G43.409
BillableHemiplegic migraine, not intractable, without status migrainosus
HCC Category Mapping
RxHCCHCC 166 — Migraine
0.000What This Code Means
A rare type of migraine causing temporary weakness on one side of the body that responds to treatment and is not in a prolonged migraine state.
Coding Tips
- •Document the specific neurological deficits (weakness location and duration) clearly
- •Hemiplegic migraine requires exclusion of other serious conditions like stroke
Clinical Significance
Hemiplegic migraine is a rare and serious migraine subtype characterized by temporary motor weakness or paralysis on one side of the body, mimicking stroke presentation. Accurate coding is critical because hemiplegic migraine requires distinct management protocols and may indicate increased cerebrovascular risk. This code maps to RxHCC 166 (Severe Head Injury) in the prescription drug risk adjustment model, impacting pharmacy cost predictions.
Documentation Requirements
- ✓Documented unilateral motor weakness or hemiplegia during migraine episode
- ✓Neurological examination findings differentiating from stroke (reversibility, associated aura symptoms)
- ✓Characterization as not intractable (responsive to treatment) vs. intractable
- ✓Documentation of episode duration (status migrainosus = >72 hours; absence should be clear)
- ✓Family history of hemiplegic migraine if applicable (familial vs. sporadic subtype)
- ✓Neuroimaging results (CT/MRI) to exclude cerebrovascular accident
- ✓Current treatment plan and medication regimen
Commonly Confused Codes
G43.001-G43.019 (Migraine without aura) — lacks the motor weakness/hemiplegia component that defines hemiplegic migraineG43.101-G43.119 (Migraine with aura) — has sensory/visual aura but NOT motor weakness; hemiplegic migraine specifically requires motor involvementI63.x (Cerebral infarction) — hemiplegic migraine mimics stroke but is reversible; requires imaging to differentiateG43.601-G43.619 (Persistent migraine aura with cerebral infarction) — use when migraine aura symptoms persist AND imaging confirms infarctionG81.x (Hemiplegia/hemiparesis) — sequela codes for established paralysis, not episodic migraine-related weakness
Code Hierarchy
└G43Migraine└G43.4Hemiplegic migraine└G43.40Hemiplegic migraine, not intractable└G43.409Hemiplegic migraine, not intractable, without status migrainosus
└G43.409Hemiplegic migraine, not intractable, without status migrainosus