I30.9 Acute pericarditis, unspecified

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from I30 Acute pericarditis

Includes

• acute mediastinopericarditis
• acute myopericarditis
• acute pericardial effusion
• acute pleuropericarditis
• acute pneumopericarditis

Excludes1 (never code together)

• Dressler's syndrome (I24.1)
• rheumatic pericarditis (acute) (I01.0)
• viral pericarditis due to Coxsackie virus (B33.23)

MS-DRG index

Defines the logic of DRG(s) 314-316 in MDC 05.

Approximate ICD-9-CM (GEMs)

• 420.90 Acute pericarditis, unspecified (approximate)
• 420.99 Other acute pericarditis (approximate)

Code annotations containing back-references to I30.9

Back-references to I30.9

• Type 1 Excludes: I31.3 Pericardial effusion (noninflammatory) ("acute pericardial effusion (I30.9)")

Back-references to I30

• Type 1 Excludes: I01.0 Acute rheumatic pericarditis ("acute pericarditis not specified as rheumatic (I30.-)")

Diagnosis Index entries for I30.9

• Chylopericardium › acute
• Mediastinopericarditis › acute
• Pericarditis (with decompensation) (with effusion) › acute (hemorrhagic) (nonrheumatic) (Sicca)
• Pericarditis (with decompensation) (with effusion) › cholesterol (chronic) › acute
• Pericarditis (with decompensation) (with effusion) › neoplastic (chronic) › acute
• Pleuropericarditis › acute
• Pneumopericarditis › acute

Nearby codes

• I30 Acute pericarditis
• I30.0 Acute nonspecific idiopathic pericarditis
• I30.1 Infective pericarditis
• I30.8 Other forms of acute pericarditis
• I30.9 Acute pericarditis, unspecified (this code)