Osteomyelitis in Sickle Cell Anemia: Does Age Predict Risk of Salmonella Infection?

BACKGROUND:Osteomyelitis is a condition that disproportionately affects those with sickle cell anemia (SCA). Despite the frequency of osteomyelitis in this population, there are reports of increasing life expectancy and rates of Staphylococcus aureus infections, which contrasts the belief that Salmonella is the most common organism identified. The purpose of this systematic review is to determine the most commonly identified organism and identify whether age is associated with the development of Salmonella osteomyelitis in homozygous sickle cell patients.METHODS:A search of PubMed, EMBASE Cochrane and databases was performed for studies of all levels of evidence pertaining to osteomyelitis in SCA. Reasons for exclusion included non-English language, case reports, literature reviews, isolated septic arthritis without bony involvement and isolated oral-facial bony involvement.RESULTS:The most common pathogen cultured was nontyphoid Salmonella , which occurred in 117 of 192 (60.9%) of cases identified. This was followed by S. aureus 41 of 192 (21.8%) and other enteric bacteria 14 of 192 (7.2%). Subgroup analysis demonstrated differences at the age of initial presentation with Salmonella cohort at 6.8 years and S. aureus cohort at 22.1 years ( P = 0.0001). On geographic analysis, African countries had an older average age of diagnosis at 13.1 years with decreased rates of Salmonella infections and increased rates of infections from other organisms compared with the US, Middle East and Europe.CONCLUSIONS:This systematic review suggests that Salmonella is most commonly identified in patients with SCA (HbSS phenotype) especially those <12 years old presenting with acute osteomyelitis. Sub-Saharan African countries had later ages of diagnosis compared with the US, Middle East and Europe with bacterial profiles that favors a diagnosis of chronic osteomyelitis and missed acute initial presentation. Therefore, age of presentation is likely a surrogate for geographic and socioeconomic factors such as availability of medical screening and treatment.