Bone and Joint Infections

Question 1

Q: List 3 mechanisms of OM and give an example of who is at risk for each.

Answer 1

1. Hematogenous spread – pediatric patients
2. Contiguous infection – device implantation/prosthesis
   Direct inoculation – open fracture

Question 2

Q: What is the duration of acute OM? Chronic OM?

Answer 2

o Acute 6wks

Question 3

Q: List the most likely organism causing infection.

Answer 3

o Osteomyelitis in all comers: S. aureus
o Neonates: GBS
o SA in teenagers and young adults: Gonococcal
o Elderly: higher proportion of gram negative bacteria
o Open fractures in fresh water: Aeromonas hydrophilaea
o Dog and cat bites: Pasturella Mutocida
o Human bite: Oral anaerobes, eikinella, streptococcus
o Chronic osteo: Polymicrobial (almost always)
o IVDU: Pseudomonas, staph aures, ecoli
o Sickle cell: Salmonella
o HIV: Staph, candida, Bartonella

Question 4

Q: list the 3 main settings when pseudomonas is responsible for bone and joint infection.

Answer 4

1. Puncture wounds to the foot
   o Colonizes footwear
   
   2. Prosthetic devices implanted in orthopaedic surgery
   3. IV drug users

Question 5

Q: What is an involucrum? Which patient population does it typically occur in?

Answer 5

o periosteal formation/reaction in response to bone infection
o more common in kids

Question 6

Q: What is a sequestrum? Complication associate with this?

Answer 6

o ischemic segments of bone that become separated from surrounding bone;
o can result in pathologic fractures through sequestrum

Question 7

Describe s/s and features of esteomyelitis in children

Answer 7

o Acute
o Hematogenous
o Involves long bones
o Distal metaphysis
o 2:1 male preponderance
fever/chilld/vomiting/limited use

Question 8

What are risk factors for vertenral osteomyelitis

Answer 8

o IVDA
o Bacteremia from indwelling catheters
Sickle cell disease

Question 9

Q: list 3 complications of vertebral osteomyelitis.

Answer 9

o Retropharyngeal abscess
o Psoas Abscess
Epidural Abscess

Question 10

Q: List the complications of OM.

Answer 10

o Chronic osteomyelitis
	o Septic arthritis
	o Brain abscess
	o Meningitis
	o SC compression
	o Pneumonia
	o Growth problems in kids
	o Sepsis complications
	o Staph toxic shock syndrome
Septic Arthritis

Question 11

Q: What is the most likely organism causing SA in neonates and children?

Answer 11

o Neonate: GBS, S. Aureus, Gram-negative enteric bacilli
Consider Candida albicans in prems

3 months – 5 years: S. Aureus

Question 12

Q: What is the classic triad of Disseminated Gonococcal Infection?

Answer 12

1. Migratory Polyarthritis
   o 25% monoarticular
   o Asymmetric
   o Knee, elbow, wrist, MCP, ankle
2. Tenosynovitis
   o Occurs in 2/3
   o Involves hands and fingers
   o Typically asymmetric
3. Dermatitis
   - Occurs in 2/3
   o Variable rash
   o Typical: scattered painless muclopapular lesions with necrotic center

Question 13

What is the role of IV dexamethasone in SA?

Answer 13

o In paediatric hematogenous SA
o IV dexamethasone x 4d
o More rapid recovery
o Markedly reduced joint dysfunction