Bone infections Flashcards
in what age group and sex is acute osteomyelitis more common in?
children
boys > girls
what puts a patient at risk of acute osteomyelitis?
immunocompromised diabetes mellitus sickle cell disease long term steroid treatment rheumatoid arthritis
what are the 3 main sources of infection of acute osteomyelitis?
haematogenous spread from blood born infection
local spread from a contiguous infection
secondary to vascular insufficiency (necrotic distal limb = penetration of skin = organisms enter)
what are the main causes of blood born infections which can cause acute osteomyelitis?
(infants, children & adult)
infants - infected umbilical cord
children - boils, sinusitis, skin abrasions
adults - UTI, arterial line
what is the most common causative organism of acute osteomyelitis?
staph aureus
what is the most common causative organism for acute osteomyelitis in drug abusers ?
pseudomonas aeroginosa (also penetrating foot injuries)
what is the most common causative organism for acute osteomyelitis if the patient has sickle cell disease?
salmonella sp.
at what part of the bone does osteomyelitis start?
metaphysis
what are the medical terms for bone necrosis and bone formation?
necrosis = sequestrum formation = involucrum
what are the signs of osteomyelitis in infants?
failure to thrive decreased range of movement positional change possibly drowsy, irritable metaphysical tenderness + swelling
where is the commonest site of acute osteomyelitis in an infant?
around the knee
often occurs in multiple sites in infants
whats the presentation of acute osteomyelitis in a child?
severe pain reluctant to move, not weight bearing, neighbouring joints held flexed tender swinging pyrexia tachycardia malaise (nausea, vomiting, fatigue)
what is the most common primary site of acute osteomyelitis in adults?
thoracolumbar spine
what is the most common causative organism of primary acute osteomyelitis in an adult?
staph aureus
what investigations would you carry out to diagnose acute osteomyelitis?
history and examination FBC & WCC ESR, CRP blood cultures (x3) , bone biopsy U&E xray USS aspiration isotope bone scan labelled white cell scan MRI
what is the treatment duration of acute osteomyelitis?
4-6 weeks depending on the response and ESR
what is the treatment for acute osteomyelitis?
supportive i.e. analgesia
rest and splintage
antibiotics i.e. flucloxacillin and benzylpenicillin (empirical awaiting microbiology)
surgery
what are the complications of acute osteomyelitis?
septic arthritis pathological fractures septicaemia, death altered bone growth chronic osteomyelitis metastatic infection
what are the causes of chronic osteomyelitis?
follow acute osteomyelitis
following operation, open fracture
immunosuppressed
repeated breakdown of healed wounds
what is the causative organism(s) of chronic osteomyelitis?
staph aureus, e.coli, staph progenies, proteus
what are the complications from chronic osteomyelitis?
chronically discharging sinuses + flare ups
ongoing metastatic infection (abscesses)
pathological fracture
growth disturbance + deformities
squamous cell carcinoma
what are the different treatment options for chronic osteomyelitis?
long term antibiotics - local i.e. gentamicin cements, collatamp - systemic i.e. oral, IV surgery (multiple) treat soft tissue infections correct deformity amputation
what are the routes of infection for acute septic arthritis?
haematogenous eruption of abscess penetration - penetrating wound - intra-articular injury - arthroscopy
what are the common causative organisms of septic arthritis?
staph aureus
haemophillus influenzae
strep pyogenes
e.coli
what is the pathology in acute septic arthritis?
acute synovitis with purulent effusion
articular cartilage is attacked by bacterial toxin and cellular enzyme
complete destruction of the articular cartilage
what is the sequelae of septic arthritis?
complete recovery
partial loss of the articular cartilage and subsequent OA
fibrous or bony ankylosis
what is the presentation of septic arthritis in children/adults?
acute pain in a single large joint
- reluctant to move the joint in any movement
- increased temp and pulse
- increased tenderness
what is the commonest cause of septic arthritis in an adult?
infected joint replacement
what is the most common causative organism that causes septic arthritis from infected joint replacement ?
staph epidermidisis
what is the treatment for acute septic arthritis?
supportive measures
antibiotics (if pus then surgical)
surgical drainage and lavage
1 or 2 stage revision of infected joint replacement
what are the classifications of TB in bone and joints?
extra-articular
intra-articular
vertebral body
what is the commonest side of TB bone and joints?
vertebral body
what are the clinical features of joint and bone TB?
insidious onset and general ill health pain, swelling, loss of weight low grade pyrexia joint swelling decreased range of movement ankylosis deformity contact with TB
what is the presentation of spinal TB?
present with little pain
present with abscess or kyphosis
what are the diagnostic features of bone and joint TB?
involvement of single joint
marked thickening of synovium
marked muscle wasting
periarticular osteoporosis around the joint
what investigations are carried out to diagnose joint and bone TB?
FBC, SR mantoux test sputum/urine culture aspiration xray
what is the treatment for joint and bone TB?
chemotherapy: rifampicin, isoniazid, ethambutol (8 weeks) then rifampicin and isoniazid (6-12 months)
rest and spintage
operative drainage
