Systemic atrophies primarily affecting central nervous system in diseases classified elsewhere (G13) ICD-10-CM
The G13 code range covers systemic atrophies primarily affecting central nervous system in diseases classified elsewhere with 5 ICD-10-CM diagnosis codes. 4 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Codes in the G13 Range 5 codes · 4 billable
- G13 Systemic atrophies primarily affecting central nervous system in diseases classified elsewhereNon-billable
- G13.0 Paraneoplastic neuromyopathy and neuropathy
- G13.1 Other systemic atrophy primarily affecting central nervous system in neoplastic disease
- G13.2 Systemic atrophy primarily affecting the central nervous system in myxedema
- G13.8 Systemic atrophy primarily affecting central nervous system in other diseases classified elsewhere
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the G13 range.
Paraneoplastic Cerebellar Degeneration
Cerebellar degeneration associated with a remote neoplasm. Clinical manifestations include progressive limb and GAIT ATAXIA; DYSARTHRIA; and NYSTAGMUS, PATHOLOGIC. The histologic type of the associated neoplasm is usually carcinoma or lymphoma. Pathologically the cerebellar cortex and subcortical nuclei demonstrate diffuse degenerative changes. Anti-Purkinje cell antibodies (anti-Yo) are found in the serum of approximately 50% of affected individuals. (Adams et al., Principles of Neurology, 6th ed, p686)
About the G13 Code Range
ICD-10 code section G13 covers systemic atrophies that primarily affect the central nervous system but occur as part of other diseases classified elsewhere. These codes are used to document neurological degeneration linked to various underlying medical conditions, including cancers and endocrine disorders.
This group includes specific codes like G13.0 for paraneoplastic neuromyopathy and neuropathy, which involves nerve damage related to cancers such as multiple myeloma or plasma cell dyscrasias—often described using terms like paraneoplastic peripheral neuropathy or neuropathy associated with dysproteinemias. Code G13.1 refers to other systemic atrophies affecting the CNS tied to neoplastic diseases, including paraneoplastic cerebellar degeneration, sometimes called secondary cerebellar degeneration. G13.2 applies to systemic atrophy from myxedema, a severe form of hypothyroidism, with no listed synonyms. Finally, G13.8 captures other systemic CNS atrophies due to various diseases elsewhere, also linked with terms like myxedema cerebellar degeneration. These ICD-10 codes enable precise classification of neurological decline when it arises secondary to systemic or neoplastic disorders.
Questions About This Page
How many billable codes are in the G13 range?
Of the 5 codes in this range, 4 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the G13 range classify?
The range classifies systemic atrophies primarily affecting central nervous system in diseases classified elsewhere. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
