2026 ICD-10-CM Diagnosis Code A39.1Waterhouse-Friderichsen syndrome

ICD-10-CM Codes›A00–B99›A30-A49›A39

ICD-10-CM A39.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A39.1 is a billable ICD-10-CM diagnosis code for Waterhouse-Friderichsen syndrome. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 870 through 872. Coders also document this condition as adrenal hemorrhage. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Other specified and unspecified endocrine disorders.

Code Identity

ICD-10-CM Code
A39.1
Billable Status
Yes — Valid for Submission
Code Describes
Waterhouse-Friderichsen syndrome
Short Description
Waterhouse-Friderichsen syndrome
Same as the full description in the CMS dataset.
Parent Code
A39
Meningococcal infection

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA30-A49Other bacterial diseases
CategoryA39Meningococcal infection
This CodeA39.1Waterhouse-Friderichsen syndrome

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adrenal hemorrhage
  • Adrenocortical hemorrhage
  • Waterhouse-Friderichsen syndrome

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Meningococcal hemorrhagic adrenalitis
  • Meningococcic adrenal syndrome

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.

    • Adrenalitis, adrenitis
      • meningococcal, hemorrhagic
    • Apoplexia, apoplexy, apoplectic
      • adrenal
    • Disease, diseased
      • Waterhouse-Friderichsen
    • Friderichsen-Waterhouse syndrome or disease
    • Infection, infected, infective(opportunistic)
      • meningococcal
        • adrenals
    • Meningococcus, meningococcal
      • adrenalitis, hemorrhagic
    • Sepsis(generalized) (unspecified organism)
      • adrenal hemorrhage syndrome (meningococcal)
    • Syndrome
      • adrenal
        • hemorrhage (meningococcal)
    • Syndrome
      • adrenal
        • meningococcic
    • Syndrome
      • Friderichsen-Waterhouse
    • Syndrome
      • septicemic adrenal hemorrhage
    • Syndrome
      • Waterhouse (-Friderichsen)
    • Waterhouse(-Friderichsen) syndrome or disease (meningococcal)

Clinical ClassificationClinical

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

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient No · outpatient No
CCSR END015
Other specified and unspecified endocrine disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Adrenal Hemorrhage

    hemorrhage and necrosis of the adrenal gland tissue. bilateral and extensive hemorrhage may lead to acute adrenal insufficiency, shock, and death.

Patient EducationClinical

Adrenal Gland Disorders

Your adrenal glands are two small organs that sit on top of each kidney. The adrenal glands make different types of hormones you need to stay alive and healthy. Hormones are chemicals that travel in your bloodstream and control how different parts of your body work.

The full article covers:

  • What are adrenal glands?
  • What are adrenal gland disorders?
  • What causes adrenal gland disorders?
  • How are adrenal gland disorders diagnosed?
  • What are the treatments for adrenal gland disorders?

Read the full article at MedlinePlus

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

Convert A39.1 to ICD-9-CMHistory

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

ICD-9-CM
036.3 Meningococc adrenal synd
Exact Match The mapping is direct, with no qualifiers.

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 A39.1Overview

Is A39.1 (Meningococcal infection) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report Waterhouse-Friderichsen syndrome on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does A39.1 group to?

When Waterhouse-Friderichsen syndrome is the principal diagnosis on an inpatient stay, it groups to MS-DRG 870, 871, 872, with relative weights from 1.0233 to 6.9118 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of A39.1?

Under the General Equivalence Mappings, Waterhouse-Friderichsen syndrome converts to ICD-9-CM 036.3 (meningococc adrenal synd). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.