LAUSR

Pyomyositis is a bacterial infection of skeletal muscle characterised by the formation of intramuscular abscesses. Although it is an entity that originated in tropical regions, there has been an increase in its incidence in regions with a temperate climate in recent years. It occurs more frequently in adult patients with chronic conditions,1 so its diagnosis in the paediatric population requires a high index of suspicion.1--5 Our aim was to describe the characteristics of pyomyositis in the paediatric population. To do so, we conduced a retrospective descriptive study of patients aged less than 15 years that received a diagnosis of pyomyositis in our hospital over a period of 12 years (2004--2015). We reviewed medical records for the purpose of analysing clinical, epidemiological, diagnostic and treatment data, which we did using the software Microsoft Excel ® 2010. We included a total of 15 patients, 8 girls and 7 boys, with a median age of 4.5 years (interquartile range [IQR], 1.3--7 years). All were of Spanish descent and had acquired the infection in Spain; none of the cases were imported. Furthermore, none of the patients were immunosuppressed or had chronic disease. Thirteen patients (87%) had primary pyomyositis, of whom 7 (54%) reported previous trauma in the involved region. Two patients had pyomyositis secondary to sacroiliitis and contiguous skin infection. The muscles involved most frequently were those in the lower extremities (10 children, 67%), mainly the quadriceps femoris (5 patients) and the iliopsoas (2 patients). The rest of the cases involved the upper extremities and the cervical musculature (2 patients each). There was 1 case with infection in multiple locations, with involvement of both quadriceps, the left calf and the right adductor magnus, soleus, biceps brachii and pronator teres. The most frequent presenting symptoms