Changes in Migraine Symptoms after Ischemic Stroke: A Cohort Study.

INTRODUCTION: Migraine symptoms are postulated to improve post-stroke. We aimed to determine post-stroke changes in patients with active migraine pre-stroke and explored the relation with stroke location and stroke-preventive medication use. METHODS: Patients with active migraine who had an ischemic stroke were retrieved from three research-cohorts between 2014 and 2021. By an interview, we retrospectively investigated first-year post-stroke changes for those ischemic stroke patients that suffered from migraine pre-stroke. Associations between change in migraine frequency/intensity/aura (decrease, no change, increase), stroke location (posterior location vs. other), and use of secondary stroke preventive medication were assessed by ordinal regression with adjustment for confounders. RESULTS: We included 78 patients (mean age 48 years, 86% women, 47% with aura). Change in migraine symptomatology was reported by 63 (81%) patients; 51 (81%) noticed a decrease in attack frequency (27 no attacks) and 12 (19%) an increase. Pain intensity change was reported by 18 (35%) patients (50% increase, 50% decrease). Aura symptomatology improved in 4 (11%). Reduced attack frequency was not related to posterior stroke (OR = 1.5, 95% CI: 0.6-3.9), or preventive medication (antiplatelets OR = 1.0, 95% CI: 0.2-3.7; coumarin OR = 2.7, 95% CI: 0.4-20.6). CONCLUSIONS: Most patients with active pre-stroke migraine experience improvement of their symptoms in the first year after ischemic stroke. This change does not seem to be related to secondary stroke preventive medication or posterior stroke location.

Neurological and psychiatric comorbidities of migraine: Concepts and future perspectives.

BACKGROUND: This narrative review aims to discuss several common neurological and psychiatric disorders that show comorbidity with migraine. Not only can we gain pathophysiological insights by studying these disorders, comorbidities also have important implications for treating migraine patients in clinical practice. METHODS: A literature search on PubMed and Embase was conducted with the keywords "comorbidity", "migraine disorders", "migraine with aura", "migraine without aura", "depression", "depressive disorders", "epilepsy", "stroke", "patent foramen ovale", "sleep wake disorders", "restless legs syndrome", "genetics", "therapeutics". RESULTS: Several common neurological and psychiatric disorders show comorbidity with migraine. Major depression and migraine show bidirectional causality and have shared genetic factors. Dysregulation of both hypothalamic and thalamic pathways have been implicated as a possibly cause. The increased risk of ischaemic stroke in migraine likely involves spreading depolarizations. Epilepsy is not only bidirectionally related to migraine, but is also co-occurring in monogenic migraine syndromes. Neuronal hyperexcitability is an important overlapping mechanism between these conditions. Hypothalamic dysfunction is suggested as the underlying mechanism for comorbidity between sleep disorders and migraine and might explain altered circadian timing in migraine. CONCLUSION: These comorbid conditions in migraine with distinct pathophysiological mechanisms have important implications for best treatment choices and may provide clues for future approaches.

Spectral Domain Optical Coherence Tomography in Retinal Vasculopathy With Cerebral Leukoencephalopathy and Systemic Manifestations: A Monogenic Small Vessel Disease.

BACKGROUND: Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is a monogenic small vessel disease caused by mutations in TREX1. Several organs, including retina and brain, are affected. Analyzing retinal anatomy is increasingly used as a biomarker for ophthalmological and neurological disorders (due to the shared embryological origin of retina and brain). Optical coherence tomography (OCT) provides a noninvasive cross-sectional visualization of optic disc and macula. We aimed to use OCT to investigate retinal layer thickness in RVCL-S. METHODS: Cross-sectional, 17 TREX1 mutation carriers (34 eyes) and 9 controls (18 eyes) underwent comprehensive ophthalmologic assessment followed by spectral domain OCT for measuring peripapillary retinal nerve fiber layer (pRNFL) thickness and total macular volume (TMV). Secondary outcomes included measuring thickness of individual macular retinal layers and peripapillary sectors. Findings were analyzed using generalized estimating equations to account for intereye correlation. RESULTS: TREX1 mutation carriers had decreased pRNFL thickness (median [interquartile range] 76 [60-99] vs 99 [87-108] µm, P < 0.001) and TMV (8.1 [7.4-8.5] vs 8.7 [8.4-8.8] mm3, P = 0.006) compared with controls. With the exception of the temporal sector, the thickness of all peripapillary sectors was decreased in TREX1 mutation carriers. Ganglion cell layer (30 [22-37] vs 39 [36-41] µm, P < 0.001) and inner plexiform layer (27 [24-34] vs 34 [31-35], P = 0.001) were thinner in TREX1 mutation carriers. Notably, in 9 of 12 eyes with normal funduscopic examination, retinal thinning was already detected. CONCLUSIONS: RVCL-S, which may serve as a vascular retinopathy model, is associated with retinal thinning in the peripapillary and macular area. OCT findings can potentially serve as early biomarkers for RVCL-S and other vascular retinopathies.

