Other degenerative diseases of nervous system, not elsewhere classified (G31)

Browse all the diagnosis codes used for other degenerative diseases of nervous system, not elsewhere classified (g31). For easy navigation, the diagnosis codes are sorted in alphabetical order and grouped by sections. Each section is clearly marked with its description, and the corresponding three-digit code range. This format makes it simple to browse diagnosis codes in this chapter or section and find what you're looking for. We've also added green checkmark icons to label billable codes, and red warning icons for non-billable ones. This makes it easy to identify which codes can be billed.

Clinical Information

Alexander Disease - Rare leukoencephalopathy with infantile-onset accumulation of Rosenthal fibers in the subpial, periventricular, and subependymal zones of the brain. Rosenthal fibers are GLIAL FIBRILLARY ACIDIC PROTEIN aggregates found in ASTROCYTES. Juvenile- and adult-onset types show progressive atrophy of the lower brainstem instead. De novo mutations in the GFAP gene are associated with the disease with propensity for paternal inheritance.

Corticobasal Degeneration - Rare progressive neurological disorder characterized by Parkinsonism, cortical atrophy of multiple areas of the brain including the cerebral cortex and the basal ganglia, cognitive dysfunction and eye movement abnormalities.

Frontotemporal Dementia - The most common clinical form of FRONTOTEMPORAL LOBAR DEGENERATION, this dementia presents with personality and behavioral changes often associated with disinhibition, apathy, and lack of insight.

Frontotemporal Lobar Degeneration - Heterogeneous group of neurodegenerative disorders characterized by frontal and temporal lobe atrophy associated with neuronal loss, gliosis, and dementia. Patients exhibit progressive changes in social, behavioral, and/or language function. Multiple subtypes or forms are recognized based on presence or absence of TAU PROTEIN inclusions. FTLD includes three clinical syndromes: FRONTOTEMPORAL DEMENTIA, semantic dementia, and PRIMARY PROGRESSIVE NONFLUENT APHASIA.

Instructional Notations

Use Additional Code

The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.

• code, if applicable, for codes G31.0 G31.83 G31.85 G31.9
• dementia with anxiety F02.84 F02.A4 F02.B4 F02.C4
• dementia with behavioral disturbance F02.81 F02.A1 F02.B1 F02.C1
• dementia with mood disturbance F02.83 F02.A3 F02.B3 F02.C3
• dementia with psychotic disturbance F02.82 F02.A2 F02.B2 F02.C2
• dementia without behavioral disturbance F02.80 F02.A0 F02.B0 F02.C0
• mild neurocognitive disorder due to known physiological condition F06.7

Type 2 Excludes

A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

• Reye's syndrome G93.7