Secondary pneumonic plague

This code represents pneumonic plague that develops as a secondary complication of another form of plague, such as bubonic or septicemic plague. It signifies the progression of the infection to involve the lungs, leading to severe respiratory symptoms and high mortality if untreated.

Use this code when documentation clearly indicates a patient has developed pneumonic plague following an initial diagnosis of another form of plague. Supporting documentation should detail the primary plague infection and the subsequent onset of pulmonary involvement, including respiratory symptoms and diagnostic findings.

• Ensure documentation specifies "secondary" pneumonic plague, distinguishing it from primary pneumonic plague.
• Sequence this code as the principal diagnosis if it is the reason for the admission or encounter.
• Code the underlying form of plague (e.g., bubonic plague) as an additional diagnosis if still active.