I41 Myocarditis in diseases classified elsewhere

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

Excludes1 (never code together)

• myocarditis (in):
• Chagas' disease (chronic) (B57.2)
• acute (B57.0)
• coxsackie (virus) infection (B33.22)
• diphtheritic (A36.81)
• gonococcal (A54.83)
• influenzal (J09.X9, J10.82, J11.82)
• meningococcal (A39.52)
• mumps (B26.82)
• rheumatoid arthritis (M05.31)
• sarcoid (D86.85)
• syphilis (A52.06)
• toxoplasmosis (B58.81)
• tuberculous (A18.84)

Code first

• underlying disease, such as:
• typhus (A75.0-A75.9)

Applies from I41 Myocarditis in diseases classified elsewhere

Excludes1 (never code together)

• myocarditis (in):
• Chagas' disease (chronic) (B57.2)
• acute (B57.0)
• coxsackie (virus) infection (B33.22)
• diphtheritic (A36.81)
• gonococcal (A54.83)
• influenzal (J09.X9, J10.82, J11.82)
• meningococcal (A39.52)
• mumps (B26.82)
• rheumatoid arthritis (M05.31)
• sarcoid (D86.85)
• syphilis (A52.06)
• toxoplasmosis (B58.81)
• tuberculous (A18.84)

Code first

• underlying disease, such as:
• typhus (A75.0-A75.9)

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 422.0 Acute myocarditis in diseases classified elsewhere (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Manifestation codes as principal diagnosis: Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and are not allowed as principal diagnosis.

Diagnosis Index entries for I41

• Myocarditis (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile) › in (due to) › epidemic louse-borne typhus
• Myocarditis (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile) › in (due to) › typhus NEC

Nearby codes

• I41 Myocarditis in diseases classified elsewhere (this code)