2008 ICD-9-CM Volume 1 Diagnosis Codes Home > Diseases Of The Nervous System And Sense Organs 320-389 > Other Disorders Of The Central Nervous System 340-349 > 2008 ICD-9-CM Diagnosis 346 Migraine  On October 1, 2008 the 2009 ICD-9-CM codes came into effect. Therefore, this code may be out of date. The 2009 version of ICD-9-CM 346 can be accessed here. A subtype of vascular headaches characterized by periodic unilateral pulsatile headaches which begin in childhood, adolescence, or early adult life and recur with diminishing frequency during advancing years. The two major subtypes are CLASSIC MIGRAINE (i.e., migraine with aura) and COMMON MIGRAINE (i.e., migraine without aura). Migrainous episodes may be associated with alterations in cerebral blood flow. (From Adams et al., Principles of Neurology, 6th ed, p172) 346 is a non-specific code that cannot be used to specify a diagnosis ICD9Data's sister site ProcedureCodes.com launches with the 2008/09 CPT® codes - read more on the ICD9Data.com blog.