infective arthiritis Flashcards
what are the 2 types of infective arthritis?
septic arthritis
osteomyelitis
define infective arthritis
The infection of the bone (osteomyelitis) or synovial joint space (septic arthritis).
what causes septic arthritis
it is the direct infection of the synovial joint space by bacteria, viruses, or fungus.
how does a septic arthritis infection spread
- spread from adjacent soft tissues/joints
or - hematogenous infection that has travelled through the blood to the infection site
or - the result of direct infection due to trauma/surgery.
most common causative organisms for septic arthiritis
- Staphylococcus aureus (esp. MRSA)
- Streptococci
- STI organisms (Neisseria gonorrhoeae)
- H influenza (children)
- E coli
most common age range of people affected by septic arthiritis
Most common in children under 4 years or older adults.
risk factors for septic arthritis
- Pre-existing joint disease (OA or RA)
- Joint prostheses
- IVDU
- Immunosuppression
- Alcohol misuse
- Diabetes
- Intra-articular corticosteroid injection
signs and symptoms of septic arthirits
- Intense joint pain
- Swelling
- Redness
- Warmth of joint
- Reduced range of motion
- systemic symptoms (fever, lethargy, sepsis)
most common affected area of septic arthritis
knee or hip, usually only affects one knee
duration for onset of symptoms
less than 2 weeks
differential diagnosis for septic arthiritis
- Transient sinovitis
- perthes disease
- slipped upper femoral epiphysis
- juvenile idiopathic arthritis
investigations for septic arthiritis
- joint aspiration
- blood culture
- sexual health review
- X ray/MRI/ultrasound
- synovial fluid analysis
what does joint aspirate do
gram staining, crystal microscopy, MC+S.
Gram staining will come back quite quickly and can begin to guide treatment.
what would a blood culture of septic arthritis find
raised WCC
raised ESR+CRP
treatment of septic arthiritis
- Aspirate joint, Surgical drainage and washout of the joint to clear the infection in severe
- Empirical Abx e.g. flucloxacillin
- Pathogen-directed Abx (only after results from aspirate come back) continued for 3 to 6 weeks
- Analgesia - NSAIDS
what can you not give septic arthritis patients
methotrexate
what to do if a septic arthritis patient is on steroids
double the prednisolone dose
define osteomyelitis
Inflammatory condition of bone caused by infecting organism
what are chronic infections of osteomyelitis the result of
Chronic infections are likely a result of multiple different microbes,
what are acute infections of osteomyelitis the result of
acute infections are likely a result of a single organism.
most common causative organism of osteomyelitis
staph aureus
how is osteomyelitis spread
- local -due to direct contamination of the bone
or
- haematogenous - when a pathogen is carried through the blood and seeded in the bone
does osteomyelitis affect children or adults more
children
risk factors for osteomyelitis
- Open fractures
- Orthopaedic operations, particularly with prosthetic joints (1% of replacements)
- Diabetes, particularly with diabetic foot ulcers
- Peripheral arterial disease
- IV drug use
- Immunosuppression
- Children → upper resp tract or varicella infection
- sickle cell anaemia
signs and symptoms of acute osteomyleitits
- fever
- dull, bony Pain
- Swelling
- Erythema.
signs and symptoms of chronic osteomyelitis
- persistent pain
- Soft tissue damage
- Continuous draining sinus tract/wound.
investigations for osteomyelitits
- Bone marrow biopsy – DIAGNOSTIC
- Blood inflammatory markers (ESR + CRP)
- X-ray/MRI/CT
- Blood cultures
treatment of osteomyelitis
Antibiotics (min. of 4 weeks, to upwards of 6 months) - flucloxacillin
Surgical debridement (surgical cleaning)
differential diagnosis for osteomyelitis
charcot joint - damage to sensory nerves due to diabetic neuropathy
