Osteomyelitis Flashcards
What is osteomyelitis?
inflammation of bone and medullary cavity, usually located in one of the long bones
What is the treatment for osteomyeltisi?
debridement and antimicrobials
what type of infection is an open fracture?
contiguous infection
What are the symptoms of infection of an open fracture?
non-union and poor wound healing
What organisms are implicated in open frcature infections?
staph. aureus; aerobic gram negatve bacteria
What causes osteomyelitis with diabetic/venous ulceration?
contiginous infection
How is the depth of the infection in an infected ulcer?
probe to the bone
What is the rule of 2?
if the ulcer has been there for 2 months and >2 months then check for osteomyelitis and if can see tendon or bone
What are the indications for an x-ray with an ulcer?
if the ulcer is:
- chronic, indolent or deep
- there is a +ve probe-to-bone test
- increased levels of inflam markers
What is required to diagnose definitive osteo?
bone biospy for histology and culture
What should be avoided with antibiotic therapy in osteomyelitis?
empirical therapy- a biospy should always be done
When should empirical therapy be give?
if have sepsis or skin and soft tissue involvement
What empirical therapy would be given?
flucloxacillin
Who is haematogenous osteomyelitis seen in?
prepubertal children; PWID; central lines/ dialysis/ eldery
What bug is the infecting microbe if someone steps on a nail typically?
pseudomonas
What are the main organisms seen with PWIDs?
staph; strep
What are the main pathogens seen in dialysis patients?
staph aureus; aerbic gram negatives
What should you do if a patient with an IV has a positivie blood culture?
remove the IV line and repeat cultures until negative
What should be done if a patient has persistent positive blood cultures?
an echo
What predisposes to osteitis pubis?
urogynae procedures
What are the risk factors for clavicle osteo?
neck surgery and subclavian vein catheterisation
What pathogens are seen with sickle cell osteo?
salmonella and staph. aureus
Where is is sickle cell osteo seen in the body?
long bones
What is gauchers disease?
lysosomal storage disorder
What is SAPHO?
synovitis acne pustulosis hyperostosis osteitis
What is CRMO?
chronic recurrent multifocal osteomyelitis
What is the difference between SAPHO and CRMO?
SAPHO is seen in adults whereas CRMO is seen with children
What are SAPHO and CRMO?
osteomyeltiis like lesions-mulitfocal osteitis which is self-limited
How is osteo myeltiis excluded in SAPHO and CRMO?
history plus cultures
What is seen on investigations with SAPHO and CRMO?
raised inflam markers and lytic lesions on x-ray
What is the presentation of SAPHO and CRMO?
fever, weight loss, maliase, 5 or so active lesions in strange places- chest wall, pelvis
What might vertebral osteomyelitis be associated with?
epidural or psoas abscess; PWID; IV site infections; GU infections:SSTI; post-op
What are the features of vertebral osteomyelitis?
fever; insidious pain and tenderness; neurogloical signs; raised inflam markers; raised WBCs
What is the treatment for vertebral osteo?
draingae of large paravertebral/epidural abscesses; antimicrobials for 6 weeks
Why would an MRI be repeated in vertebral ostea?
unexplained increase in inflam marker; increasing pain; new anatomically related signs/symptoms
What is vertebral TB also known as?
Pott’s disease
What is seen in patients with vertebral TB?
often NO systemic symptoms; half have skin and soft tissue infections and less than half have pulmonary TB
What should always be offered for in adults with skeletal TB?
HIV test
What should be checked in kids with vertebral TB?
reduced receptors for IFN-gamma; R1 etc
What are the risk factors for a prosthetic joint infection?
RA; diabetes; malnutrition; obesity
What are the mechanisms for infection of a prosthetic joint?
direct inoculation at time of surgery
manipulation of joint at time of surgery
seedingb of joint at a later time
What causes an early infection in prosthetic joints?
wound sepsis/haematoma- within one month
What causes a late infection in prosthetic joints?
contamination at the time of operation
Whhat local infections does S. aureus cause?
impetigo; funuculosis; cavitating pneumonia; osteomyelitis; septic arthritis
What systemic infections does staph. aureus cause?
bacteraemia; metastatic abscess; endocarditis; line-related sepsis
What toxin mediated diseases can staph. aureus cause?
acute gastroenteritis; toxic shock syndrome; scalded skin syndrom
What is PVL?
a toxin called panton-valentine-leukocidin that kills WBCs
What are the symtpoms of having a PVL producing Staph, aureus
skin infections; necrotising pneumonia; invasive infections eg bacteraemia, septic arthritis
What is a planktonic bacteria?
one that causes bacteraemia
What is sessile bacteria?
when planktonic bacteria undergo phenotypic transformation and form a biofilm with an ECM
How is infection of prosthetic joints diagnosed?
from mltiple cultures of perioperative tissue
What is the treatment for an infection of prosthetci joints?
removal of prosthesis and cement and antibiotic therapy fro at least 6 weeks and then re-implantation of the joint
What are the main pathogens that can cause infections of prosthetics?
staph. aureus, staph, epidermidis mainly
What is the significanve of prosthetic material with coagulase negative staph (staph. epi)
they have a low virulence and can only cause infection if prosthetic material is presnet
What is needed to treat PVL infection?
fluclox and an anti-toxin antibiotic- clindamycin or linezolid
what is the side effecto f clindamycin?
