Chronic multifocal osteomyelitis, unsp tibia and fibula

This code signifies a persistent, widespread infection of the bone and bone marrow affecting multiple, unspecified sites within the tibia and fibula. It indicates a long-standing inflammatory process, often characterized by periods of remission and exacerbation, without specifying laterality.

Use this code when documentation clearly states "chronic multifocal osteomyelitis" involving the tibia and fibula, and the specific bone (tibia or fibula) or laterality (right/left) is not specified. This code is appropriate when the infection has been ongoing for an extended period, typically weeks to months, and affects more than one distinct area within these lower leg bones.

• Avoid using this code if the laterality (right or left) or the specific bone (tibia or fibula) is documented; instead, use a more specific code from the M86.36 series.
• Ensure the documentation supports the "chronic" nature of the osteomyelitis, as acute osteomyelitis (M86.1-) or subacute osteomyelitis (M86.2-) would be coded differently.
• Always look for documentation of the causative organism (e.g., Staphylococcus aureus) to potentially add a secondary code from B95-B97, if applicable.