Other disorders of nervous system in diseases classified elsewhere (G99) ICD-10-CM
The G99 code range covers other disorders of nervous system in diseases classified elsewhere with 4 ICD-10-CM diagnosis codes. 3 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 G99 Range 4 codes · 3 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the G99 range.
Neuroschistosomiasis
SCHISTOSOMIASIS of the brain, spinal cord, or meninges caused by infections with trematodes of the genus SCHISTOSOMA (primarily SCHISTOSOMA JAPONICUM; SCHISTOSOMA MANSONI; and SCHISTOSOMA HAEMATOBIUM in humans). S. japonicum infections of the nervous system may cause an acute meningoencephalitis or a chronic encephalopathy. S. mansoni and S. haematobium nervous system infections are associated with acute transverse myelitis involving the lower portions of the spinal cord. (From Joynt, Clinical Neurology, 1998, Ch27, pp61-2)
Syringomyelia
Longitudinal cavities in the spinal cord, most often in the cervical region, which may extend for multiple spinal levels. The cavities are lined by dense, gliogenous tissue and may be associated with SPINAL CORD NEOPLASMS; spinal cord traumatic injuries; and vascular malformations. Syringomyelia is marked clinically by pain and PARESTHESIA, muscular atrophy of the hands, and analgesia with thermoanesthesia of the hands and arms, but with the tactile sense preserved (sensory dissociation). Lower extremity spasticity and incontinence may also develop. (From Adams et al., Principles of Neurology, 6th ed, p1269)
About the G99 Code Range
ICD-10 codes in the G99 category cover a range of nervous system disorders that occur as complications of other diseases. These codes specify conditions affecting the nervous system due to underlying causes classified elsewhere in medical records.
The ICD-10 code G99 is a general category for nervous system disorders linked to other diseases. For example, G99.0 specifically codes for autonomic neuropathy, which involves nerve damage affecting involuntary body functions and can arise from various conditions such as endocrine diseases, autoimmune disorders, or nutritional deficiencies. This includes well-known terms like "autoimmune ganglionopathy" or "autonomic neuropathy due to Fabry disease," helping coders identify the correct diagnosis code when these synonyms appear. Meanwhile, G99.2 addresses myelopathy, a disorder of the spinal cord caused by factors like nutritional deficiencies, metabolic problems, or neoplasms. It includes conditions such as "syringomyelia" and "cervical myelopathy," covering a wide spectrum of spinal cord complications associated with other illnesses. Finally, G99.8 encompasses other specified nervous system disorders caused by underlying diseases and includes examples like "neuroschistosomiasis" and "peripheral neuropathy due to metabolic disorder."
Questions About This Page
How many billable codes are in the G99 range?
Of the 4 codes in this range, 3 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 G99 range classify?
The range classifies other disorders of 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.
