Septic arthritis Flashcards
Define septic arthritis
Joint inflammation resulting from intra-articular infection
AKA infective arthritis
Aetiology of septic arthritis
2
May be idiopathic
In most cases there’s systemic infection allowing for haematogenous spread
Risk factors for septic arthritis
5
Recent orthopaedic procedures Osteomyelitis Diabetes Immunosuppression Alcoholism
Causative organisms for septic arthritis
7 bacteria, 4 virus, fungi
Bacteria All ages Staphylococcus aureus TB <4 yrs Streptococcus pneumoniae Streptococcus pyogenes Neisseria meningitidis Gram negative rods 16-40 yrs Neisseria gonorrhoeae
Viruses Rubella Mumps Hepatitis B Parvovirus B19
Fungi
Candida
Epidemiology of septic arthritis
ages
Most common in CHILDREN & ELDERLY
Presenting symptoms of septic arthritis
5
Fever
Excruciating joint pain
Joint redness, swelling & loss of joint function
Usually monoarthropathy (1 large joint) but poly in immunocompromised
Tuberculous arthritis develops more slowly & is chronic
Signs of septic arthritis on physical examination
6
Painful, hot, swollen Immobile joint Erythema Severe pain prevents passive movement Pyrexia Look for signs of aetiology
Investigations for septic arthritis
4 types
Joint aspiration
Bloods
Plain joint radiographs
MRI scan
Investigations for septic arthritis - joint aspiration
3
(IMPORTANT)
Aspirate will be grossly purulent
Send synovial fluid for MC&S (microscopy to rule out crystals)
PCR may be used if viral cause suspected
Investigations for septic arthritis - bloods
4
FBC - high WCC & neutrophils
High CRP & ESR
Blood cultures - MC&S
Viral serology may be useful
Investigations for septic arthritis - plain joint radiograph
2
Affected joint may look normal initially
Can show signs of damage following infection
Investigations for septic arthritis - MRI
Useful for detecting osteomyelitis
