Osteomyelitis

Question 1

Osteomyelitis?

Answer 1

describes an infection of the bone.

Question 2

most common causative bacteria?

except in patients with sickle-cell anaemia?

Answer 2

staph aureus

in patients with sickle-cell anaemia where Salmonella species predominate

Question 3

What is the imaging modality of choice?

Answer 3

MRI with a sensitivity of 90-100%

Question 4

Management?

if penicillin allergic?

Answer 4

flucloxacillin for 6 weeks

clindamycin

Question 5

Predisposing conditions?

Answer 5

diabetes mellitus
sickle cell anaemia
intravenous drug user

Question 6

A 65-year-old man with a history of type 2 diabetes mellitus and peripheral arterial disease is investigated for fatigue and pyrexia of unknown origin. He recently had an amputation of a toe on his left foot. A diagnosis of osteomyelitis is suspected in the left foot. What is the most appropriate investigation?

MRI 
Plain Xray 
PET scan 
Bone biopsy 
CT scan

Answer 6

MRI

Osteomyelitis: MRI is the imaging modality of choice

Question 7

A 6 year-old boy from Sierra Leone presents with a 1 week history of painful left arm. He is homozygous for sickle cell disease. On examination the child is pyrexial at 40.2ºC and there is bony tenderness over the left humeral shaft. Investigations are:

Hb 7.1 g/dL
Blood culture Gram negative rods

X-ray left humerus: Osteomyelitis - destruction of bony cortex with periosteal reaction.

What is the most likely responsible pathogen?

E coli 
Non typhi salmonella 
Pseudomonas aeruginosa
Staph aureus 
Parvovirus B19

Answer 7

Non typhi salmonella

Blood and bone infections caused by non-typhi salmonella (NTS) are typically associated with malaria and homozygous sickle cell disease, especially in children.

Question 8

A 6-year-old boy with sickle cell disease presents to the emergency department. He has been febrile for one week now and feels nauseous with a lack of appetite. Within the last day, he has been experiencing severe pain in his left leg. You initially treat this as a sickle crisis giving adequate oxygen, fluids, morphine and antibiotics. However, an X-ray was done which showed osteomyelitis of the leg.

Which of the following organisms is the likely cause of his osteomyelitis?

Neisseria gonorrhoea
Haem influenzae
Group A streptococci
Salmonella enteritidis

Answer 8

Salmonella enteritidis

Question 9

A 30-year-old intravenous drug user is diagnosed as having osteomyelitis of the right tibia. What is the most likely causative organism?

salmonella species
Haem influenzae
Staph aureus
Enterobacter species

Answer 9

Staph aureus