Septic arthritis Flashcards
Define septic arthrits.
Septic arthritis is defined as the infection of 1 or more joints. It occurs either by direct inoculation or via haematogenous spread.
What are the risk factors for septic arthritis?
- Joint disease underlying
- OA, Rha
- Prosthetic joint
- Age - especially >80yo
- Immunosuppression
- HIV
- IV drug use
- Diabetes
- Alcohol misuse
- Immunosuppressive meds
- Contiguous spread e.g. from cutaneous ulcers or skin infection
- Haematogenous spread
- Iatrogenic
- Intraarticular corticosteroid injection
- Exposure to ticks
What are the clinical features of septic arthritis?
- Hot, swollen, painful, restricted joint - reluctant to be examined, unable to weight bear
- Severe limitation of active and passive movement
- Acute presentation - symptoms usually present for <2 weeks
- Fever
- Single, large joint affected
- Prosthetic joint
What investigations would you do to diagnose septic arthritis?
-
Joint aspiration for:
- Microscopy, gram stain and polarising microscopy
- Culture and sensitivities
- WCC
- +/- PCR
- Blood culture
- +/- Swabs
- FBC - WCC
- ESR and CRP
-
U&Es
- Although urate would not differentiate between gout and infection
- LFTs - assess for end organ damage in the case of sepsis
- Urine dip, MC&S
-
Plain XR
- Baseline of joints
- Not urgent
What are some differentials for septic arthritis?
- Gout/pseudogout (main differential)
- Haemarthrosis
- Trauma
- Bursitis
- Cellulitis
- RhA
- PsA
- OA
What is the management of septic arthritis?
- Sepsis protocol if there are systemic symptoms + senior help (ST4 or above)
- IV antibiotics (contact microbiology) - once joint and blood cultures have been taken. Continue for up to 2 weeks IV then start oral for 4 weeks.
- Repeat joint aspiration to dryness as often as necessary +/- washout (if no improvement in CRP)
- Analgesia
- Refer to orthopaedics if prosthetic joint or inaccessible joint such as the hip.
- Refer to ICU if systemic sepsis with end organ involvement
What are the most common organisms causing septic arthritis?
- Staph aureus
- Streptococci
- N. gonorrhoea
Staphylococci or streptococci account for 91% of cases
Which antibiotic is usually used to treat septic arthritis?
Staphylococcal/streptococcal is treated with IV flucloxacillin
If gram -ve suspected then consider cephalosporin.
What kind of monitoring is done for septic arthritis?
- WCC
- ESR, CRP
- Procalcitonin
- Renal and hepatic function
Every 24-48hrs depending on local protocol. Usually takes about 48hrs for the antibiotics to work.
What are the complications of septic arthritis?
Joint destruction
Osteomyelitis
