G43.B1 ICD-10-CM Code: Ophthalmoplegic migraine, intractable
G43.B1 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Episodic and paroxysmal disorders (G40-G47)
G43.B1
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOphthalmoplegic migraine, intractable
A severe type of migraine that causes temporary paralysis of the eye muscles, making it difficult or impossible to move the eyes, and does not respond well to treatment.
Buddy Insight
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).
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
MappedHCC 166
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Ophthalmoplegic migraine, with refractory migraine
Excludes 2
Official- certain conditions originating in the perinatal period (P04-P96)Inherited from G00-G99, G43
- certain infectious and parasitic diseases (A00-B99)Inherited from G00-G99, G43
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from G00-G99, G43
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from G00-G99, G43
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from G00-G99, G43
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from G00-G99, G43
- neoplasms (C00-D49)Inherited from G00-G99, G43
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from G00-G99, G43
- headache NOS (R51.9)Inherited from G00-G99, G43
- headache syndromes (G44.-)Inherited from G00-G99, G43
Related Codes
Includes
OfficialNo Includes notes are included in this display for G43.B1. Check the code and parent instructions in the Code Book.
Excludes 1
Official- lower half migraine (G44.00)Inherited from G43
Code First
OfficialNo Code First sequencing instructions are included in this display for G43.B1. Check the code and parent instructions in the Code Book.
Use Additional
Official- code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)Inherited from G43
Code Also
OfficialNo Code Also instructions are included in this display for G43.B1. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is G43.B1 an HCC code?
G43.B1 has no mapping under the current CMS-HCC V28 community payment model. G43.B1 has a separate mapping under the Part D RxHCC model (HCC 166 (Migraine Headaches)); the applicable result needs member context.
- Code
- G43.B1
- Description
- Ophthalmoplegic migraine, intractable
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work G43.B1 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for G43.B1
For G43.B1, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
Get the V28 mapping + MEAT cheat sheet
One printable reference: check representative V28 mappings and the documentation reminders your note needs. Free, no card.
Free PDF. No card. Unsubscribe anytime.
What This Code Means
G43.B1 is the ICD-10-CM diagnosis code for ophthalmoplegic migraine, intractable. A severe type of migraine that causes temporary paralysis of the eye muscles, making it difficult or impossible to move the eyes, and does not respond well to treatment. G43.B1 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.B1 has no mapping under the current CMS-HCC V28 community payment model. G43.B1 has a separate mapping under the Part D RxHCC model (HCC 166 (Migraine Headaches)); the applicable result needs member context. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.
Verify documentation confirms both ophthalmoplegic features and intractability (resistant to treatment).
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for G43.B1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation confirms both ophthalmoplegic features and intractability (resistant to treatment)
- •This is a rare migraine variant; ensure proper differentiation from other neurological conditions causing eye movement problems
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)
- ✓Intractability status documented
- ✓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