G80.2

🧬 ICD-10 CM G80.2 — Spastic hemiplegic cerebral palsy

Billable Code Confirmed

ICD-10 CM G80.2 is a valid, billable 4-character ICD-10-CM code for FY2026. No further specificity (such as a 5th or 6th character for laterality) is required or available for this code¹.

Clinical Context: Congenital vs. Acquired Hemiplegia

G80.2 is specifically reserved for spastic hemiplegia that is congenital or stems from an early developmental brain injury (cerebral palsy)³. If a patient develops spastic hemiplegia later in life due to a stroke, trauma, or tumor, you must use a code from the G81.1- family (Spastic hemiplegia) or an I69.- sequelae code instead of G80.2.

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🔍 Code Description

ICD-10 CM G80.2 classifies spastic hemiplegic cerebral palsy, a subtype of cerebral palsy characterized by increased muscle tone (spasticity) and weakness (paresis) or paralysis primarily affecting one side of the body³. The upper extremity is typically more severely affected than the lower extremity.

Cerebral palsy (CP) refers to a group of non-progressive, permanent movement and posture disorders caused by a non-evolving disturbance that occurred in the developing fetal or infant brain. While the brain lesion itself does not progress, the clinical manifestations—such as joint contractures, musculoskeletal deformities, and functional limitations—can worsen over time.

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🌳 Code Tree / Hierarchy

G80 Cerebral palsy ❌ Non-billable Category
 │
 ├── G80.0 Spastic quadriplegic cerebral palsy ✅ Billable
 │
 ├── G80.1 Spastic diplegic cerebral palsy ✅ Billable
 │
 ├── G80.2 Spastic hemiplegic cerebral palsy ◀ THIS CODE ✅ Billable
 │
 ├── G80.3 Athetoid cerebral palsy ✅ Billable
 │
 ├── G80.4 Ataxic cerebral palsy ✅ Billable
 │
 ├── G80.8 Other cerebral palsy ✅ Billable
 │
 └── G80.9 Cerebral palsy, unspecified ✅ Billable

Laterality in Documentation

While the ICD-10 CM G80.2 does not contain characters to distinguish between the left and right sides, the side affected should still be explicitly documented in the clinical note. Medical necessity for targeted treatments (like botulinum toxin injections or physical therapy to a specific limb) relies on detailed laterality in the clinical documentation.

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✅ Includes

The following clinical terminology maps to G80.2 when documented by a provider:

• Congenital spastic hemiplegia

• Hemiplegic cerebral palsy

• Spastic hemiparetic cerebral palsy

• Infantile spastic hemiplegia

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❌ Excludes

Excludes 1 — Cannot Be Coded Simultaneously

The following conditions cannot be coded alongside G80.2 as they represent distinct, overlapping, or mutually exclusive concepts:

Code	Description	Note
G81.10	Spastic hemiplegia affecting unspecified side	Acquired spastic hemiplegia. Excludes 1 note explicitly forbids coding G81.1- alongside G80.2 for congenital cases.
G81.90	Hemiplegia, unspecified	Used for unspecified acquired hemiplegia.
G80.0	Spastic quadriplegic cerebral palsy	Mutually exclusive subtype of CP.

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📋 Clinical Overview

Pathophysiology

Spastic hemiplegic CP is most commonly caused by unilateral brain damage, typically involving the middle cerebral artery (MCA) territory, periventricular leukomalacia, or a focal intracerebral hemorrhage during the perinatal period. The damage to the upper motor neurons in the corticospinal tract leads to a loss of inhibitory signals to the lower motor neurons, resulting in hyperreflexia, hypertonia (spasticity), and weakness on the contralateral side of the body.

Classic Presentation and Manifestations

• Motor Delays: Often recognized in infancy when the child shows early hand preference (before 12-18 months) or asymmetry in crawling and reaching.

• Spasticity: Hypertonia predominantly on one side. The arm is often held in a flexed, pronated posture with a clenched fist; the leg may show equinus deformity (toe walking) and a circumduction gait.

• Associated Conditions: Patients with spastic hemiplegic CP have a high incidence of comorbid conditions that require separate coding, including:

  • Seizure disorders / Epilepsy (approx. 30-40% of cases)

  • Cognitive or learning disabilities

  • Visual impairments (e.g., strabismus, hemianopsia)

  • Joint contractures

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💰 HCC Risk Adjustment (CMS-HCC v28)

Field	Detail
CMS-HCC Model Version	v28 (2024-2026 Implementation)
HCC Assignment	HCC 192
HCC Category	Cerebral Palsy, Except Quadriplegic
RAF Coefficient	Subject to demographic variables

Under the v28 CMS-HCC model, G80.2 maps directly to HCC 192 (Cerebral Palsy, Except Quadriplegic).

