Microbiology Flashcards
Osteomyelitis
Inflammation of bone and medullary cavity, normally in one of the long bones
Contiguous vs haematogenous source
Contagious - coming directly or adjacent to eg. break, surgery or bite
Haematogenous - coming from blood stream
What is the most important pathogen in osteomyelitis?
Staph aureus
What are the main subtypes of osteomyelitis?
1) Open fracture
2) Diabetes/vascular insufficiency
3) Haematogeneous osteomyelitis
4) Vertebral osteomyelitis
5) Prosthetic joint infection
What is the ‘Rule of 2’s in diabetic insufficiency with osteomyelitis?
If the ulcer has been there for more than 2 months and is more than 2 cm in diameter then it is likely there will be osteomyelitis
What is the management for suspected osteomyelitis?
1) Examine, inflammatory markers probe to bone test
2) Radiography
3) Bone biopsy
4) Debridement and antimicrobials
What situations are the exception to waiting for biopsy before giving antibiotics?
Suspected sepsis or severe soft tissue involvement
In what groups of people does haematogenous osteomyelitis occur?
PWID (People who inject drugs) and children (large bone blood supply as still growing)
Which pathogens are most common in PWID osteomyelitis?
Staph and strep
What is the most common source for vertebral osteomyelitis, and what can they be associated with?
Haematogenous, can be associated with psoas abscess or epidural abscess
Pott’s Disease
Skeletal TB when it is in the vertebrae
What are the risk factors for prosthetic joint osteomyelitis?
RA, diabetes, malnutrition and obesity
What is the most important pathogen in prosthetic osetomyeltits, and what is its treatment?
Staph epidermidis - Vancomycin
Septic arthritis
Inflammation of the joint space caused by infection
What is the investigations for septic arthritis?
Joint aspiration > Microscopy, C&S
Blood culture if pyrexial
Exclude crystals
