Can Serum Procalcitonin Be Helpful In Diagnosing Bone And Joint Infections?
Osteomyelitis and septic arthritis can lead to significant morbidity and mortality. Prompt identification and treatment of these disorders can lessen the bone and joint destruction associated with these infections.
However, the diagnosis of osteomyelitis and septic arthritis is often delayed due to mimicking pathologies including Charcot arthropathy and gouty arthropathy. Other inflammatory markers including white blood count (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) lack specificity, and can be elevated in non-infectious pathologies including trauma, rheumatic disease, inflammatory arthropathies and Charcot arthropathy.1 While clinicians often consider positive bone and synovial fluid cultures the gold standard, they can have false negative results secondary to the administration of empiric antibiotics, and can take up to two to three days to complete.
Procalcitonin is a relatively novel inflammatory marker that can aid in the diagnosis of osteomyelitis and septic arthritis. Procalcitonin is the precursor of the thyroid hormone calcitonin. It is produced under normal conditions in the C cells of the thyroid gland. Normal levels of procalcitonin are <0.10ng/mL. Procalcitonin has a high specificity and its levels rise rapidly in bacterial infections, but procalcitonin remains low in viral infections and inflammatory disorders.2-6
Clinicians initially utilized procalcitonin to differentiate bacterial from viral meningitis but it has had gradually widening indications including:
• identifying bacterial etiology of shock and respiratory distress;
• differentiation of infected pancreatitis from uncomplicated pancreatitis; • early detection of postoperative infection; and
• diagnosis of septic arthritis and osteomyelitis.7-10
Researchers have found that procalcitonin has a high specificity (98 percent) for bacterial infection but poor sensitivity, making it a useful rule-in test rather than rule-out test for bacterial infections.11 Additionally, one can use procalcitonin as a guide for starting and monitoring treatment with antibiotics.12,13
Seeing the utility of procalcitonin as a rapid and accurate test for bacterial infections, Maharajan and colleagues evaluated the use of procalcitonin in the diagnosis of septic arthritis and acute osteomyelitis.10 This study found serum procalcitonin at a cutoff of 0.4 ng/mL to be a sensitive (85.2 percent) and specific (87.3 percent) marker in the diagnosis of septic arthritis and acute osteomyelitis.10 Greeff examined the use of procalcitonin in the diagnosis of osteomyelitis and septic arthritis, and found procalcitonin to be a useful aid in the diagnosis of these infections with procalcitonin more specific for bacterial infections that CRP.14 In a meta-analysis, Shen and coworkers examined the use of procalcitonin for the diagnosis of septic arthritis and osteomyelitis, and found this test to be a useful aid for rule-in diagnosis rather than exclusion of these infectious pathologies.15
Researchers have demonstrated that procalcitonin is a useful tool in the diagnosis of septic arthritis and acute osteomyelitis. This test remains a better aid in the rule-in diagnosis rather than exclusion of both of these disorders. Further research is needed to identify the ideal cutoff value for procalcitonin and lower cutoff values may improve the diagnostic effectiveness of procalcitonin.
References
1. Bitik B, Mercan R, Tufan A, et al. Differential diagnosis of elevated erythrocyte sedimentation rate and C-reactive protein levels: a rheumatology perspective. Eur J Rheumatol. 2015;2(4):131-134.
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3. Chan YL, Tseng CP, Tsay PK, Chang SS, Chiu TF, Chen JC. Procalcitonin as a marker of bacterial infection in the emergency department: an observational study. Crit Care. 2004;8(1):R12-20.
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8. Rau B, Steinbach G, Gansauge F, Mayer JM, Grunert A, Beger HG. The potential role of procalcitonin and interleukin 8 in the prediction of infected necrosis in acute pancreatitis. Gut. 1997;41(6):832-840.
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10. Maharajan K, Patro DK, Menon J, et al. Serum procalcitonin is a sensitive and specific marker in the diagnosis of septic arthritis and acute osteomyelitis. J Orthop Surg Res. 2013;8:19.
11. Oppegaard O, Skodvin B, Halse AK, Langeland N. CD64 as a potential biomarker in septic arthritis. BMC Infect Dis. 2013;13:278.
12. Oh JS, Kim SU, Oh YM, et al. The usefulness of the semiquantitative procalcitonin test kit as a guideline for starting antibiotic administration. Am J Emerg Med. 2009;27(7):859-863.
13. Holub M, Rozsypal H, Chalupa P. [Procalcitonin: a reliable marker for the diagnosis and monitoring of the course of bacterial infection]. Klin Mikrobiol Infekc Lek. 2008;14(6):201-208.
14. Greef E. Is procalcitonin useful in diagnosing septic arthritis and osteomyelitis in children? Orthopaedic Proceedings. 2013;95-B(29Supp):37-37.
15. Shen CJ, Wu MS, Lin KH, et al. The use of procalcitonin in the diagnosis of bone and joint infection: a systemic review and meta-analysis. Eur J Clin Microbiol Infect Dis. 2013;32(6):807-814.
