bone infection and a bit more arthritis Flashcards
Questions focussing on reactive, psoriatic, and septic arthritis (i.e. the arthritic diseases upon which the syllabus places less importance, and which are less common). Also includes information about osteomyelitis.
who is likely to get reactive arthritis?
a 20 year old 1-4 weeks post chlamydia
signs of reactive arthritis
swelling and pain of the knee, ankle, and foot
iritis
mouth ulcers
Reiter’s syndrome
what does Reiter’s syndrome involve?
urethritis
conjunctivitis
arthritis
diagnosis of reactive arthritis
increased ESR and CRP
culture stool if diarrhoea
sexual health review
treatment of reactive arthritis
splint joint
NSAIDs
consider methotrexate or sulfasalazine after 6 months
who will develop psoriatic arthritis?
someone with psoriasis
signs of psoriatic arthritis
dactylitis
pitting
telescoping
nail changes
diagnosis of psoriatic arthritis
erosions visible on XR
resorption of terminal phalanges
treatment for psoriatic arthritis
NSAIDs methotrexate sulfasalazine cyclosporin anti-TNF agents
risk factors for osteomyelitis
damaged joint bacteraemia trauma skin break ulcer diabetes rheumatoid arthritis immune diseases elderly immunosuppression peripheral vascular disease
which organism is likely to cause osteomyelitis in native joints?
S.aureas
how can someone develop osteomyelitis?
3 causes
haematogenous spread
direct inoculation
contigious spread (from adjacent tissues)
how does osteomyelitis look on a plain x-ray?
cortical erosion periosteal reaction mixed lucency sclerosis sequestra soft tissue swelling
signs of osteomyelitis
fever pain fatigue lost range of motion swelling red and warm nausea
what should you do with patients with staphylococcal bacteraemia?
ECHO to rule out infective endocarditis
MRI spine to rule out osteomyelitis
differential diagnosis for osteomyelitis
gout soft tissue infection Charcot joint avascular necrosis malignancy bursitis fracture
diagnostic tests for osteomyelitis
bloods - FBC, U&E, CRP and ESR raised
XR and MRI
PCR
marrow aspiration
how high is CRP for an infection?
> 150
pathology of acute osteomyelitis
inflammatory cells, oedema, vascular congestion, small vessel thrombosis, high WCC
pathology of chronic osteomyelitis
necrotic bone sequestra, new bone formation, neutrophil exudates, lymphocytes, histiocytes
treatment of osteomyelitis
surgery - aspirate and wash out joint antibiotics - initially broad spectrum (ceftriazone) stop immunosuppression if on prednisolone, double the dose analgesia splinting and rest
how long should you treat TB osteomyelitis for?
12 months
which antibiotics should you use to treat S.aureus osteomyelitis?
flucoxacillin, erythromycin, or doxyltetracycline
what percentage of cases of septic arthritis are caused by Staphylococci?
50%
what is the success rate for one stage exchange for the treatment of septic arthritis?
85%
two stage exchange has a 90-95% success rate
risk factors for septic arthritis
prosthetic joint diabetes mellitus immunosuppression elderly damaged joints
what is most likely to cause septic arthritis is young and sexually active patients?
Gonococcal
what is most likely to cause septic arthritis in immunocompromised patients?
Strep pyogenes
P.aeruginosa (IVDU)
TB
signs of septic arthritis
prosthetic loosening expansion of cortex on XR ectopic bone formation painful to move joint high temperature signs of inflammation
diagnosis of septic arthritis
joint aspirate and culture
XR
FBC, ESR, alpha-defensin
how to prevent septic arthritis
totally clean operating theatre
give patients broad spectrum antibiotics and clean skin with antibiotics prior to joint surgery
gentamicin in bone cement
treatment for septic arthritis
aspirate for pain IV antibiotics surgery - joint washout / amputation / exchange arthroplasty RICE physiotherapy temporarily stop immunosuppression
which organisms are likely to cause septic arthritis in children?
S.aureus
group A strep
gram -ve bacilli
