We present basic differences in the musculoskeletal ultrasound examinations between adults and children. Examiners who deal with adults on a daily basis have shared concerns about examining children. Such concerns may arise from the different approach to child ultrasounds, but they also come from differences in anatomical characteristics according to developmental age. We discuss the presence of growth plates, as well as non-mineralized parts of the bones. We also refer to the pathologies most often found in ultrasounds in early developmental stages. In the PubMed database, the set of keywords: “msk ultrasound in children”, “pediatric msk sonoanatomy”, “coxitis fugax”, “pediatric Baker’s cyst”, “Baker’s cyst ultrasonography”, “bone septic necrosis in ultrasonography”, “ultrasonography in juvenile idiopathic arthritis”, and “ultrasonography in juvenile spondyloarthropathies”, was used to identify a total of 1657 results, from which 54 was selected to be included in the article. We discuss the problem of osteochondritis dissecans, Osgood-Schlatter disease, examples of ligament injuries (especially in relation to the knee and ankle joints), exfoliation of growth cartilages, osteochondroma, exudates and inflammations affecting joints, and Baker’s cysts. In this way, we have collected useful information about the most common diseases of the musculoskeletal system in children.

Recurrent fever syndromes are autoinflammatory diseases. In their pathogenesis, no autoantibodies or autoreactive T-lymphocytes are found. Innate immunity and adaptive immunity are of great importance in this case. In the mid-latitudes, the most common syndrome is periodic fever with aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA), which mainly affects children under 5 years of age. Fevers occur cyclically, on average every 26–36 days. Characteristic features of PFAPA include the absence of any symptoms between fever episodes and undisturbed growth and development of the child. In laboratory tests, during a fever episode, elevated white blood cell count and an increase in inflammatory markers are observed. The recommended treatment is the use of glucocorticoids. In some cases, the use of colchicine or even an interleukin-1 receptor antagonist (anakinra) may be considered. The aim of this paper is to present the case of a 3.5-year-old boy hospitalised in the Department of Paediatrics, Nephrology and Paediatric Allergology of the Military Institute of Medicine due to recurrent episodes of fever with enlarged lymph nodes, occurring at regular intervals, as well as to draw attention to the difficulties encountered during the diagnosis of recurrent febrile episodes.

Streptococcus agalactiae bacteria are a common cause of neonatal sepsis and meningitis. Universal screening of pregnant women for carriage and intrapartum antibiotic prophylaxis has significantly reduced the disease prevalence in children up to 7 days of age. However, it is to be remembered that group B streptococcal infection can also affect older children, even if their mothers have tested negative for Streptococcus agalactiae during pregnancy or underwent complete perinatal antibiotic prophylaxis. This paper presents a clinical case of a 3-month-old boy treated for sepsis and Streptococcus agalactiae meningitis. The baby was born on time, with normal body weight. The infection occurred despite full maternal ampicillin perinatal therapy in the mother.