Acute confusional migraine: our knowledge to date.

Acute confusional migraine (ACM) is a rare migraine variant, affecting children and adolescents, as well as adults. Between 0.45 and 7.8% of children with migraine present with ACM, but the disorder may well be underdiagnosed. ACM is an exclusion diagnosis and some dangerous causes of confusion (e.g., epilepsy, ischemia, hemorrhagia, neoplasm, intoxication and encephalitis) should be ruled out. The confusional state often manifests with a wide diversity of cortical dysfunctions, such as speech difficulties, increased alertness, agitation and amnesia. Exact history taking, clinical examination, and laboratory, radiological and electroencephalographical findings lead the practitioner towards the diagnosis. Approximately half of the cases may be triggered by mild head trauma. Transient global amnesia is an important differential diagnosis, possibly caused by similar pathophysiological mechanisms. The exact pathomechanism remains unclear, with the common hypothesis comprising of the confusional state as a complex aura phenomenon, in which the cortical spreading depression wave reaches not only the occipital, but also the temporal, parietal and frontal cortex, as well as the brainstem and the hippocampi, leading to transient hypoperfusion and dysfunction of these brain areas.