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A 28-year-old black woman with sickle cell anemia is evaluated for a 2-day history of progressive left ankle pain. Her pain is so severe she is now using crutches to ambulate. She has no history of inciting trauma. She is sexually active. Joint pain has been a manifestation of her sickle cell crises since adolescence.
On physical examination, she is afebrile. The left ankle is warm and swollen. On musculoskeletal examination, there is pain with passive flexion and extension of the ankle joint. Squeezing the midfoot does not elicit pain.
Arthrocentesis of the ankle yields 2 mL of yellow fluid (leukocyte count, 18,000/µL [18 × 109/L]; 88% neutrophils). Polarized light microscopy of the fluid shows no crystals, and Gram stain for bacterial organisms is negative. Results of fluid cultures are pending.
Which of the following conditions should be initially treated in this patient?
A Sickle cell arthropathy
B Avascular necrosis
C Gouty arthritis
D Septic arthritis
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hi neutro count,hi wbc,,must be septic arthritis,but nothn on gram stain.
sickle cell s possible.
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Correct Answer D
Septic arthritis should be suspected and empirically treated in all patients with otherwise unexplained acute inflammatory mono- or oligoarthritis.
Prompt management of suspected septic arthritis is indicated for this patient. Septic arthritis should be suspected and empirically treated in all patients with otherwise unexplained acute inflammatory mono- or oligoarthritis if crystals are not seen on synovial fluid analysis.
Disseminated gonococcal infection, as well as infection with staphylococcus or streptococcus, should be considered in patients who are sexually active. Involvement of a single joint and the presence of inflammatory fluid are consistent with septic arthritis, and systemic symptoms, such as fever, may be absent. A diagnosis of gonococcal infection may be confirmed with positive cervical, pharyngeal, or rectal cultures, whereas synovial fluid culture is the gold standard for diagnosing other bacterial infections.
A negative Gram stain for bacteria does not exclude infection; in some series, Gram stain for nongonococcal bacteria was negative in >50% of patients with established nongonococcal septic arthritis. Synovial fluid Gram stain is even less sensitive in diagnosing gonococcal infection.
Multifocal avascular necrosis that may involve the ankle is a frequent complication of sickle cell disease, but synovial fluid in this setting would not be inflammatory. Gout is more likely to develop in patients with sickle cell anemia compared with the age-matched general population, most likely because sickle cell anemia“related increased hematopoietic cell turnover and occult interstitial renal disease cause hyperuricemia. However, diagnosis of gout cannot be definitively established in the absence of crystals on synovial fluid analysis.
Acute sickle cell arthritis is characterized by pain, inflammatory synovial fluid, and synovial infarction, but infection must be excluded before this diagnosis can be established. Negative culture of synovial fluid in the absence of previous antibiotic use or a failure to respond to appropriate antibiotic therapy generally excludes infection. Treatment of acute sickle cell arthritis is symptomatic.
