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G90.522 ICD-10-CM Code: Complex regional pain syndrome I of left lower limb

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
5 Excludes1

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 073 — CRANIAL AND PERIPHERAL NERVE DISORDERS WITH MCC (MDC 01)
  • MS-DRG 074 — CRANIAL AND PERIPHERAL NERVE DISORDERS WITHOUT MCC (MDC 01)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G90.522 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on G90.522 itself; “inherited from” names the category or block whose note applies here.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Coder workflow for G90.522

MedCoder structured workflow — derived from this code’s own official record

Before you code G90.522

  1. Laterality is coded in this family. Confirm the side documented — right, left, or bilateral — and select the matching code (this page’s code: left). The unspecified-side code applies only when the record states no side. Laterality is assigned from the documented side; where a bilateral code exists and both sides are documented, it is used instead of two unilateral codes (Guidelines I.B.13).

    ReviewG90.521 · right, G90.529 · unspecified

    Guide: Laterality coding →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with G90.522. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support a condition named in G90.522’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewG57.7, G56.4, G31.2

  2. Is the side documented?
    Yes → Select the code for the documented side (or the bilateral code when both sides are documented and one exists).
    No → Use the unspecified-side code only when the record states no side; a query is the alternative.

    ReviewG90.521 · right, G90.529 · unspecified

Consider G90.522. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
Laterality
Right, left or bilateral as documented; unspecified only when the record states no side (Guidelines I.B.13).

Official instructions as workflow

  • Excludes1 — check before selecting G90.522(5 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with G90.522: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareG57.7, G56.4, G31.2

    See the official tabular notes · Guidelines I.A.12.a

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: Both the condition G90.522 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewG57.7, G56.4, G31.2

Documentation: The record documents the condition on one side only.

Coding question: Which code in this family applies?

Path: Select the sibling code for the documented side.

Reason: Laterality is assigned from the documented side; the unspecified-side code is for records that state no side (Guidelines I.B.13).

ReviewG90.521 · right, G90.529 · unspecified

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Don’t confuse G90.522 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of G90.522 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • G57.7— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of causalgia of lower limb moves the case to G57.7; the two are not reported together unless documented as unrelated.

    Full comparison: G90.522 vs G57.7 →

  • G56.4— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of causalgia of upper limb moves the case to G56.4; the two are not reported together unless documented as unrelated.

    Full comparison: G90.522 vs G56.4 →

  • G31.2— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of dysfunction of the autonomic nervous system due to alcohol moves the case to G31.2; the two are not reported together unless documented as unrelated.

    Full comparison: G90.522 vs G31.2 →

  • G90.529— Specificity relationship (Review)

    Overlapping diagnoses in the same category.

    Overlapping codes in the same category — the documentation decides which is the more specific fit.

    What moves you there: A record that documents no more than “Complex regional pain syndrome I of unspecified lower limb” takes G90.529; specificity in the record moves it back here.

    Full comparison: G90.522 vs G90.529 →

  • G90.521— Laterality relationship (Review)

    Same condition; these differ only in which side is documented.

    The same condition on the other side; the documented side decides, and a bilateral code, where one exists, replaces the pair when both sides are documented.

    What moves you there: A documented right side moves the case to G90.521.

    Full comparison: G90.522 vs G90.521 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Code Overview

Complex regional pain syndrome I of left lower limb is a billable ICD-10-CM diagnosis code (G90.522).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Verify Before Coding

  • CC as a secondary diagnosis (FY2027). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name G90.522 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 4 Excludes1 notes across 2 chapters: G56.4 — Causalgia of upper limb (via G90.52.-), G57.7 — Causalgia of lower limb (via G90.52.-), G89.2 — Chronic pain, not elsewhere classified (via G90.5.-), M89.0 — Algoneurodystrophy (via G90.5.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 156 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 2 MS-DRGs: DRG 073 (MDC 01), DRG 074 (MDC 01).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):NVS019 — Nervous system pain and pain syndromes (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

