G31.85

HCC Category Mapping

What This Code Means

Corticobasal degeneration is a rare progressive brain disorder that causes gradual loss of nerve cells in specific areas of the brain, leading to problems with movement, balance, and cognitive function. Patients typically experience stiffness, jerky movements, and difficulty with coordination that worsens over time.

Coding Tips

• •This code represents a neurodegenerative disease; ensure documentation clearly indicates corticobasal degeneration diagnosis rather than similar conditions like Parkinson's disease or progressive supranuclear palsy
• •Code G31.85 is specific to corticobasal degeneration; do not use more general codes like G31.83 (Dementia with Lewy bodies) unless the patient has a confirmed dual diagnosis

Clinical Significance

Corticobasal degeneration is a rare progressive neurodegenerative disorder affecting the cerebral cortex and basal ganglia. It causes asymmetric motor dysfunction, cognitive decline, and distinctive features like alien limb phenomenon. Due to its rarity and complex presentation, it is frequently misdiagnosed, making documentation specificity critical for accurate risk adjustment.

Documentation Requirements

• ✓Provider documentation explicitly stating corticobasal degeneration or corticobasal syndrome
• ✓Neurological examination documenting asymmetric motor findings (rigidity, dystonia, myoclonus)
• ✓Neuroimaging (MRI) showing asymmetric cortical atrophy
• ✓Documentation of characteristic features: alien limb phenomenon, apraxia, cortical sensory loss
• ✓Evidence that other conditions (Parkinson's, progressive supranuclear palsy) have been considered and ruled out
• ✓Current treatment plan addressing motor and cognitive symptoms

Commonly Confused Codes