ICD-10-CM Alphabetic Index · FY 2026 23 Entries
Parkinsonism in the ICD-10-CM Index ICD-10-CM
The main term Parkinsonism (idiopathic) (primary) carries 23 index entries pointing to 10 ICD-10-CM codes. The default entry is G20.C, the code the bare main term maps to; every indented line below refines the term by site, cause, or type. Verify any candidate code in the Tabular List before using it.
✓ Built from the official CMS FY 2026 index fileEffective Oct 1, 2025 – Sep 30, 2026
23
Index Entries
10
Codes Referenced
G20.C
Default Code
P
Letter
23 of 23 shown
ICD-10-CM
Index Entries Under Parkinsonism 23 entries · 10 codes
Parkinsonism (idiopathic) (primary) G20.C
with neurogenic orthostatic hypotension (symptomatic) G90.3
arteriosclerotic G21.4
dementia G20.C see also Dementia, in, diseases specified elsewhere
with behavioral disturbance G20.C see also Dementia, in, diseases specified elsewhere
due to
drugs NEC G21.19
neuroleptic G21.11
medication-induced NEC G21.19
neuroleptic induced G21.11
postencephalitic G21.3
secondary G21.9
due to
arteriosclerosis G21.4
drugs NEC G21.19
neuroleptic G21.11
encephalitis G21.3
external agents NEC G21.2
syphilis A52.19
specified NEC G21.8
syphilitic A52.19
treatment-induced NEC G21.19
vascular G21.4
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Related Index Terms
Source: Centers for Medicare & Medicaid Services, FY 2026 ICD-10-CM Index to Diseases and Injuries release files, effective October 1, 2025 through September 30, 2026.
