Septic arthritis Flashcards
Define septic arthritis
Infectious arthritis -> potentially life threatening -< direct infection of the synovial joint space.
Commonly bacterial -> can be fungal or viral.
What is the epidemiology of septic arthiritis?
In children - more common in preschool infants and toddlers
Most commonly affects the hip and knee joints.
What are the most common pathogens causing septic arthritis?
Staphylococcus aureaus (MRSA)
Group A strep
Enterobacter
Haemophilus influenza
Fungi and viruses less common
What are the different ways pathogens can reach the joint in septic arthritis?
Haematogenous spread - children
Contiguous site of infection - osteomyelitis
Direct inoculation - trauma or surgery
What is the concerning underlying pathology in septic arthritis in paediatric cases?
Response from inflammatory cells causes destruction of cartilage
Leads to increased intracapsular pressure -> growth plate damage and avascular necrosis
What is a key risk factor for septic arthritis?
Haemophilius influenza
How do children with septic arthiritis tend to present?
Fever
Refusal to weight bear
Swelling and effusions
Warmth over joint
Reduced range of motion and pain on passive movement
Abnormal join positioning
What investigations should be done for a diagnosis of septic arthritis?
Bedside - synovial fluid aspiration - gram stain, culture, cell sount
Blood - FBC, CRP, ESR, blood cultures
Imaging - US show effusion, X-ray - joint space widening, effusion or bony destruction
MRI - detailed
What is the key management of septic arthritis?
IV initially then 4-6w oral
Flucloxacillin first line
Clindamycin if allergic
Surgical drainage - remove infected fluid
What are the key complications of septic arthritis?
Osteomyelitis - spead of infection to surrounding bones
Joint destruction
Chronic pain
Growth problems
What factors are associated with poor prognosis from a septic arthritis?
Knee, hip or shoulder involvement
Age < 1yr
Delay to treatment