The effect of needle size on cerebrospinal fluid collection time and post-dural puncture headache: A retrospective cohort study.

OBJECTIVE: The main objective of this study was to compare cerebrospinal fluid (CSF) collection time and patient's discomfort between 20G (a)traumatic and 22G atraumatic needles. BACKGROUND: Risk of post-dural puncture headache (PDPH) is decreased using atraumatic needles. Smaller needles may give lower risk but possibly at the cost of increased CSF collection time (due to lower flow), leading to additional patient's discomfort. METHODS: We performed a retrospective study of lumbar puncture data from a research program on CSF metabolomics and compared traumatic 20G (n = 210) with atraumatic 20G (n = 39) and 22G (n = 105) needles. In this cohort, incidence of PDPH was prospectively registered with other procedure details. Primary outcome was CSF collection time (time to fill the tube). Secondary outcomes were pain and stress scores during procedure, and incidence of PDPH. RESULTS: The time to collect 10 mL of CSF was longer for 22G needles (6.1 minutes; 95% CI 5.8-6.5) than for 20G traumatic (2.2 minutes; 95% CI 2.1-2.2) and 20G atraumatic needles (2.9 minutes; 95% CI 2.8-3.1). There were no differences in pain and stress scores. PDPH was lower for 22G atraumatic needles: odds ratio 0.41 (95% CI 0.25-0.66) versus 20G traumatic needles and 0.53 (95% CI 0.40-0.69) versus 20G atraumatic needles. Absolute PDPH rates were 69/210 (32.9%) for 20G traumatic, 13/39 (33.3%) for 20G atraumatic, and 19/105 (18.1%) for 22G atraumatic needles. CONCLUSIONS: CSF collection time is slightly longer for smaller 22G needles, but this does not lead to more discomfort for the patient.

Linking migraine frequency with family history of migraine.

BACKGROUND: Migraine is a complex genetic disorder that is brought about by multiple genetic and environmental factors. We aimed to assess whether migraine frequency is associated with genetic susceptibility. METHODS: We investigated in 2829 migraine patients (14% males) whether 'migraine frequency' (measured as the number of migraine days per month) was related to 'genetic load' (measured as the number of parents affected with migraine) using a validated web-based questionnaire. In addition, we investigated associations with age-at-onset, migraine subtype, use of acute headache medication, and comorbid depression. RESULTS: We found an association between the number of migraine days per month and family history of migraine for males ( p = 0.03), but not for females ( p = 0.97). This association was confirmed in a linear regression analysis. Also, a lower age-at-onset ( p < 0.001), having migraine with aura ( p = 0.03), and a high number of medication days ( p = 0.006) were associated with a stronger family history of migraine, whereas lifetime depression ( p = 0.13) was not. DISCUSSION: Migraine frequency, as measured by the number of migraine days per month, seems associated with a genetic predisposition only in males. A stronger family history of migraine was also associated with a lower age-at-onset, a higher number of medication days, and migraine with aura. Our findings suggest that specific clinical features of migraine seem more determined by genetic factors.

Brain atrophy following hemiplegic migraine attacks.

Background Patients with hemiplegic migraine (HM) may sometimes develop progressive neurological deterioration of which the pathophysiology is unknown. Patient We report a 16-year clinical and neuroradiological follow-up of a patient carrying a de novo p.Ser218Leu CACNA1A HM mutation who had nine severe HM attacks associated with seizures and decreased consciousness between the ages of 3 and 12 years. Results Repeated ictal and postictal neuroimaging revealed cytotoxic oedema during severe HM attacks in the symptomatic hemisphere, which later showed atrophic changes. In addition, progressive cerebellar atrophy was observed. Brain atrophy halted after cessation of severe attacks, possibly due to prophylactic treatment with flunarizine and sodium valproate. Conclusion Severe HM attacks may result in brain atrophy and prophylactic treatment of these attacks might be needed in an early stage of disease to prevent permanent brain damage.

Circulating Endothelial Markers in Retinal Vasculopathy With Cerebral Leukoencephalopathy and Systemic Manifestations.

