2026 ICD-10-CM Diagnosis Code A52.05Other cerebrovascular syphilis

ICD-10-CM Codes›A00–B99›A50-A64›A52

ICD-10-CM A52.05
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A52.05 is a billable ICD-10-CM diagnosis code for other cerebrovascular syphilis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 314 through 316. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 96 closely related codes. Coders also document this condition as rupture of syphilitic cerebral aneurysm. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other and ill-defined cerebrovascular disease and Sexually transmitted infections (excluding HIV and hepatitis).

Code Identity

ICD-10-CM Code
A52.05
Billable Status
Yes — Valid for Submission
Code Describes
Other cerebrovascular syphilis
Short Description
Other cerebrovascular syphilis
Same as the full description in the CMS dataset.
Parent Code
A52.0
Cardiovascular and cerebrovascular syphilis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA50-A64Infections with a predominantly sexual mode of transmission
CategoryA52Late syphilis
This CodeA52.05Other cerebrovascular syphilis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Rupture of syphilitic cerebral aneurysm
  • Syphilitic aneurysm

Tabular List NotesGuidance

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

Inclusion Terms

  • Syphilitic cerebral aneurysm (ruptured) (non-ruptured)
  • Syphilitic cerebral thrombosis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

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

CCSR CIR024
Other and ill-defined cerebrovascular disease
Default principal diagnosis: inpatient No · outpatient No
CCSR INF010
Sexually transmitted infections (excluding HIV and hepatitis)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Brain Diseases

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body.

Read the full article at MedlinePlus

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

Convert A52.05 to ICD-9-CMHistory

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

ICD-9-CM
093.89 Cardiovascular syph NEC
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 A52.05Overview

What is the ICD-10 code for other cerebrovascular syphilis?

The ICD-10-CM code for other cerebrovascular syphilis is A52.05 (sometimes written as A5205). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is A52.05 (Cardiovascular and cerebrovascular syphilis) a billable code?

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

What MS-DRG does A52.05 group to?

When other cerebrovascular syphilis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 314, 315, 316, with relative weights from 0.6821 to 2.0852 depending on complications. Higher weights mean higher Medicare reimbursement.

Is A52.05 a CC or MCC?

CMS lists A52.05 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 96 closely related codes in its exclusion list.

What is the ICD-9 equivalent of A52.05?

Under the General Equivalence Mappings, other cerebrovascular syphilis converts to ICD-9-CM 093.89 (cardiovascular syph NEC). The mapping is approximate, so confirm the match fits the documentation.