In children, osteomyelitis is usually acute and hematogenous, the metaphysis of long bones being the most common location. Common symptoms include limb pain and fever. Essential investigations include laboratory tests measuring inflammation, and blood culture. Although osteomyelitis is initially undetectable by plain X-ray, the investigation is nevertheless necessary, e.g. in order to exclude fractures. Magnetic resonance imaging is useful especially in cases of suspected complications. A bone scan is utilized in unclear cases. Treatment of the disease is started with an intravenous antimicrobial medication directed against the most common causative agent, Staphylococcus aureus.