Hemoglobinopathy and pattern of musculoskeletal infection in children

The bacterial pathogens associated with osteomyelitis in patients with hemoglobinopathy (HbSS) are controversial. There is insufficient data on the common musculoskeletal (MSS) infections in patients with hemoglobinopathies and the associated bacterial pathogens in Nigeria. To identify the common MSS infections in children and the associated bacterial pathogens, especially in those with abnormal hemoglobin genotypes. A retrospective case review was done of pediatric and adolescent patients admitted with bone and soft tissue infections over a seven-year period in a Nigerian teaching hospital. One-hundred-nineteen patients were studied, with mean age 7.9+/-5.6 years and male-female ratio of 1.3:1. Out of 78 patients with known genotype, 62.8% had HbAA, 20.5% HbSS, 9% HbAS, and 7.7% HbAC. The most common MSS infections were osteomyelitis (64.7%), pyomyositis (17.6%), and septic arthritis (10.1%). Others were cellulitis (5.9%), tuberculous arthritis (0.8%), and necrotizing fasciitis (0.8%). Staphylococcus aureus (S. aureus) was isolated from 62% of chronic osteomyelitis (COM) and 58% of pyomyositis, while gram-negative bacilli accounted for 34% and 42%, respectively. S. aureus was isolated from 63% of patients with HbAA, 40% with HbSS, 58% with HbAS, and 58% with HbAC, while gram-negative bacilli accounted for 33%, 60%, 33%, and 33%, respectively. Osteomyelitis and pyomyositis appear to be similarly common in patients with and without HbSS (RR 1.29; 95% CI 0.47-3.50). Osteomyelitis and soft tissue infections in general also appear to be equally common in them (RR 1.16; 95% CI 0.39-4.11). However, osteomyelitis appears to be more common among patients with HbSS than those with HbAA (RR 2.29; 95% CI 0.58-8.99) and those with other hemoglobinopathies (RR 2.23; 95% CI 0.66-7.49) Osteomyelitis, pyomyositis and septic arthritis are common MSS infections in hospitalized pediatric and adolescent patients, while tuberculous arthritis is uncommon. The most common bacterial pathogen in these infections is S. aureus-even in patients with HbSS and other hemoglobinopathies. Gram-negative bacilli are important causes of MSS infections in hospitalized children with HbSS. HbSS may be an independent risk factor for osteomyelitis in these patients.