What is ICD-10 code G43.B0?

G43.B0 is the ICD-10-CM diagnosis code for Ophthalmoplegic migraine, not intractable. A rare type of migraine that causes temporary paralysis of the eye muscles, which can be managed with treatment. It belongs to the ICD-10-CM chapter for diseases of the nervous system (g00-g99). G43.B0 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. G43.B0 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. G43.B0 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. G43.B0 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for G43.B0?

G43.B0 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards G43.B0 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

What should coders know when reporting G43.B0?

Ophthalmoplegic migraine is rare; ensure proper neurological documentation and imaging support the diagnosis This condition may require differentiation from other causes of ophthalmoplegia through diagnostic testing

G43.B0: Ophthalmoplegic migraine, not intractable — ICD-10

ICD-10-CM Code View

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Code lookupG43.B0Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Episodic and paroxysmal disorders (G40-G47)

G43.B0

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Ophthalmoplegic migraine, not intractable

A rare type of migraine that causes temporary paralysis of the eye muscles, which can be managed with treatment.

Buddy Insight

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Not risk-adjusted for this model/period.

RAF 0

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Not risk-adjusted for this model/period.

RAF 0

RXHCC

Mapped

HCC 166

Migraine

RAF 0.0

Code Trumping

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Code Book Path

Official

G43Migraine

G43.BOphthalmoplegic migraine

G43.B0Ophthalmoplegic migraine, not intractable

Inclusion Terms

Official

Ophthalmoplegic migraine, without refractory migraine

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G43.B0 in this effective period.

Related Child Codes

Official

G43.B1Ophthalmoplegic migraine, intractable

Includes

Official

ICD-10-CM does not list Includes notes for G43.B0 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G43.B0 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G43.B0 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G43.B0 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G43.B0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documented ocular cranial nerve palsy (III, IV, or VI nerve involvement specified)

Temporal association between headache and onset of ophthalmoplegia

Recurrent episode pattern (not first-time presentation, which requires urgent workup for other causes)

Neuroimaging results (MRI with gadolinium) excluding structural lesion, aneurysm, or tumor

MEAT Support

HCC Buddy guidance

Documented ocular cranial nerve palsy (III, IV, or VI nerve involvement specified)

Temporal association between headache and onset of ophthalmoplegia

Recurrent episode pattern (not first-time presentation, which requires urgent workup for other causes)

Neuroimaging results (MRI with gadolinium) excluding structural lesion, aneurysm, or tumor

Audit Caution

HCC Buddy guidance

Coding ophthalmoplegic migraine without documented neuroimaging excluding structural lesion — always verify workup is complete

Confusing ophthalmic migraine (visual aura) with ophthalmoplegic migraine (cranial nerve palsy) — very different conditions

Applying this code to first-time ophthalmoplegia with headache, which should be worked up as potential neurological emergency

Not documenting which cranial nerve is affected and the specific eye movement deficit

Common Mistakes

HCC Buddy guidance

H49.00-H49.89 (Paralytic strabismus/cranial nerve palsies) — use for isolated cranial nerve palsy without migraine context

G43.401-G43.419 (Hemiplegic migraine) — involves body hemiparesis, not ocular nerve palsy

G43.801-G43.819 (Other migraine) — ophthalmoplegic migraine has its own specific code; do not use 'other'

I67.1 (Cerebral aneurysm, nonruptured) — must be excluded as cause of third nerve palsy before coding ophthalmoplegic migraine

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is G43.B0 an HCC code?

No. G43.B0 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

HCC Category Mapping

RxHCCHCC 166, Migraine

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work G43.B0 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for G43.B0

For G43.B0to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed G43.B0 during that encounter, not just copy-forwarded from a problem list.

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What This Code Means

G43.B0 is the ICD-10-CM diagnosis code for ophthalmoplegic migraine, not intractable. A rare type of migraine that causes temporary paralysis of the eye muscles, which can be managed with treatment. G43.B0 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering episodic and paroxysmal disorders (g40-g47).

G43.B0 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

Maps to RxHCC 166 (Severe Head Injury) with a RAF weight of 0.000 in the prescription drug model. No mapping to CMS-HCC V28 or V24 payment models. The RxHCC mapping captures pharmacy utilization associated with this rare migraine variant. No hierarchies apply. The clinical significance exceeds the risk adjustment impact.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G43.B0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Ophthalmoplegic migraine is rare; ensure proper neurological documentation and imaging support the diagnosis
•This condition may require differentiation from other causes of ophthalmoplegia through diagnostic testing

Clinical Significance

Ophthalmoplegic migraine (now reclassified as recurrent painful ophthalmoplegic neuropathy) involves recurrent episodes of headache accompanied by paresis of one or more ocular cranial nerves (III, IV, or VI). This rare condition requires thorough neurological workup to exclude aneurysm, tumor, or other compressive lesions, making accurate coding important for justifying diagnostic imaging. The distinction between intractable and not intractable reflects treatment responsiveness and impacts medication management decisions.

Documentation Requirements

✓Documented ocular cranial nerve palsy (III, IV, or VI nerve involvement specified)
✓Temporal association between headache and onset of ophthalmoplegia
✓Recurrent episode pattern (not first-time presentation, which requires urgent workup for other causes)
✓Neuroimaging results (MRI with gadolinium) excluding structural lesion, aneurysm, or tumor
✓Resolution of ophthalmoplegia between episodes (though residual deficit may persist)
✓Treatment response noted
✓Ophthalmologic examination documenting specific eye movement deficits

Commonly Confused Codes

•H49.00-H49.89 (Paralytic strabismus/cranial nerve palsies): use for isolated cranial nerve palsy without migraine context
•G43.401-G43.419 (Hemiplegic migraine): involves body hemiparesis, not ocular nerve palsy
•G43.801-G43.819 (Other migraine): ophthalmoplegic migraine has its own specific code; do not use 'other'
•I67.1 (Cerebral aneurysm, nonruptured): must be excluded as cause of third nerve palsy before coding ophthalmoplegic migraine
•H46.x (Optic neuritis): inflammation of optic nerve, not ocular motor nerve palsy

Child Codes

G43.B0Ophthalmoplegic migraine, not intractable

G43.B1Ophthalmoplegic migraine, intractable

Code Hierarchy

└G43Migraine └G43.BOphthalmoplegic migraine └G43.B0Ophthalmoplegic migraine, not intractable

└G43.B0Ophthalmoplegic migraine, not intractable

G43.B0 ICD-10-CM Code: Ophthalmoplegic migraine, not intractable

HCC Buddy Code Card

G43.B0

Is G43.B0 an HCC code?

HCC Category Mapping

MEAT Criteria for G43.B0

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What This Code Means

Coding Tips

Clinical Significance

Documentation Requirements

Commonly Confused Codes

Child Codes

Code Hierarchy

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