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Emergency F i lesAnalysis of the synovial fluid is interpreted
basedon the gross appearance, colour, viscosity, WBC count,and Gram
stain results. Traditionally, the cutoff valuefor synovial WBC
count for diagnosis of septic arthritis
has been greater than SOOOO/mm ,- however, lower WBCcounts can
occur early in infectious arthritis or in partiallytreated
infections.^ High WBC counts can occur in rheu-matoid arthritis,
gout, and pseudogout. Therefore, cellcount should not be used to
rule out a septic etiology.
Other markers that are frequently discussed in syno-vial fluid
analysis are decreased glucose and increasedsynovial protein;
however, the discriminating abilitiesof these tests are very poor
and they are no longer rou-tinely recommended in the workup of a
septic joint.'^RecommendationsThe goal of treatment is to rapidly
eradicate the infectionand protect the joint. It is universally
accepted that anti-biotics should be promptly administered once the
diag-nosis is strongly suspected. The currently recommendedchoice
of antibiotics is a third-generation cephalosporinor vancomycin if
MRSA is a concern.' For patients whoare allergic to cephalosporins,
a luoroquinolone,such aslevofloxacin or ciprofloxacin, is
suggested.'
The literature is unclear as to how long intravenousantibiotics
should be continued. Most protocols recom-mend an intravenous
course of 2 to 4 weeks' durationfollowed by an additional 2 to 6
weeks of oral antibiotics.Septic arthritis is an orthopedic
emergency. Therecontinues to be controversy regarding medical
versussurgical joint decompression. Medical managementconsists of
needle aspiration of the joint. If pus reac-cumulates, repeat
aspiration is performed. Surgicaldrainage is accomplished by
arthrotomy or arthros-copy and the possible placement of tubes to
drain thejoint. No randomized controlled studies have evalu-ated
joint drainage procedures compared with no-drainage
procedures.ConclusionMortality from septic arthritis is reported to
be between8% and 1596.' Unfortunately, this has not changed
dra-matically despite the advent of intravenous antibiot-ics. The
patient's outcome depends on a host of factors,such as previous
joint damage, the virulence of theinfecting organism, and the speed
with which adequatetreatment is begun.
This patient must be considered to have septic arthritisuntil
proven otherwise. It is critical to promptly diagnoseand treat the
joint infection, which has a potentially dev-astating course. As
laboratory tests are neither sensitiveno r specific in diagnosing
or excluding septic arthritis,arthrocentesis and syno vialfiuid
analysis are mandatory.Give the patient broad-spectrum antibiotics
immediately
IBOnOM LINE
j Bacterial arth ritis is the most dangerous formof acute
monoarthritis; it can result in cartilagedestruction, septicemia,
anil death within a few daysif unrecognized. Prompt
dicritical.Laboratory tests are neicific in diagnosing or e>
gnosis and treatment arether sensitive nor spe-cluding septic
arthritis.Arthrocentesis and synovial fluid analysis are man-datory
for this differential.Immediately give broad-spectrum antibiotics
to at-risk patients and consult an orthopedic surgeon.
POINTS SAILLANTSL'arthrite bactrienne est la forme la plus
dange-reuse de la mono-arthrite aigu; elle peut causerla
destruction du cartilage, une septicmie et lamort en quelques jours
seulement si elle n'est pasreconnue. Il est essentiel de poser un
diagnostic etd'administrer un traitement sans dlai.Les analyses de
labpratoiiie ne sont ni sensibles nispcifiques pour poser ou carter
un diagnosticd'arthrite septique. Il est obligatoire de procder une
arthrocentse et une analyse du liquide syno-vial pour le diagnostic
d iffrentiel.Il faut administrer immdiatement un antibiotique large
spectre aux patients risque et consulter unchirurgien
orthopdique.
Dr V isser is Medicai Director of Emergency and Trauma Services
at theThunder Bay Regionai Heaith Sciences Centre in O ntario. Dr
Tupper is anattending physician in the emergency department at
Banff iVIineral SpringsHospital in Aiberta. 'Competing
interestsNone declared iR e fe r e n c e s .1. Margaretten ME,
Kohlwes J, Moore D, Bent S. Does this adult patient haveseptic
arthritis? JAMA 2007;297( 13): 1478|.88.2. Dubost II, Soubrier M,
De Champs C, Ristori JM, Bussire JL, Sauvezie B. Nochanges in the
distribu tion o f organisms responsible for septic arthritis over
a20 year period. An n Rheum D is 2002;6i (3):267-9.3. K aandorp CJ,
Van Schaardenburg D, Krijnen P, Habbema JD, van de l.aar MA.Risk
factors for septic arthritis in patients with joint disease. A
prospectivestudy Arihritis Rheum 1995;38(12):i819f25.4. Li SF,
Henderson J, Dickman E, Darzynkiiewica R. Laboratory tests in
adults
with monoarticular arthritis: can they rule out a septic joint.
Acad Emerg M ed2004;ll(3):276-80. 
