2027 ICD-10-CM Diagnosis Code A51.43Secondary syphilitic oculopathy

ICD-10-CM Codes›A00–B99›A50-A64›A51

ICD-10-CM A51.43
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

A51.43 is a billable ICD-10-CM diagnosis code for secondary syphilitic oculopathy. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 124 through 125. 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 79 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified eye disorders and Sexually transmitted infections (excluding HIV and hepatitis).

Code Identity

ICD-10-CM Code
A51.43
Billable Status
Yes — Valid for Submission
Code Describes
Secondary syphilitic oculopathy
Short Description
Secondary syphilitic oculopathy
Same as the full description in the CMS dataset.
Parent Code
A51.4
Other secondary syphilis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA50-A64Infections with a predominantly sexual mode of transmission
CategoryA51Early syphilis
This CodeA51.43Secondary syphilitic oculopathy

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral iritis due to secondary syphilis
  • Bilateral iritis of eyes caused by Treponema pallidum
  • Bilateral retinitis of eyes caused by Treponema pallidum
  • Chorioretinitis due to secondary syphilis
  • Chorioretinitis of bilateral eyes due to secondary syphilis
  • Chorioretinitis of left eye due to secondary syphilis
  • Chorioretinitis of right eye due to secondary syphilis
  • Infectious secondary iridocyclitis
  • Infectious secondary iritis
  • Iritis of left eye caused by Treponema pallidum
  • Iritis of right eye caused by Treponema pallidum
  • Left iritis due to secondary syphilis
  • Left syphilitic retinitis
  • Posterior uveitis due to infectious disease
  • Retinitis of bilateral eyes due to secondary syphilis
  • Retinitis of eye due to secondary syphilis
  • Right iritis due to secondary syphilis
  • Right syphilitic retinitis
  • Secondary syphilis of eye
  • Secondary syphilitic iridocyclitis
  • Syphilitic chorioretinitis
  • Syphilitic choroiditis
  • Syphilitic disseminated retinochoroiditis
  • Syphilitic infectious intermediate uveitis
  • Syphilitic iritis
  • Syphilitic retinitis
  • Uveitis due to secondary syphilis

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to A51.43: its own notes plus those printed at block A50-A64 and Chapter 1. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Secondary syphilitic chorioretinitis
  • Secondary syphilitic iridocyclitis, iritis
  • Secondary syphilitic uveitis

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Block A50-A64 Infections with a predominantly sexual mode of transmission applies to 142 codes
  • nonspecific and nongonococcal urethritis (N34.1)
  • Reiter's disease (M02.3-)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block A50-A64 Infections with a predominantly sexual mode of transmission applies to 142 codes
  • human immunodeficiency virus [HIV] disease (B20)
From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • carrier or suspected carrier of infectious disease (Z22.-)
  • certain localized infections - see body system-related chapters
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)
  • influenza and other acute respiratory infections (J00-J22)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • code to identify resistance to antimicrobial drugs (Z16.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name A51.43, its category, or a range that includes it.

Applicable To 1

These notes mention A51.43.

  • O98.1 Syphilis complicating pregnancy, childbirth and the puerperium
    Conditions in A50-A53 names A50-A53, which includes this code

Excludes1 1

These codes carry an Excludes1 note naming A51.43: they are not reported together with it, unless the two conditions are unrelated.

  • H20.0 Acute and subacute iridocyclitis
    iridocyclitis, iritis, uveitis (due to) (in) syphilis (A51.43)

Excludes2 2

These codes carry an Excludes2 note naming A51.43: its condition is not part of those codes, and both may be reported when the patient has both.

  • Chapter 7 (H00-H59) Diseases of the eye and adnexa
    syphilis related eye disorders (A50.01, A50.3-, A51.43, A52.71)
  • Block A65-A69 Other spirochetal diseases
    syphilis (A50-A53) names A50-A53, which includes this code

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 EYE012
Other specified eye disorders
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

Eye Infections

Your eyes can get infections from bacteria, fungi, or viruses. Eye infections can occur in different parts of the eye and can affect just one eye or both. Two common eye infections are:

Read the full article at MedlinePlus

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

Convert A51.43 to ICD-9-CMHistory

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

ICD-9-CM
091.50 Syphilitic uveitis NOS
Approximate The match is approximate rather than exact.
ICD-9-CM
091.51 Syphilit chorioretinitis
Approximate The match is approximate rather than exact.
ICD-9-CM
091.52 Syphilitic iridocyclitis
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About A51.43Overview

What is the ICD-10 code for secondary syphilitic oculopathy?

The ICD-10-CM code for secondary syphilitic oculopathy is A51.43 (sometimes written as A5143). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is A51.43 (Other secondary syphilis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report secondary syphilitic oculopathy on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does A51.43 group to?

When secondary syphilitic oculopathy is the principal diagnosis on an inpatient stay, it groups to MS-DRG 125, 124, with relative weights from 0.7699 to 1.2470 depending on complications. Higher weights mean higher Medicare reimbursement.

Is A51.43 a CC or MCC?

CMS lists A51.43 as a CC (complication or comorbidity) for FY 2027. 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 79 closely related codes in its exclusion list.

Can A51.43 be reported with N34.1?

Not as a rule. The Excludes1 note at block A50-A64, which applies to A51.43, lists "nonspecific and nongonococcal urethritis (N34.1)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).