Comorbidity Sweep

Patients with CP frequently have conditions that map to other distinct HCC categories. Always sweep the record and assign additional codes for actively managed comorbidities, such as:

• Epilepsy (G40.909 — maps to HCC 201)

• Malnutrition (E44.0 — maps to HCC 47)

• Major depressive disorder (F32.9 — maps to HCC 155)

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🏥 MS-DRG Assignment

MDC 01 — Diseases and Disorders of the Nervous System

DRG	Title
DRG 056	Degenerative Nervous System Disorders with MCC
DRG 057	Degenerative Nervous System Disorders without MCC

Reference: IPPS FY2026 Final Rule MS-DRG Tables.

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🛠️ CPT Procedural Crosswalk

While ICD-10 CM G80.2 is a diagnosis code, it frequently justifies the medical necessity for specific evaluation and management services, physical medicine, and spasticity interventions.

CPT Code	Description	Example Context
99214	E/M established patient, moderate complexity	Routine multi-disciplinary CP clinic follow-up.
64640	Destruction by neurolytic agent; other peripheral nerve or branch	Chemodenervation (Botox) injections into spastic muscles to improve range of motion.
97110	Therapeutic procedure, 1 or more areas, each 15 minutes; therapeutic exercises	Physical therapy to stretch contractures and improve hemiparetic gait.
97161	Physical therapy evaluation: low complexity	Initial baseline functional assessment.

Modifier Usage for Spasticity Injections

When injecting botulinum toxin (e.g., 64640) into multiple separate muscles on the hemiplegic side, specific modifier requirements (like -59 or -RT/-LT) depend heavily on the payer’s policy and whether the nerves injected are considered separate anatomical sites. Also, do not forget to bill the HCPCS J-code for the medication supply (e.g., J0585).

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💊 Coding Scenarios and Examples

Scenario 1 — Outpatient Follow-up with Botulinum Toxin Injection

Clinical Vignette: A 12-year-old male with right-sided spastic hemiplegic cerebral palsy presents to the pediatric neurology clinic for his scheduled botulinum toxin injections. He has severe spasticity in the right gastrocnemius, causing toe-walking. The neurologist performs the injection into the right gastrocnemius under EMG guidance.

CPT:

• 64640 — Destruction by neurolytic agent; peripheral nerve (for the spastic muscle)

• 95874 — Needle electromyography for guidance in conjunction with chemodenervation

• J0585 — Injection, onabotulinumtoxinA (billed per unit)

ICD-10-CM:

• G80.2 — Spastic hemiplegic cerebral palsy (Supports medical necessity for the neurolytic destruction)

• M21.511 — Acquired equinovarus deformity, right foot (Optional but adds specificity to the functional outcome of the CP)

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Scenario 2 — Evaluation for New Onset Seizures

Clinical Vignette: A 16-year-old female with a known history of left spastic hemiplegic CP is brought to the ED after experiencing a generalized tonic-clonic seizure lasting 3 minutes. She has no prior history of epilepsy. She is stabilized, and a neurology consult is requested. An EEG is ordered, and she is started on Keppra.

CPT:

• 99284 — Emergency department visit, moderate/high complexity

ICD-10-CM:

• G40.909 — Epilepsy, unspecified, not intractable, without status epilepticus (Primary reason for the acute encounter)

• G80.2 — Spastic hemiplegic cerebral palsy (Secondary diagnosis; crucial contextual comorbidity that lowers the seizure threshold)

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⚠️ Coding Pitfalls and Tips

	Pitfall or Tip
❌	Do NOT use G81.10 (Spastic hemiplegia) for CP patients. This is a common denial trigger. The Excludes1 note states that congenital spastic hemiplegia must be coded using G80.2.
❌	Do NOT assign “history of” codes for Cerebral Palsy. CP is a lifelong, permanent condition. Even if the patient is highly functional as an adult, it remains an active diagnosis and should be coded as G80.2, not as a “history of” disease.
✅	Look for underlying causes if documented. If the physician documents the exact perinatal cause (e.g., periventricular leukomalacia P91.2), it can be coded additionally to provide a complete clinical picture.
✅	Capture all associated functional deficits. CP rarely exists in a vacuum. Code all documented contractures, gait abnormalities (R26.2), scoliosis (M41.4-), and cognitive deficits, as these paint a true picture of the patient’s severity of illness and risk adjustment.

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📚 Sources

1. CMS/NCHS. ICD-10-CM Official Guidelines for Coding and Reporting, FY2026. Tabular List — G80.2; Excludes 1 logic for G81.- and G80.- family codes.

2. Centers for Medicare & Medicaid Services (CMS). 2024-2026 Advance Notice of Methodological Changes for CMS-HCC Model v28. Mapping of G80.2 to HCC 192 (Cerebral Palsy, Except Quadriplegic).

3. American Academy for Cerebral Palsy and Developmental Medicine (AACPDM). Clinical practice parameters for CP. Pathophysiology, congenital nature, and classification of spastic hemiplegia.

4. CMS. IPPS Final Rule FY2026 — MS-DRG Definitions Manual v43. MDC 01 — Diseases and Disorders of the Nervous System, DRGs 056-057.