The Acute Limping Child Flashcards
What is a limp?
An abnormal gait commonly due to pain, weakness or deformity
Pain most common cause
Shorter stance phase and longer swing phase
What are the common sites of origin of a limp?
Most common is hip, knee, leg then foot
Can also originate in back
Why is it difficult to diagnose infection in babies?
They do not have an established immune system and so will not develop a pyrexia
How does limp present in babies?
Pseudoparalysis- will not move affected limb
What initial investigations can be helpful in acute limp?
White cell count CRP ESR Creatinine kinase Blood cultures Checking temperature X-ray Ultrasound
How does septic arthritis present in the lower limb?
- Limping/pseudoparalysis
- Swollen, red joint if joint is superficial
- Refusal to move joint
- Pain temperature
What joints of the lower limb are most commonly affected by septic arthritis?
Knee > hip > ankle
What are the possible routes of infection in septic arthritis?
- Haematogenous spread
- Dissemination from osteomyelitis
- Spread from adjacent soft tissue infection
- Penetrating damage by puncture of trauma
What investigations are helpful in septic arthritis?
- FBC and differential
- ESR
- CRP
- Blood cultures
- X-ray (changes on x-ray in infection will take 2/3 weeks to appear)
- Ultrasound
- Synovial fluid aspiration
What is the most common causative organism of septic arthritis?
Staphylococcal aureus
How is septic arthritis treated?
Affected joint needs drained, which can be done with aspiration, arthroscopy or arthrotomy with a course of antibiotics (usually two weeks IV followed by four weeks oral)
What are the risk factors for osteomyelitis?
Blunt trauma
Recent infection
More common in lower limb than upper limb
Why does osteomyelitis usually limit itself to joints?
Vascular anatomy (vascular loops and terminal branches) Cellular anatomy(inhibited phagocytosis) Trauma
How does osteomyelitis present?
Pain Localised signs Fever Reduced range of movement Reduced weight bearing
What blood tests can be helpful in osteomyelitis?
ESR
CRP
WCC only raised in around 1/3 of affected individuals