BACKGROUND AND PURPOSE: Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is a monogenic small vessel disease, caused by C-terminal truncating TREX1 mutations, that can be considered a model for stroke and vascular dementia. The pathophysiology of RVCL-S is largely unknown, but systemic endothelial involvement has been suggested, leading to pathology in the brain and other highly vascularized organs. Here, we investigated circulating endothelial markers to confirm endothelial involvement and identify biomarkers for disease activity. METHODS: We measured circulating levels of von Willebrand factor (VWF) antigen, VWF propeptide, and angiopoietin-2 in members of 3 Dutch RVCL-S families and matched unrelated healthy controls. Stratified analyses based on symptomatology and age were performed. RESULTS: We found elevated levels of VWF antigen, VWF propeptide, and angiopoietin-2 in TREX1 mutation carriers (n=31) compared with family members without a TREX1 mutation (n=33) and unrelated healthy controls (n=31; Kruskal-Wallis test P<0.001 for all comparisons). Effects were most pronounced in mutation carriers with clinical manifestations aged ≥40 years (Mann-Whitney U test P<0.001 for all comparisons). Compared with healthy controls, levels of VWF antigen (P=0.02) and angiopoietin-2 (P=0.04) were also elevated in mutation carriers aged <40 years. All 3 markers showed moderate correlations with markers of kidney and liver disease and inflammation (ie, systemic symptoms of RVCL-S). CONCLUSIONS: Our results confirm an important role of the endothelium in RVCL-S pathophysiology. VWF antigen, VWF propeptide, and angiopoietin-2 might serve as early biomarkers of disease activity. Our findings might also help to understand the pathophysiology of common neurovascular disorders, such as stroke.

Assessment of Migraine History in Patients with a Transient Ischemic Attack or Stroke; Validation of a Migraine Screener for Stroke.

BACKGROUND: To investigate the connection between migraine and stroke, a reliable screening tool to gather information about a person's migraine history is crucial. We studied the test-characteristics of a 5-question Migraine Screener for Stroke (MISS). METHODS: We included a random sample of patients with a transient ischemic attack or stroke who answered the MISS questionnaire when they were admitted to our hospital. After discharge, a semi-structured telephone interview was conducted to validate the migraine diagnosis with the International Classification of Headache Disorders, second-edition criteria as gold standard. RESULTS: Forty-nine (22.2%) of the 221 included patients were diagnosed with life-time migraine (38.5% women, 7.7% men). The sensitivity of all questions combined was 0.47 (95% CI 0.31-0.62), the specificity was 0.97 (95% CI 0.93-0.99), the positive predictive value (PPV) was 0.80 (95% CI 0.59-0.93) and the negative predictive value (NPV) was 0.87 (95% CI 0.82-0.92). One question related to the presence of headache accompanied by hypersensitivity to lights and sounds had a better sensitivity (0.96, 95% CI 0.85-1.00) and NPV (0.99, 95% CI 0.95-1.00) than all questions put together. For assessing migraine with aura, the question about visual disturbances had a good NPV (0.99, 95% CI 0.96-1.00), but a low PPV (0.38, 95% CI 0.24-0.53). CONCLUSIONS: The MISS questionnaire can be used by researchers to rule out migraine history in stroke patients. To prevent misclassification, especially for the aura symptoms, patients with a positive screener should be interviewed more extensively to confirm the migraine diagnosis.

Familial hemiplegic migraine treated by sodium valproate and lamotrigine.

BACKGROUND: Familial hemiplegic migraine (FHM) is a rare monogenic subtype of migraine with aura that includes motor auras. Prophylactic treatment of FHM often has marginal effects and involves a trial-and-error strategy based on therapeutic guidelines for non-hemiplegic migraine and on case reports in FHM. METHODS: We assessed the response to prophylactic medication in an FHM family and sequenced the FHM2 ATP1A2 gene in all available relatives. RESULTS: A novel p.Met731Val ATP1A2 mutation was identified. Attack frequency was reduced significantly with sodium valproate monotherapy (n = 1) and attacks ceased completely with a combination of sodium valproate and lamotrigine (n = 2). CONCLUSIONS: We report dramatic prophylactic effects of sodium valproate and lamotrigine in an FHM2 family, making these drugs worth considering in the treatment of other FHM patients.

Two novel SCN1A mutations identified in families with familial hemiplegic migraine.

