All ICD10 Codes

G21

Non-Billable
ChapterG00–G99
Rankcategory
Official Description

Secondary parkinsonism

Use a more specific code (6 billable, 1 non-billable)
G21.0Malignant neuroleptic syndromeG21.1Other drug-induced secondary parkinsonismhas subcodesG21.2Secondary parkinsonism due to other external agentsG21.3Postencephalitic parkinsonismG21.4Vascular parkinsonismG21.8Other secondary parkinsonismG21.9Secondary parkinsonism, unspecified
Metadata & Insights
  • •Non-billable category (requires more specific sub-code).
  • •Chapter 6: Diseases of the Nervous System (G00-G99).

CH6 Parent Instructions

Excludes2(Not included here. Code separately if applicable.)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Instructional Notes

Excludes1(Not coded here. Use a different code.)
  • Huntington's disease (G10)
  • neurocognitive disorder with Lewy bodies (G31.83)
  • Shy-Drager syndrome (G90.3)
  • syphilitic Parkinsonism (A52.19)

Clinical Hierarchy

BillableHas subcodes
CH6Diseases of the nervous system (G00-G99)
G20-G26Extrapyramidal and movement disorders (G20-G26)
G21Secondary parkinsonismNot billable
G21.0Malignant neuroleptic syndromeBillable
G21.1Other drug-induced secondary parkinsonismSubcodes
G21.2Secondary parkinsonism due to other external agentsBillable
G21.3Postencephalitic parkinsonismBillable
G21.4Vascular parkinsonismBillable
G21.8Other secondary parkinsonismBillable
G21.9Secondary parkinsonism, unspecifiedBillable

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to G21:

chapterCH6
Diseases of the nervous system (G00-G99)
View context instructions

MS-DRG Classification

2026

No direct MS-DRG triggers identified.

Cross Reference

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