Osteomyelitis (+infection basics) Flashcards
What antibiotic is 1st line against staphylococcus aureus?
Flucloxicillin
What antibiotic is 1st line against staphylococcus epidermidis?
Vancomycin
What antibiotic is 1st line against streptococcus pyogenes?
Doxycycline
What antibiotic is first line against gram -ve bacteria?
Clindamycin (4C)
What antibiotic is 1st line against anaerobes?
Metronidazole
What antibiotics are used in cases of MRSA?
Vancomycin
Teicoplanin
Daptomycin
What is osteomyelitis?
An infection of the bone
What are some methods of contracting acute osteomyelitis?
Trauma (Open fracture)
Haematogenous spread
What are some risk factors for developing osteomyelitis?
Diabetes
PWID
Young age
Immunosuppressed
What are the most common causative bugs in osteomyelitis?
- Staphylococcus aureus (1st)
- Group A Streptococcus (2nd)
- Haemophilus (Children)
In what cases should gram -ve osteomyelitis be suspected?
If there is also a UTI
What is the cause of chronic osteomyelitis?
Untreated acute osteomyelitis
How does chronic osteomyelitis occur?
Untreated osteomyelitis goes on to affect the metaphysis, causing bone death, abscess formation and spread to the space beneath the periosteum
This causes formation of an involucrum (New layer of bone outside of the pus
What is an involucrum?
A new layer of bone that forms outside of the pus-filled layer beneath the periosteum
How will osteomyelitis usually present?
Localised pain
Slight fever
What are some other infections that may occur in osteomyelitis?
Skin infections such as necrotising fasciitis
What tests are required in diagnosis of osteomyelitis?
Probe to bone test (Culturing)
Blood testing
How will staphylococcus test under culturing?
Gram positive
Cocci
Coagulase positive
Gold on blood agar
What are some toxins that staphylococcus aureus can produce?
- Enterotoxin - Food poisoning
- SSSST - Staphylococcal Scalded Skin Syndrome Toxin
- PVL - Panton Valentine Leukocidin
Why can antibiotics alone not be used in osteomyelitis?
Open fractures are often poly-microbial and have very little vascularisation, meaning that antibiotics alone cannot control all organisms or reach some centre of bone
There can also be pus in the bone, which antibiotics cannot clear
What treatments are required in osteomyelitis?
Antibiotics to culture
Debridement
Pus release
What antibiotics are used in staphylococcus aureus in osteomyelitis?
IV flucloxacillin is given first, followed by oral doxycycline
What is the treatment used in vertebral osteomyelitis?
drainage of para-vertebral or epidural abscesses, with 6 weeks minimum antibiotics given