BACKGROUND: Familial hemiplegic migraine (FHM) is a rare monogenic subtype of migraine with aura, characterized by motor auras. The majority of FHM families have mutations in the CACNA1A and ATP1A2 genes; less than 5% of FHM families are explained by mutations in the SCN1A gene. Here we screened two Spanish FHM families for mutations in the FHM genes. METHODS: We assessed the clinical features of both FHM families and performed direct sequencing of all coding exons (and adjacent sequences) of the CACNA1A, ATP1A2, PRRT2 and SCN1A genes. RESULTS: FHM patients in both families had pure hemiplegic migraine with highly variable severity and frequency of attacks. We identified a novel SCN1A missense mutation p.Ile1498Met in all three tested hemiplegic migraine patients of one family. In the other family, novel SCN1A missense mutation p.Phe1661Leu was identified in six out of eight tested hemiplegic migraine patients. Both mutations affect amino acid residues that either reside in an important functional domain (in the case of Ile(1498)) or are known to be important for kinetic properties of the NaV1.1 channel (in the case of Phe(1661)). CONCLUSIONS: We identified two mutations in families with FHM. SCN1A mutations are an infrequent but important cause of FHM. Genetic testing is indicated in families when no mutations are found in other FHM genes.

Whole Exome Sequencing of Hemiplegic Migraine Patients Shows an Increased Burden of Missense Variants in CACNA1H and CACNA1I Genes.

Hemiplegic migraine (HM) is a rare subtype of migraine with aura. Given that causal missense mutations in the voltage-gated calcium channel α1A subunit gene CACNA1A have been identified in a subset of HM patients, we investigated whether HM patients without a mutation have an increased burden of such variants in the "CACNA1x gene family". Whole exome sequencing data of an Australian cohort of unrelated HM patients (n = 184), along with public data from gnomAD, as controls, was used to assess the burden of missense variants in CACNA1x genes. We performed both a variant and a subject burden test. We found a significant burden for the number of variants in CACNA1E (p = 1.3 × 10-4), CACNA1H (p < 2.2 × 10-16) and CACNA1I (p < 2.2 × 10-16). There was also a significant burden of subjects with missense variants in CACNA1E (p = 6.2 × 10-3), CACNA1H (p < 2.2 × 10-16) and CACNA1I (p < 2.2 × 10-16). Both the number of variants and number of subjects were replicated for CACNA1H (p = 3.5 × 10-8; p = 0.012) and CACNA1I (p = 0.019, p = 0.044), respectively, in a Dutch clinical HM cohort (n = 32), albeit that CACNA1I did not remain significant after multiple testing correction. Our data suggest that HM, in the absence of a single causal mutation, is a complex trait, in which an increased burden of missense variants in CACNA1H and CACNA1I may contribute to the risk of disease.

Genome-wide analysis of 102,084 migraine cases identifies 123 risk loci and subtype-specific risk alleles.

Migraine affects over a billion individuals worldwide but its genetic underpinning remains largely unknown. Here, we performed a genome-wide association study of 102,084 migraine cases and 771,257 controls and identified 123 loci, of which 86 are previously unknown. These loci provide an opportunity to evaluate shared and distinct genetic components in the two main migraine subtypes: migraine with aura and migraine without aura. Stratification of the risk loci using 29,679 cases with subtype information indicated three risk variants that seem specific for migraine with aura (in HMOX2, CACNA1A and MPPED2), two that seem specific for migraine without aura (near SPINK2 and near FECH) and nine that increase susceptibility for migraine regardless of subtype. The new risk loci include genes encoding recent migraine-specific drug targets, namely calcitonin gene-related peptide (CALCA/CALCB) and serotonin 1F receptor (HTR1F). Overall, genomic annotations among migraine-associated variants were enriched in both vascular and central nervous system tissue/cell types, supporting unequivocally that neurovascular mechanisms underlie migraine pathophysiology.

Cerebrovascular reactivity in retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations.

Retinal Vasculopathy with Cerebral Leukoencephalopathy and Systemic manifestations (RVCL-S) is a small vessel disease caused by TREX1 mutations. RVCL-S is characterized by retinal vasculopathy and brain white matter lesions with and without contrast enhancement. We aimed to investigate cerebrovascular reactivity (CVR) in RVCL-S. In this cross-sectional observational study, 21 RVCL-S patients, 23 mutation-negative family members, and 31 healthy unrelated controls were included. CVR to a hypercapnic challenge was measured using dual-echo arterial spin labeling magnetic resonance imaging. Stratified analyses based on age were performed. We found that CVR was decreased in gray and white matter of RVCL-S patients compared with family members and healthy controls (ANCOVA; P < 0.05 for all comparisons). This was most noticeable in RVCL-S patients aged ≥40 years (ANCOVA, P < 0.05 for all comparisons). In RVCL-S patients aged < 40 years, only CVR in white matter was lower when compared to healthy controls (P < 0.05). Gray matter CVR was associated with white matter lesion volume in RVCL-S patients (r = -0.527, P = 0.01). In conclusion, impaired cerebrovascular reactivity may play an important role in the pathophysiology of RVCL-S and may be an useful early biomarker of cerebrovascular disease severity.

