer 6

pseudomonas aeroginosa
(also penetrating foot injuries)

Question 7

what is the most common causative organism for acute osteomyelitis if the patient has sickle cell disease?

Answer 7

salmonella sp.

Question 8

at what part of the bone does osteomyelitis start?

Answer 8

metaphysis

Question 9

what are the medical terms for bone necrosis and bone formation?

Answer 9

necrosis = sequestrum 
formation = involucrum

Question 10

what are the signs of osteomyelitis in infants?

Answer 10

failure to thrive
decreased range of movement
positional change
possibly drowsy, irritable
metaphysical tenderness + swelling

Question 11

where is the commonest site of acute osteomyelitis in an infant?

Answer 11

around the knee

often occurs in multiple sites in infants

Question 12

whats the presentation of acute osteomyelitis in a child?

Answer 12

severe pain 
reluctant to move, not weight bearing, neighbouring joints held flexed
tender
swinging pyrexia
tachycardia
malaise (nausea, vomiting, fatigue)

Question 13

what is the most common primary site of acute osteomyelitis in adults?

Answer 13

thoracolumbar spine

Question 14

what is the most common causative organism of primary acute osteomyelitis in an adult?

Answer 14

staph aureus

Question 15

what investigations would you carry out to diagnose acute osteomyelitis?

Answer 15

history and examination
FBC & WCC
ESR, CRP 
blood cultures (x3) , bone biopsy
U&E
xray
USS
aspiration
isotope bone scan 
labelled white cell scan
MRI

Question 16

what is the treatment duration of acute osteomyelitis?

Answer 16

4-6 weeks depending on the response and ESR

Question 17

what is the treatment for acute osteomyelitis?

Answer 17

supportive i.e. analgesia

rest and splintage

antibiotics i.e. flucloxacillin and benzylpenicillin (empirical awaiting microbiology)

surgery

Question 18

what are the complications of acute osteomyelitis?

Answer 18

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

Question 19

what are the causes of chronic osteomyelitis?

Answer 19

follow acute osteomyelitis
following operation, open fracture
immunosuppressed
repeated breakdown of healed wounds

Question 20

what is the causative organism(s) of chronic osteomyelitis?

Answer 20

staph aureus, e.coli, staph progenies, proteus

Question 21

what are the complications from chronic osteomyelitis?

Answer 21

chronically discharging sinuses + flare ups
ongoing metastatic infection (abscesses)
pathological fracture
growth disturbance + deformities
squamous cell carcinoma

Question 22

what are the different treatment options for chronic osteomyelitis?

Answer 22

long term antibiotics 
- local i.e. gentamicin cements, collatamp
- systemic i.e. oral, IV 
surgery (multiple)
treat soft tissue infections
correct deformity
amputation

Question 23

what are the routes of infection for acute septic arthritis?

Answer 23

haematogenous
eruption of abscess
penetration 
- penetrating wound
- intra-articular injury 
- arthroscopy

Question 24

what are the common causative organisms of septic arthritis?

Answer 24

staph aureus
haemophillus influenzae
strep pyogenes
e.coli

Question 25

what is the pathology in acute septic arthritis?

Answer 25

acute synovitis with purulent effusion articular cartilage is attacked by bacterial toxin and cellular enzyme complete destruction of the articular cartilage

Question 26

what is the sequelae of septic arthritis?

Answer 26

complete recovery partial loss of the articular cartilage and subsequent OA fibrous or bony ankylosis

Question 27

what is the presentation of septic arthritis in children/adults?

Answer 27

acute pain in a single large joint - reluctant to move the joint in any movement - increased temp and pulse - increased tenderness

Question 28

what is the commonest cause of septic arthritis in an adult?

Answer 28

infected joint replacement

Question 29

what is the most common causative organism that causes septic arthritis from infected joint replacement ?

Answer 29

staph epidermidisis

Question 30

what is the treatment for acute septic arthritis?

Answer 30

supportive measures antibiotics (if pus then surgical) surgical drainage and lavage 1 or 2 stage revision of infected joint replacement

Question 31

what are the classifications of TB in bone and joints?

Answer 31

extra-articular intra-articular vertebral body

Question 32

what is the commonest side of TB bone and joints?

Answer 32

vertebral body

Question 33

what are the clinical features of joint and bone TB?

Answer 33

``` insidious onset and general ill health pain, swelling, loss of weight low grade pyrexia joint swelling decreased range of movement ankylosis deformity contact with TB ```

Question 34

what is the presentation of spinal TB?

Answer 34

present with little pain | present with abscess or kyphosis

Question 35

what are the diagnostic features of bone and joint TB?

Answer 35

involvement of single joint marked thickening of synovium marked muscle wasting periarticular osteoporosis around the joint

Question 36

what investigations are carried out to diagnose joint and bone TB?

Answer 36

``` FBC, SR mantoux test sputum/urine culture aspiration xray ```

Question 37

what is the treatment for joint and bone TB?

Answer 37

chemotherapy: rifampicin, isoniazid, ethambutol (8 weeks) then rifampicin and isoniazid (6-12 months) rest and spintage operative drainage