Pyogenic sacroiliitis - A comparison between paediatric and adult patients

Background. Pyogenic sacroiliitis is a rare cause of hip pain and fever. We aim to report a series of 33 patients with pyogenic sacroiliitis and to investigate the differences among paediatric and adult cases. Methods. Clinical and laboratory data of 33 cases who were admitted to the emergency department with a confirmed discharge diagnosis of pyogenic sacroiliitis between 1996 and 2005 were assessed. All patients were divided into paediatric and adult groups by the age of 15 yr. The features of pyogenic sacroiliitis and clinical outcome were compared among the two groups. Several factors were analysed including gender, age, clinical signs and symptoms, laboratory tests, radiological examinations and scintigraphy. Results. Among the all included patients, females were attacked more frequently than males (3: 1). One-third of patients had concurrent infections, of which urinary tract infections were the most common (41.6%). Compared with adult patients, paediatric patients tend to have fewer comorbid immunocompromized conditions, fewer concurrent infections, more equality in gender distribution and more presentations of weight bearing difficulty. Staphylococcus aureus was the main blood culture isolate from paediatric patients (80%), but only accounted for half of those from adult patients. Group B streptococcus and Salmonella spp. were not uncommon in the adult patients. Scintigraphic bone scan has the highest sensitivity (93.3%) and remains the image modality of choice. When local abscess formation is suspected, computed tomography or magnetic resonance imaging may be the preferred method used for examination. Conclusion. This case series should alert the physicians to the possibility of pyogenic sacroiliitis and the difference between paediatric and adult patients.