Acute monoarthropathy
Jaya Ravindran
Rheumatologist
Aims
• an approach to the investigation and
differential diagnosis of acute
monoarticular pain
• focus on septic and crystal arthritis
Acute Monoarthritis - differential
diagnosis
– Septic arthritis
– Crystal arthritis
• Gout (uric acid)
• Pseudogout/calcium pyrophosphate deposition
disease (CPPD)
What are other differentials for
acute monoarticular pain?
Monoarthritis - differential
diagnosis
Psoriatic arthritis
–
–
–
–
Onycholysis
Subungual hyperkeratosis
Pitting
Extensor surfaces, scalp,
natal cleft, umbilicus
– Other associated features
eg uveitis, inflammatory
bowel disease, enthesitis,
Ankylosing spondylitis
Monoarthritis - differential
diagnosis
Reactive arthritis
• Prodromal GI /GU
Infection eg
campylobacter,
salmonella, shigella,
Yersinia,chlamydia
• Pustular psoriasis
and circinate balanitis
Monoarthritis - differential
diagnosis
– Trauma - # and haemarthroses (warfarin,
bleeding disorders)
– Palindromic rheumatism – 24-48 hours
inflammatory monoarthritis, can evolve into
polyarthritis eg RA
Others to think about
•
•
Osteonecrosis/AVN (steroids/alcohol)
Severe pain but good ROM
•
Monoarticular RA
•
Monoarticular OA
•
Prosthetic joint - loosening, # or infection
•
Periarticular pathology
Articular vs periarticular?
Is it an articular or extra-articular
problem?
• ARTICULAR
PERI-ARTICULAR
•
•
•
•
•
pain in plane of tendon
active > passive
linear swelling
localised tenderness
localised erythema/heat
pain all planes
active = passive
capsular swelling/effusion
joint line tenderness
diffuse erythema/heat
Olecranon bursitis
Septic arthritis
• 15-30 per 100,000 population
• Fatal in 11% of cases in UK
• Delayed or inadequate treatment leads to
irreversible joint damage
How do you get septic arthritis?
Pathogenesis
Who gets septic arthritis?
Who gets septic arthritis?
•
•
•
•
common organisms
Staphylococci or
Streptococcus
young adults,
significant incidence
gonococcal arthritis
Elderly &
immunocompromised
gram -ve organisms
Anaerobes more
common with
penetrating trauma
Who gets septic arthritis?
•
pre-existing joint disease
•
prosthetic joints
•
low SE status, IV drug abuse, alcoholism
•
diabetes, steroids, immunosuppression
•
previous intra-articular steroid injection
Who gets septic arthritis?
• Skin lesions e.g. ulcers, particularly in context
RA often source of infection
• poor prognostic features: older, pre-existing joint
disease & presence of synthetic material within
joint
What are the signs and
symptoms of septic
arthritis?
Symptoms & signs of septic arthritis
• Typically hot, swollen, red
tender joint with reduced
range of movement,
difficulty weight bearing
• Systemic upset
• Night and rest pain
• Symptoms usually
present for < 2/52
• Large joints more
commonly affected than
small
• majority of joint sepsis in
hip or knee
Symptoms & signs of septic arthritis
• In pre-existing inflammatory joint disease
symptoms in affected joint(s), out of proportion
to disease activity in other joints.
• 10-15% of cases, > one joint - so polyarticular
presentation does not exclude sepsis
• presence of fever not reliable indicator- if
clinical suspicion high - treat
What investigations are useful
in septic arthritis?
Investigations
• Synovial fluid aspiration
– volume/viscosity/cellularity/
appearance
– gram stain/culture
– Absence of organism does
not exclude septic arthritis
– polarised light microscopy
(crystals)
– NB suspected prosthetic
joint sepsis should
ALWAYS be referred to
orthopaedics
Investigations
• Always blood cultures
• significant proportion blood cultures + ve in
absence of + ve synovial fluid cultures
• FBC ESR & CRP
• BUT absence of raised WBC, ESR or CRP
not exclude diagnosis of sepsis - if clinical
suspicion high always treat
Other investigations
• CRP useful for monitoring response to
treatment
• Urate may be normal in acute gout and of
no diagnostic value in acute gout or sepsis
• Measure urea, electrolytes & liver function
for end organ damage (poor prognostic
feature)
• Renal function may influence antibiotic
choice
Other tests?
•
•
•
If skin pustule is present, suggestive of
gonococcal infection, then skin swab
should be taken
If history suggests possibility of
genitourinary or respiratory tract infection
then culture sputum (and CXR) & urine &
take anogenital & throat swabs where
appropriate
If periarticular sepsis – appropriate
swabs and cultures
Imaging
• Plain X rays no benefit in diagnosis but form
baseline for any future joint damage. May
show chondrocalcinosis.
• MRI useful in distinguishing sepsis from OA
but less good between sepsis &
inflammation
• MRI sensitive for osteomyelitis
Imaging
• Ultrasound useful in guiding needle
aspiration eg hip
• White cell scanning helpful in diagnosing
prosthetic sepsis
Antibiotic treatment of septic arthritis
• Local and national guidelines
• Liaise with micro. guided by gram stain
• Conventionally given iv for 2 weeks or until
signs improve, then orally for around 4
weeks
Joint drainage & surgical options
• medical aspiration, surgical aspiration via
arthroscopy or open arthrotomy
• Suspected hip sepsis – early orthopaedic
referral – may need urgent open
debridement
Recommendations specific to 1o care & emergency
department
• commonest hot joint to present in 1o care is 1st MTP
gout
• usually diagnosed on clinical grounds without
needle aspiration or referral to hospital. (Make
referral if inadequate recovery)
• Some GPs aspirate & inject joints for inflammatory
arthritis or osteoarthritis. If withdraw
pus/unexpected cloudy fluid should send sample
with patient to local emergency department
Recommendations specific to 1o care & emergency
department
• GPs & doctors in EAU should refer patients
with suspected septic arthritis to specialist
with expertise to aspirate joint. May be
orthopaedic surgeon or rheumatologist
• Admit if sepsis is suspected or confirmed.
Summary
• with a short history of a hot, swollen,
tender joint (or joints) plus restriction of
movement; septic arthritis until proven
otherwise
• If clinical suspicion high investigate &
treat as septic arthritis even in absence of
fever
THANK-YOU