Acute monoarthropathy

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Acute monoarthropathy

• Jaya Ravindran
• Rheumatologist

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Aims

• an approach to the investigation and differential
  diagnosis of acute monoarticular pain
• focus on septic and crystal arthritis

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Acute Monoarthritis - differential diagnosis

• Septic arthritis
• Crystal arthritis
• Gout (uric acid)
• Pseudogout/calcium pyrophosphate deposition
  disease (CPPD)

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• What are other differentials for
• acute monoarticular pain?

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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

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Monoarthritis - differential diagnosis

• Reactive arthritis
• Prodromal GI /GU
• Infection eg
• campylobacter,
• salmonella, shigella,
• Yersinia,chlamydia
• Pustular psoriasis
• and circinate balanitis

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Monoarthritis - differential diagnosis

• Trauma - and haemarthroses (warfarin, bleeding
  disorders)
• Palindromic rheumatism 24-48 hours inflammatory
  monoarthritis, can evolve into polyarthritis eg
  RA

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Others to think about

• Osteonecrosis/AVN (steroids/alcohol)
• Severe pain but good ROM
• Monoarticular RA
• Monoarticular OA
• Prosthetic joint - loosening, or infection
• Periarticular pathology

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• Articular vs periarticular?

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Is it an articular or extra-articular problem?

• ARTICULAR PERI-ARTICULAR
• pain all planes pain in plane of tendon
• active passive active gt passive
• capsular swelling/effusion linear swelling
• joint line tenderness localised tenderness
• diffuse erythema/heat localised erythema/heat

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Olecranon bursitis
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Septic arthritis

• 15-30 per 100,000 population
• Fatal in 11 of cases in UK
• Delayed or inadequate treatment leads to
  irreversible joint damage

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• How do you get septic arthritis?

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Pathogenesis
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• Who gets septic arthritis?

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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

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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

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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

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• What are the signs and
• symptoms of septic
• arthritis?

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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 lt 2/52
• Large joints more commonly affected than small
• majority of joint sepsis in hip or knee

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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, gt one joint - so polyarticular
  presentation does not exclude sepsis
• presence of fever not reliable indicator- if
  clinical suspicion high - treat

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• What investigations are useful
• in septic arthritis?

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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

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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

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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

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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

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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

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Imaging

• Ultrasound useful in guiding needle aspiration eg
  hip
• White cell scanning helpful in diagnosing
  prosthetic sepsis

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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

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Joint drainage surgical options

• medical aspiration, surgical aspiration via
  arthroscopy or open arthrotomy
• Suspected hip sepsis early orthopaedic referral
  may need urgent open debridement

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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
  

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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.

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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

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• THANK-YOU