2026 ICD-10-CM Diagnosis Code B57.42Meningoencephalitis in Chagas' disease

ICD-10-CM Codes›A00–B99›B50-B64›B57

ICD-10-CM B57.42
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B57.42 is a billable ICD-10-CM diagnosis code for meningoencephalitis in Chagas' disease. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 867 through 869. Coders also document this condition as Chagas' disease with nervous system involvement. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Encephalitis; and Parasitic, other specified and unspecified infections.

Code Identity

ICD-10-CM Code
B57.42
Billable Status
Yes — Valid for Submission
Code Describes
Meningoencephalitis in Chagas' disease
Short Description
Meningoencephalitis in Chagas' disease
Same as the full description in the CMS dataset.
Parent Code
B57.4
Chagas' disease (chronic) with nervous system involvement

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB50-B64Protozoal diseases
CategoryB57Chagas' disease
This CodeB57.42Meningoencephalitis in Chagas' disease

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Chagas' disease with nervous system involvement
  • Meningitis due to Chagas disease
  • Meningoencephalitis due to Chagas disease
  • Trypanosoma cruzi encephalitis
  • Trypanosomiasis with encephalitis
  • Trypanosomiasis with meningitis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Chagas'(-Mazza) disease (chronic)
      • with
        • nervous system involvement
          • meningoencephalitis
    • Encephalitis(chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute)
      • in (due to)
        • Chagas' disease (chronic)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS002
Encephalitis
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR INF009
Parasitic, other specified and unspecified infections
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Chagas Disease

Chagas disease, or American trypanosomiasis, is an illness that can cause serious heart and stomach problems. It is caused by a parasite. Chagas disease is common in Latin America, especially in poor, rural areas. It can also be found in the United States, most often in people who were infected before they moved to the U.S.

The full article covers:

  • What is Chagas disease?
  • What causes Chagas disease?
  • Who is more likely to develop Chagas disease?
  • What are the symptoms of Chagas disease?
  • How is Chagas disease diagnosed?
  • What are the treatments for Chagas disease?
  • Can Chagas disease be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert B57.42 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
086.1 Chagas dis of oth organ
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About B57.42Overview

Is B57.42 (Chagas' disease (chronic) with nervous system involvement) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report meningoencephalitis in Chagas' disease on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does B57.42 group to?

When meningoencephalitis in Chagas' disease is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 868, 869, with relative weights from 0.7297 to 2.0932 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of B57.42?

Under the General Equivalence Mappings, meningoencephalitis in Chagas' disease converts to ICD-9-CM 086.1 (Chagas dis of oth organ). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.