G90.01 — Carotid sinus syncope, G90.09 — Other idiopathic peripheral autonomic neuropathy, G90.2 — Horner's syndrome, G90.4 — Autonomic dysreflexia, G90.50 — Complex regional pain syndrome I, unspecified, G90.511 — Complex regional pain syndrome I of right upper limb, G90.512 — Complex regional pain syndrome I of left upper limb, G90.513 — Complex regional pain syndrome I of upper limb, bilateral, G90.519 — Complex regional pain syndrome I of unspecified upper limb, G90.521 — Complex regional pain syndrome I of right lower limb, G90.523 — Complex regional pain syndrome I of lower limb, bilateral, G90.529 — Complex regional pain syndrome I of unspecified lower limb, G90.59 — Complex regional pain syndrome I of other specified site, G90.81 — Serotonin syndrome, G90.89 — Other disorders of autonomic nervous system, G90.9 — Disorder of the autonomic nervous system, unspecified, G90.B — LMNB1-related autosomal dominant leukodystrophy, G93.1 — Anoxic brain damage, not elsewhere classified, G93.40 — Encephalopathy, unspecified, G93.41 — Metabolic encephalopathy, +135 more

Same condition, opposite side

Same category and title, differing only in which side of the body is affected.

G90.521 — Complex regional pain syndrome I of right lower limb (right)Compare G90.522 vs G90.521 →, G90.529 — Complex regional pain syndrome I of unspecified lower limb (unspecified)Compare G90.522 vs G90.529 →

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Nervous system pain and pain syndromes).

G89.21 — Chronic pain due to trauma, G89.22 — Chronic post-thoracotomy pain, G89.28 — Other chronic postprocedural pain, G89.29 — Other chronic pain, G89.3 — Neoplasm related pain (acute) (chronic), G89.4 — Chronic pain syndrome, G90.2 — Horner's syndrome, G90.50 — Complex regional pain syndrome I, unspecified, G90.511 — Complex regional pain syndrome I of right upper limb, G90.512 — Complex regional pain syndrome I of left upper limb, G90.513 — Complex regional pain syndrome I of upper limb, bilateral, G90.519 — Complex regional pain syndrome I of unspecified upper limb, G90.521 — Complex regional pain syndrome I of right lower limb, G90.523 — Complex regional pain syndrome I of lower limb, bilateral, G90.529 — Complex regional pain syndrome I of unspecified lower limb, G90.59 — Complex regional pain syndrome I of other specified site, M51.361 — Other intervertebral disc degeneration, lumbar region with lower extremity pain only, M51.362 — Other intervertebral disc degeneration, lumbar region with discogenic back pain and lower extremity pain, M51.371 — Other intervertebral disc degeneration, lumbosacral region with lower extremity pain only, M51.372 — Other intervertebral disc degeneration, lumbosacral region with discogenic back pain and lower extremity pain, +4 more

Contextual Map

Every relationship of G90.522 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run G90.522 with these 4 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

  • G56.4 — Causalgia of upper limb[Excludes1](via G90.52.-): “complex regional pain syndrome I of lower limb (G90.52-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • G57.7 — Causalgia of lower limb[Excludes1](via G90.52.-): “complex regional pain syndrome I of lower limb (G90.52-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • G89.2 — Chronic pain, not elsewhere classified[Excludes1](via G90.5.-): “reflex sympathetic dystrophy (G90.5-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • M89.0 — Algoneurodystrophy[Excludes1](via G90.5.-): “reflex sympathetic dystrophy (G90.5-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 01 — Diseases and Disorders of the Nervous System[MDC crossing]: “Diseases and Disorders of the Nervous System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 8,919 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Nearest codes (26)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "G90.522 — Complex regional pain syndrome I of left lower limb." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/g90.522-complex-regional-pain-syndrome-i-of-left-lower-limb

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Complex regional pain syndrome I of left lower limb

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G90.522 in its code family, with their registry titles.

View all codes in the G90 family