|Coded elsewhere||Migraine-like headache secondary to another disorder (symptomatic migraine) is coded according to the disorder.|
Primary or secondary headache or both?
When a headache with migraine characteristics occurs for the first time in close temporal relation to another disorder that is a known cause of headache, it is coded according to the causative disorder as a secondary headache. When pre-existing migraine is made worse in close temporal relation to another disorder that is a known cause of headache, there are two possibilities, and judgment is required. The patient can either be given only the migraine diagnosis or be given both the migraine diagnosis and a secondary headache diagnosis according to the other disorder. Factors that support adding the latter diagnosis are: a very close temporal relation to the disorder, a marked worsening of the migraine, very good evidence that the disorder can cause or aggravate migraine, and improvement or resolution of migraine after relief from the disorder.
Migraine is a common disabling primary headache disorder. Epidemiological studies have documented its high prevalence and high socio-economic and personal impacts. It is now ranked by the World Health Organization as number 19 among all diseases world-wide causing disability.
Migraine can be divided into two major sub-types. 1.1 Migraine without aura is a clinical syndrome characterised by headache with specific features and associated symptoms. 1.2 Migraine with aura is primarily characterised by the focal neurological symptoms that usually precede or sometimes accompany the headache. Some patients also experience a premonitory phase, occurring hours or days before the headache, and a headache resolution phase. Premonitory and resolution symptoms include hyperactivity, hypoactivity, depression, craving for particular foods, repetitive yawning and other less typical symptoms reported by some patients.
When a patient fulfils criteria for more than one subtype of migraine, all subtypes should be diagnosed and coded. For example, a patient who has frequent attacks with aura but also some attacks without aura should be coded as 1.2 Migraine with aura and 1.1 Migraine without aura.