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Three Part Question

In [adults presenting to the ED with an acute, hot joint] is the [absence of fever] sufficient [to rule out septic arthritis]?

Clinical Scenario

A 32 year old woman with a 10 year history of rheumatoid arthritis (RA), treated with long-term, low dose oral prednisolone, presents to the emergency department with a 2-day history of a red, swollen left knee that is painful to touch. She reports no prior knee swelling, recent trauma, skin infection, knee surgery, illegal drug use or risky sexual behavior. On examination, she is afebrile, has an effusion and restricted movement in her left knee. You wonder if this is just another exacerbation of her RA? You order blood tests and deliberate whether the absence of fever is enough to rule out septic arthritis (SA)?

Search Strategy

Multi-file searching using OVID interface- Medline (1950-2008), Embase (1980-2008), CINAL (1982-2008), Cochrane ({[exp fever OR exp body temperature OR exp high temperature OR high adj temperature OR high adj fever OR fever.mp OR febrile .mp OR pyrexia$.mp OR afebrile .mp OR apyrexia$.mp] AND [exp. Arthritis, Infectious OR hotjoint.mp OR septic joint.mp]}) Limited to Humans, English Language and Adults. Bibliographic references found in these articles were also examined to identify related literature.

Search Outcome

The following number of articles were identified from each of the databases: Medline 282 citations, Embase 340 citations, CINHAL 4 citations, Cochrane 5 citations. Duplicates and irrelevant titles removed from 631 articles leaving a total of ten relevant articles.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Gavet F, et al 2005 USA	335 cases of adult SA; 206 over 60 and 42 over 80	Retrospective Cohort (Level 2)	Absence of fever	13-19% of patients aged 60 and older and 23% of patients aged 80. 20-30% with serious infection had no fever	Small sample size for the over 80. Selection Bias-not note of how temperature was collected
Schelapbach P, et al 1990 Switzerland	43 cases diagnosed with SA	Case Series (Level 3)	Absence /Presence of fever	<37.0 -13/37 (35%) 37.0-37.5 4/37 (11%)	Small sample, no power calculation. No note of how diagnosis was made. No note of different subsets of patients involved( i.e. Chronic rheumatic disease, prosthetic joints or immunocompromised)
Ross J.J, et al. 2003 USA	99 cases of SA of the pubic symphsis during the past 30 years identified using Pubmed and one novel case	Review (Level 1)	Presence of Fever(temperature>38)	53/72 (74% ) of patients with recorded temperature	Search strategy not transparent. Search not extensive, Medline, Cochrane, CINHAL, Embase or not used. No manual searches of grey literature made. Narrow population studies
Naushad A, et al. 2006 Pakistan	116 patients admitted under the ICD 711 to have SA or diagnosed on the clinical basis to have SA: swelling, erythema, limitation of movement and physician assessment.	Case Series/ Retrospective Analysis (Level 3)	Presence of Fever	60.3%	Case Series Collection bias-No definition of fever and no note of how and when it was measured

Comment(s)

The classical presentation of septic arthritis (SA) is an acutely swollen, painful joint with limited range of motion, where chills and fever are common but not always present. [1] The quality of evidence to support the absence or presence of fever in SA is limited to retrospective studies. The lack of the sensitivity and specificity of the gold standard used for the diagnosis of SA, culture and/or gram stain, contributes to a difficulty in drawing conclusions from the evidence. The best evidence available for this clinical question was a recent systematic review, “Does the Adult Patient Have Septic Arthritis”. Given the sensitivity, almost half of the patients with SA will not present with fever, and the absence of fever clearly does not rule out infection. Given the poor specificity, the presence of fever does not help the clinician rule in arthritis.[1] Similarly, the other nine listed papers note an absence of fever in SA. Therefore a high index of suspicion should be maintained by the clinician in the presentation of the acute hot joint despite an absence of fever. Furthermore, there may be more value in the absence of symptoms such as joint pain and swelling ruling out SA as they offer a higher sensitivity in predicting SA than fever( 85%; 95%CI, 78-90 and 78%; 95% CI, 71-85 respectively).[1]

Editor Comment

RB

Clinical Bottom Line

The absence of fever is not sensitive enough to rule out septic arthritis. *Imperfect Gold Standard –gram stain (sensitivity 29-50%) and culture (sensitive-82%)[1] References 1. Margaretten ME. Does the Adult Patient Have Septic Arthritis? JAMA 2007;297(13):1478-1488.

References

1. Gavet F, et al. Septic arthritis in patients aged 80 and older:a comparison with younger adults. Journal of American Geriatrics Society 2005;1210-1203
2. Schlapbach P, et al. Bacterial arthritis: are fever, rigors, leucocytosis and blood cultures of diagnostic value? Clinical Rheumatology 1990:69-72
3. Ross J.J, et al Septic arthritis of the pubic symphysis:review of 100 cases Medicine(Baltimore) 2003;340-345
4. Naushad A, et al. Septic arthritis in a tertiary care hospital Journal of Pakistan Medical Association 2006;95-98
5. Martens P, et al. Septic arthritis in adults: clinical features, outcome, and intensive care requirements. Journal of Intensive Care Medicine 1995;246-252