child with a limp Flashcards
what is acute haematogenous osteomyelitis
haematogenous spread of pathogens seeding into the bone
usually staph aureus
what is septic arthritis
intra-articular infection of a synovial joint
may coexist with osteomyelitis
what are the common causes of septic arthritis
staph aureus is the most common cause
GBS in neonates and Kingella Kingae in toddlers
Haemophilus influenzae in unimmunised
consider underlying illness and unimmunised (salmonella)
discitis
inflammation/infection of an intervertebral disc, typically occuring in pre-school aged children and most often affecting the lumbar spine
site of pain
most commonly hip or knee but could be any synovial joint
osteomyelitis: most commonly femur or tibia, pelvis and humerus but any long bone
fever
may be absent in osteomyelitis
usually present in septic arthritis or pyogenic myositis
typically absent in discitis or transient synovitis or low grade
onset of pain
osteomyelitis: subacute onset of limp, non-weight bearing or refusal to use limb
septic arthritis: acute onset of limp, non-weight bearing or refusal to use limb
pyogenic myositis: subacute onset, may involve limp
discitis: subacute onset of irritability and back pain. may involve limp or refusal to crawl or walk
transient synovitis: subacute or acute onset of limp, recent recovery from viral illness
pain in osteomyelitis
poorly localised
septic arthritis pain
hot, swollen, painful, immobile joint
pyogenic myositis type pain
pain usually well localised
may have abdominal pain (psoas involvement)
discitis type pain
refusal to bed forward, loss of lumbar lordosis, percussion tenderness over spine, hip pain, lower limb neurology, ileus
transient synovitis type pain
weight bearing with limp
systemic features
osteomyelitis: with or without systemic illness
septic arthritis: usually more severe systemic symptoms
pyogenic myositis: systemic symptoms usually more severe
discitis: irritable, with or without systemic illness
transient synovitis: systemically well, recent viral symptoms
examination
look: resting limb position (hip flexed, abducted and externally rotated), swelling and erythema, open wounds or soft tissue infection
feel: tenderness, warmth, effusion
move: passively in all places of motion and actively
DDx
transient synovitis
trauma including NAI
inflammatory conditions eg. inflammatory arthropathy, chronic recurrent multifocal osteomyelitis, acute rheumatic fever
pyogenic myositis
discitis
malignancy, including leukaemia
DDH in toddlers and children
perthes disease
SUFE
investigations
not necessary if child is systemically well, afebrile and weight bearing without significant discomfort, working diagnosis and early follow up is sufficient
FBC, CRP, ESR, blood culture
x-ray
joint US
when should blood cultures be taken
prior to antibiotics if possible
FBC, ESR and CRP
may be normal
blood film if concern for malignancy
especially in early or chronic infection, or of infection of the small bones
synovial fluid aspiration
where appropriate, in cases of suspected septic arthritis
should not delay antibiotic treatment
x-ray
used to exlcude fracture and malignancy
usually normal up to 7-10 days in osteomyelitis
ultrasound
to identify joint effusion in suspected septic arthritis
highly sensitive but not specific
MRI with contrast
preferred test for osteomyelitis especially where symptoms are localised
may demonstrate sub periosteal abscess or marrow involvement
highly sensitive for myositis
use if still limping after 7 days
technetium bone scan
may be useful where access to MRI is limited
a positive bone scan is not a specific finding
negative bone scan cannot rule out infection or other serious pathology
treatment for septic arthritis
urgent aspiration +/- arthrotomy and washout
do not delay antibiotics
antibiotic treatment
for uncomplicated cases of osteomyeltisi and septic arthritis commence
flucloxacillin IV every 6 hours
for children under 4 year commence
Cefazolin IV every 8 hours
consider discharge when
child tolerating oral antibiotics or has planned outpatient IV therapy eg. hospital in the home
afebrile, well child
improved inflammatory markers and clinical indicators
weight bearing/using involved limb
safety netted
red flags on history
> 7 days duration
severe localised pain
change to urinary or bowel habit
complete inability to walk or weight bear
nocturnal pain
systemic symptoms
consitutional symptoms
red flags on examination
generalised wasting
fever
petechiae/purpura/ecchymosis
pelvis AP or frog leg view x-ray
useful for identifying SUFE, DDH > 6 months, perthes disease and common pelvic avulsions
child with a limp flowchart
Kocher criteria
in a child with hip pain the presence of the following 4 crietria increases the liklihood of septic arthritis
- fever >38.5
- non-weight bearing
- leucocytosis >12
- ESR >40 or CRP >20
you should refer if 2 or above, 3 or above is very high probability of septic arthritis