C. diff infections
What is the sie effevt of linexolid?
bone marrow failure
What antibiotic is used t/o treat cog negative staph?
vancomycin
What is the virulence factor in staph. epi?
slime which allows it to bind to plastic and form biofilms
How can septic arthritis occur?
haematogenous spread; direct invasion through a penetrating wound; spread from infectious focus (cellulitis, abscess) in adjacent soft tissues; spread from focus of osteomyelitis in adjacent bone
What is septic arthritis?
inflammation of the joint space caused by infection
What organisms cause septic arthritis?
staph. aureus; strep; coag neg staph. - prosthetic joints; neisseria gonorrhae- sexually active; haemophilus0 pre-school
What is the clinical presentation of septic arthritis?
sever pain, red, hot swollen plus limited movement, fever (if haematogenous)
What are the empirical antibiotics given for septci arthritis?
fluclox; ceftriaxone- in under 5s
What viruses can cause viral arthritis?
hep B; rubella; parvovirus; alphavirus
what is pyomyositis?
pussy muscle
What causes pyomyositis?
90% are staphylococcal but it depends on the site
How is pyomyositis treated?
wide debridement- removal of the infected muscles
What causes tetanus?
clostridium tetani
What is clostridium tetani?
gram positive strictly anaerobic rods- drumstick shapes
Where are tetenus spores found?
soil; gardens etc
How does tetanus cause illness?
the organism itself isnt invasive, illness is caused by a neurotoxin
What does tetanus do?
causes spastic paralyiss by binding to inhibitory neurones, preventing release of neurotransmitters
What is the incubation period for tetanus?
4 days to several weeks
what causes lock jaw with tetanus?
muscles spasming
What kills you with tetanus?
go into resp arrest as resp msucles are in spasm
What is the treatment for tetanus?
surgical debridement; antitoxin; supportive measures; antibtiocs; booster vaccination- toxoid
What is myositis?
viruses; protozoa; fungal infections
What is a myositis caused by protozoa associated with?
eosinophilia
What happens to the bone in osteomyelitis?
exudation of pus lifts up the periosetum interrupting blood supply to underlying bone and necrotic fragments of bone may form (sequestration. New bone formation created by the elevated periosteum forms an involcrum. Pus may dischanrge into joint spaces or via sinuses to the skin
What are the radiographic changes associated with osteomyelitis?
haziness+/- loss of density of afffectedf bone, then subperiostal reaction, and later, sequestrum and involcrum
What has reduced the prevalence of haemophilus influenzae osteo in children?
vaccine
what are sequestra?
infected dead bone
What are the signs of bone TB?
local pain, swelling, cold abscess formation +/- joint effusion; pain on movement and muscle wasting- if includes joint; wt lossl malaise; fever; lethargy
Who typically gets osteo in their feet?
diabetics
Who typically gets osteo in their vertebra?
IVDU
What types of bone tends to get infected in children?
vascular bone - long bone metaphyses
What are the signs of infection?
rubor; calor; dolor; tumour; functio laesa
What is important in the treatment of bone and joint infection?
dont start antibiotics until you know what youre treating
What does the technetium scan show?
osteoblast activity
What is the most common cause of acute osteomyelitis?
post-trauma/ open fractures
What causes acute osteomyelitis in children and immunosuppresssed?
haematogenous spread
What is the most common organism in acute osteomyelitis?
staph. aureus
What bug causes acute osteomyelitis in children?
haemophilus influenzae
What causes haematogenous osteomyelitis?
there is a clot in the blood vessel of the bone- which acts like an agar plate fro bacteria. blood flow in bone is already slow, if there is trauma this can damage the vessel wall- virchows triad
What imaging is used in diagnosing chronic osteomyelitis?
x-rays and MRI
What bugs should be covered in cellulitis?
staph and strep- fluclox and benzylpenicillin
What can be felt on palpation with necrotising fasciitis?
bubble wrap- organisms produce gas
What suggests an infected arthroplasty in the history?
if there has been poor wound healing and if the joint has always been painful
How are prosthetic infectiosn prevented during surgery?
clean air theatre; local antibiotics; systemic antibiotics; and a reduced duration of surgery
Which bugs infect prosthetics?
staph aureus and staph. epi (coag neg staph CNS)
