Acute nonspecific idiopathic pericarditis

This code signifies an acute inflammation of the pericardium (the sac surrounding the heart) that is not caused by a specific identifiable etiology and is not secondary to another known condition. It presents with sudden onset of chest pain, often relieved by leaning forward, and may be accompanied by fever and pericardial friction rub.

Use this code when documentation clearly indicates a diagnosis of acute pericarditis without an identified underlying cause (e.g., infection, autoimmune disease, trauma, myocardial infarction). Supporting documentation should include clinical findings consistent with acute pericarditis and negative workup for specific etiologies.

• Ensure the "idiopathic" and "nonspecific" aspects are clearly documented. If a specific cause is identified, a more specific code for pericarditis due to that cause should be used.
• Do not use this code for chronic or recurrent pericarditis; separate codes exist for those conditions.
• Consider sequencing if pericarditis is a manifestation of another primary condition (e.g., systemic lupus erythematosus); in such cases, the underlying condition would typically be coded first.