G43

Migraine

Migraine is a chronic neurological disorder characterized by recurrent episodes of moderate-to-severe headache that are typically unilateral, pulsating, and aggravated by routine physical activity. The pathophysiology is complex, involving the activation of the trigeminovascular system, the release of calcitonin gene-related peptide (CGRP), and cortical spreading depression (CSD), which is believed to cause the migraine aura. Migraine is more than just a headache; it is a systemic condition often preceded by a prodromal phase (premonitory symptoms like yawning or neck stiffness) and followed by a postdrome (the "migraine hangover"). It affects approximately 12% of the population, with a significantly higher prevalence in women due to hormonal influences. Classification is primarily divided between migraine without aura and migraine with aura, though several subtypes and migraine-associated periodic syndromes exist. Management involves both acute abortive treatments (triptans, NSAIDs, gepants) and preventive strategies (beta-blockers, CGRP monoclonal antibodies, anticonvulsants).

Clinical Symptoms

  • Unilateral, throbbing, or pulsating headache
  • Nausea and vomiting
  • Photophobia (light sensitivity)
  • Phonophobia (sound sensitivity)
  • Osmophobia (odor sensitivity)
  • Visual aura (scotomas, flashing lights, or zigzag lines)
  • Sensory aura (paresthesias or tingling)
  • Speech or language disturbances (dysphasic aura)
  • Neck stiffness and pain
  • Fatigue and irritability
  • Cognitive fog or difficulty concentrating
  • Dizziness or vertigo
  • Prodromal yawning and food cravings

Common Causes

  • Genetic predisposition (polygenic inheritance)
  • Activation of the trigeminovascular system
  • Release of vasoactive neuropeptides like CGRP and substance P
  • Cortical spreading depression (CSD)
  • Hormonal fluctuations (especially estrogen withdrawal in menstrual migraine)
  • Sleep disturbances (insomnia or oversleeping)
  • Stress and emotional triggers
  • Dietary triggers (nitrates, MSG, tyramine, or aged cheeses)
  • Environmental factors (bright lights, weather changes, strong odors)
  • Caffeine overuse or withdrawal

Documentation & Coding Tips

Explicitly state the presence or absence of aura to determine the 4th character specificity.

Example: Patient presents for follow-up of recurring headaches. She describes a 15-minute visual prodrome consisting of shimmering lights and jagged lines followed by a severe throbbing right-sided hemicranial pain. Diagnosis: Migraine with aura, not intractable, without status migrainosus (G43.109). Management includes daily prophylaxis with topiramate and sumatriptan for acute attacks.

Billing Focus: Documentation of aura (visual, sensory, or speech disturbances) is required to distinguish G43.1 (with aura) from G43.0 (without aura).

Define intractability based on the patient's response to multiple medication classes.

Example: Assessment: Chronic migraine without aura. Patient has failed three different classes of prophylactic agents (Beta-blockers, TCAs, and Antiepileptics) and continues to experience 18 headache days per month. The condition is documented as intractable (G43.719) for coding purposes.

Billing Focus: The term intractable must be explicitly used by the provider to assign the corresponding character (e.g., G43.x1x). Synonyms like pharmacoresistant or refractory are acceptable clinically but must map to intractable.

Distinguish between episodic migraine and chronic migraine based on the frequency of attacks.

Example: Patient reports a total of 17 headache days per month over the last quarter, with at least 9 of those days meeting full criteria for migraine. This meets the clinical threshold for chronic migraine without aura, not intractable, without status migrainosus (G43.709).

Billing Focus: Chronic migraine (G43.7) requires documentation of 15 or more headache days per month for at least 3 months, with migraine features on at least 8 of those days.

Verify the presence of status migrainosus for acute exacerbations lasting longer than 72 hours.

Example: Patient presents to the clinic with a debilitating migraine that has persisted for 96 hours despite home use of naratriptan and ibuprofen. Physical exam shows photophobia and phonophobia. Diagnosed as migraine with aura, not intractable, with status migrainosus (G43.101).

Billing Focus: Status migrainosus is identified by the 6th character (1). Documentation must confirm the headache duration exceeded 72 hours.

Document specific migraine variants such as hemiplegic or ophthalmoplegic for maximum specificity.

Example: Evaluation of 24-year-old male with recurrent attacks of unilateral headache accompanied by reversible motor weakness on the left side. History of similar episodes in father. Diagnosed as familial hemiplegic migraine (G43.409).

Billing Focus: Specific variants (hemiplegic, persistent aura without infarction) map to specific codes in the G43.4, G43.5, and G43.6 ranges.

Relevant CPT Codes

Related Diagnoses

Hierarchy