G81.10 Spastic hemiplegia affecting unspecified side

ICD-10-CM Code G81.10: Spastic hemiplegia affecting unspecified side

ICD-10-CM code G81.10 represents spastic hemiplegia affecting an unspecified side. Spastic hemiplegia involves involuntary muscle overactivity, including increased muscle tone and spasms, and can occur as a sequela of central nervous system damage like stroke. More specific codes in this category distinguish whether the right or left side is affected and whether it is dominant or nondominant. 1 2 3

Plain-language overview

Spastic hemiplegia is a sequela following damage to the central nervous system, such as from stroke, traumatic brain injury, or autoimmune diseases. It involves upper limb dysfunction and positive signs of the upper motor neuron syndrome identified as involuntary muscle overactivity. 1 2

Involuntary muscle overactivity in spasticity includes a velocity-dependent increase in muscle tone, spasms, clonus, spastic dystonia, and co-contracting muscle activation. Spasticity classified as hemispastic affects the arm and leg on one body side. 2

What this code represents

The official display label for ICD-10-CM code G81.10 is spastic hemiplegia affecting unspecified side. This diagnostic code is listed alongside more specific variants that identify right dominant, left dominant, right nondominant, and left nondominant sides. 3

Coding details

Code G81.10 for spastic hemiplegia affecting an unspecified side is listed within the same coding framework as G81.11 through G81.14, which specify dominant and nondominant sides. The code G81.90 is also listed for hemiplegia, unspecified affecting an unspecified side. 3

A phecode mapping resource lists the description for spastic hemiplegia affecting an unspecified side alongside descriptions for spastic hemiplegia affecting right dominant, left dominant, right nondominant, and left nondominant sides. This resource also lists flaccid hemiplegia affecting an unspecified side. 4

Documentation considerations

Clinical literature on spastic hemiplegia following stroke evaluates prognostic factors including the side of hemiplegia, designated as left or right, and the stroke type, designated as ischemic or hemorrhagic. These factors were explored in the context of contralateral seventh cervical nerve transfer surgery. 1

Coverage and utilization context

A Medicare billing and coding article for botulinum toxin injections references specific codes for spastic hemiplegia affecting the right dominant side and the left dominant side. The provided excerpt does not establish a coverage determination for the unspecified G81.10 code. 5

What the sources add

While the clinical literature details spastic hemiplegia as a central nervous system sequela involving muscle overactivity, the coding sources establish the specific alphanumeric labels used to classify this condition. The coding sources list G81.10 as an unspecified side diagnosis, whereas the clinical literature identifies left and right side of hemiplegia as patient factors. 1 2 3

The Texas Health and Human Services source and the Medicare billing article both list codes for spastic hemiplegia affecting right dominant and left dominant sides. The Medicare article specifically includes these codes within a botulinum toxin injection billing context, whereas the Texas source provides a broader list of approved diagnostic codes. 3 5

Sources

1. Analysis of factors affecting the efficacy of contralateral seventh cervical nerve transfer for central upper limb paralysis and prediction model for efficacy evaluation — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-25.
3. Approved Diagnostic Codes for Persons with Related ... — hhs.texas.gov; accessed 2026-07-25.
4. Phecode 342 · ExPRSweb — csg.sph.umich.edu; accessed 2026-07-25.
5. Article - Billing and Coding: Botulinum Toxin Injections (A57185) — cms.gov; accessed 2026-07-25.