ICD-10-CM > R00-R99 > R50-R69 > R51 R51 Headache Non-Billable/Non-Specific Type 2 Excludes atypical face pain (G50.1)migraine and other headache syndromes (G43-G44)trigeminal neuralgia (G50.0) Codes R51.0Headache with orthostatic component, not elsewhere classifiedR51.9Headache, unspecified