Abstract
Although Acute Confusional Migraine (ACM) is not currently included in the International Classification of Headache Disorders, 3rd edition (ICHD-3β), it is a well-recognized migraine variant that merits formal classification. ACM is a disabling condition characterized by a distinct clinical presentation, and it may also involve unique underlying mechanisms and treatment considerations. Its exclusion from official classification systems increases the risk of misdiagnosis, overuse of emergency services and may hinder appropriate clinical management.
Originally described in 1978 by Ehyai et al. (1), it was later published in the journal Cephalalgia (2). ACM typically presents with an acute episode of confusion, disorientation, agitation, altered awareness and/or short-term memory impairment, occurring in temporal relation to a migraine attack (1). While most frequently reported in children and adolescents, adult cases have also been documented. In a 2018 systematic review, Farooqi et al. (3) compiled 120 cases from the literature and proposed preliminary diagnostic criteria, emphasizing the need for a formal classification framework to guide diagnosis, treatment and research.
The syndrome of ACM is frequently mistaken for more serious neurological conditions such as epilepsy, stroke or encephalitis. This misdiagnosis often leads to unnecessary and potentially invasive diagnostic procedures and treatments, including computed tomography (CT) scans, brain magnetic resonance imaging (MRI), angiography, lumbar puncture, thrombolysis or the use of anticonvulsants. Such missteps can contribute to increased patient morbidity, higher healthcare costs and added stress for clinicians.
Pathophysiological considerations
The cortical spreading depolarization model, already well established in migraine with aura, may explain many of the cognitive and neurobehavioral features of ACM (4). Spreading cortical dysfunction, particularly involving the frontal and limbic cortices, could account for symptoms such as inattention, disorientation, and speech or memory disturbances.
Moreover, ictal electroencephalographic abnormalities have been observed in several cases, most notably frontal intermittent rhythmic delta activity or generalized slowing, which typically resolve within one week (2) Although not pathognomonic, these findings may support the appropriate diagnosis in ambiguous diagnosis, clinical presentations, helping distinguish ACM from epileptic phenomena, especially in adolescents. Neuroimaging during ACM episodes is consistently normal, reinforcing its functional and reversible nature.
Interestingly, similar episodes of altered consciousness and encephalopathy have been reported in patients with familial hemiplegic migraine and CADASIL (i.e. involving cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (5,6). This intersection of migraine biology, genetics and cortical excitability reinforces the plausibility of ACM as a migraine-driven phenomenon.
Clinical and diagnostic implications
Given the reported cases and shared biological underpinnings with other migraine subtypes, we propose the inclusion of ACM in the appendix of the forthcoming International Classification of Headache Disorders, 4th edition (ICHD-4) (7), under section A1.6 (Episodic syndromes that may be associated with migraine).
Table 1 summarizes the original diagnostic criteria for ACM proposed by Farooqi et al. (3) alongside our updated version. The revised criteria aim to improve diagnostic clarity and clinical applicability.
Diagnostic criteria for acute confusional migraine: proposed for International Classification of Headache Disorders, 4th edition (ICHD-4).
CT = computed tomagraphy; EEG = electroencephalogram; MRI = magnetic resonance imaging.
We specifically propose the following considerations:
Replacing “agitation or combative behavior” with more specific features such as short-duration (for less than one hour) aura or electroencephalogram (EEG) slowing. Requiring normal brain imaging (brain CT scan with perfusion or MRI) in addition to a normal neurological examination to help differentiate from other neurological diseases. Allowing disorientation or decreased attention to fulfill the cognitive requirement rather than narrowly defined “impaired executive function”.
This updated framework improves feasibility, making a diagnosis practical in real-world clinical settings, thereby enhancing the utility of the criteria in clinical practice and research settings.
Conclusions and recommendation
Inclusion of ACM in the ICHD-4 appendix (7) would reflect emerging evidence, reduce misdiagnosis, guide clinical management and stimulate further investigation. Recognizing ACM as an episodic migraine syndrome, similar to abdominal migraine or cyclical vomiting, will increase diagnostic confidence and therapeutic precision.
We respectfully encourage the International Headache Society Classification Committee to consider this proposal for the upcoming revision of the ICHD and would welcome the opportunity to contribute to the development of consensus criteria and validation studies.
Footnotes
Author contributions
Karen S. Ferreira: Design, Discussion, Writing the paper, Final approval. Ana Miriam Velly: Design, Discussion, Writing the paper, Final approval.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.
Funding
The authors received no financial support for the research, authorship and/or publication of this article.
Data availability
The authors declare that data supporting the findings of this study are available within the article.
