ICD-10/G21.0

G21.0 ICD 2026 Code: Malignant neuroleptic syndrome

G21.0 is the authoritative medical code for Malignant neuroleptic syndrome. This classification is used in medical billing and clinical recording to specify the clinical criteria for malignant neuroleptic syndrome (ICD-10-CM G21.0), ensuring healthcare documentation aligns with 2026 federal coding standards.

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

Official Registry Overview & Definition

Malignant neuroleptic syndrome is a billable ICD-10-CM diagnosis code G21.0. Excludes1 (not coded here): neuroleptic induced parkinsonism G21.11; Huntington's disease G10; neurocognitive disorder with Lewy bodies G31.83; Shy-Drager syndrome G90.3; syphilitic Parkinsonism A52.19. Use additional code: code for adverse effect, if applicable, to identify drug (T43.3X5, T43.4X5, T43.505, T43.595).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for G21.0 in the official ICD-10-CM tabular list.

Excludes1 — Not Coded Here

Conditions that can never be reported with this code; the two are mutually exclusive.

  • neuroleptic induced parkinsonism G21.11
  • Huntington's disease G10
  • neurocognitive disorder with Lewy bodies G31.83
  • Shy-Drager syndrome G90.3
  • syphilitic Parkinsonism A52.19

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • code for adverse effect, if applicable, to identify drug (T43.3X5, T43.4X5, T43.505, T43.595)

Frequently Asked Questions (FAQ) & Clinical Guidance

What can't be coded together with G21.0?

Per Excludes1 instructions, G21.0 must not be reported with: neuroleptic induced parkinsonism (G21.11); Huntington's disease (G10); neurocognitive disorder with Lewy bodies (G31.83); Shy-Drager syndrome (G90.3).

Is an additional code needed with G21.0?

Use additional code(s) to specify: code for adverse effect, if applicable, to identify drug (T43.3X5, T43.4X5, T43.505, T43.595).

Codes in This Family (7)

Official ICD-10-CM classifications in the same code family as G21.0, with their registry titles.

  • G21 — Secondary parkinsonism
  • G21.1 — Other drug-induced secondary parkinsonism
  • G21.2 — Secondary parkinsonism due to other external agents
  • G21.3 — Postencephalitic parkinsonism
  • G21.4 — Vascular parkinsonism
  • G21.8 — Other secondary parkinsonism
  • G21.9 — Secondary parkinsonism, unspecified

Indexed Clinical Terms (1)

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.

  • Syndrome, malignant, neuroleptic

Related Codes & Numerical Sequence (Crawl Map)

Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures:

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