Clinical spectrum of hemiplegic migraine and chances of finding a pathogenic mutation.

OBJECTIVE: To investigate whether the clinical characteristics of patients with hemiplegic migraine with and without autosomal dominant mutations in CACNA1A, ATP1A2, or SCN1A differ, and whether the disease may be caused by mutations in other genes. METHODS: We compared the clinical characteristics of 208 patients with familial (n = 199) or sporadic (n = 9) hemiplegic migraine due to a mutation in CACNA1A, ATP1A2, or SCN1A with those of 73 patients with familial (n = 49) or sporadic (n = 24) hemiplegic migraine without a mutation in these genes. In addition, 47 patients (familial: n = 33; sporadic: n = 14) without mutations in CACNA1A, ATP1A2, or SCN1A were scanned for mutations in novel genes using whole exome sequencing. RESULTS: Patients with mutations in CACNA1A, ATP1A2, or SCN1A had a lower age at disease onset, larger numbers of affected family members, and more often attacks (1) triggered by mild head trauma, (2) with extensive motor weakness, and (3) with brainstem features, confusion, and brain edema. Mental retardation and progressive ataxia were exclusively found in patients with a mutation. Whole exome sequencing failed to identify pathogenic mutations in new genes. CONCLUSIONS: Most patients with hemiplegic migraine without a mutation in CACNA1A, ATP1A2, or SCN1A display a mild phenotype that is more akin to that of common (nonhemiplegic) migraine. A major fourth autosomal dominant gene for hemiplegic migraine remains to be identified. Our observations might guide physicians in selecting patients for mutation screening and in providing adequate genetic counseling.

Migraine prevalence in patients with unruptured intracranial aneurysms: A case-control study.

OBJECTIVES: Migraine is a suggested risk factor for aneurysmal subarachnoid hemorrhage (aSAH). An increased risk of aSAH in migraineurs may be explained by an increased prevalence of unruptured intracranial aneurysms (UIA). We performed a case-control study to compare lifetime migraine prevalence in patients with UIA, patients with a history of transient ischemic attact (TIA) or ischemic stroke and controls without a history of aSAH, TIA or ischemic stroke. MATERIALS AND METHODS: Patients with UIA were recruited from two university hospitals. Data on patients with TIA/stroke were retrieved from a previous study. Partners of patients with UIA or TIA/stroke were included as controls. Migraine history was assessed via a telephone interview based on the International Classification of Headache Disorders, second edition criteria. We calculated odds ratios (OR) for migraine with univariable and multivariable logistic regression analyses, adjusted for age, sex, hypertension and smoking. RESULTS: We included 172 patients with UIA, 221 patients with TIA or stroke, and 164 controls. In UIA patients, migraine prevalence was 24.4% compared with 14.6% in controls (UIA vs. controls; OR 1.9; 95% confidence interval [CI] 1.1-3.5) and 22.2% in TIA/stroke patients (UIA vs. TIA/stroke; OR 1.1; 95% CI 0.7-1.8). After adjustments, the OR for migraine in UIA patients versus controls were 1.7 (95% CI 1.0-3.1) and 0.9 (95% CI 0.5-1.0) versus TIA/stroke. Results were comparable for migraine with and without aura. CONCLUSIONS: Migraine prevalence is possibly increased in patients with UIA compared with controls and comparable with the prevalence in patients with TIA or stroke. Further studies are needed to confirm our findings and to investigate the underlying pathophysiology.

Identifying a gene expression signature of cluster headache in blood.

Cluster headache is a relatively rare headache disorder, typically characterized by multiple daily, short-lasting attacks of excruciating, unilateral (peri-)orbital or temporal pain associated with autonomic symptoms and restlessness. To better understand the pathophysiology of cluster headache, we used RNA sequencing to identify differentially expressed genes and pathways in whole blood of patients with episodic (n = 19) or chronic (n = 20) cluster headache in comparison with headache-free controls (n = 20). Gene expression data were analysed by gene and by module of co-expressed genes with particular attention to previously implicated disease pathways including hypocretin dysregulation. Only moderate gene expression differences were identified and no associations were found with previously reported pathogenic mechanisms. At the level of functional gene sets, associations were observed for genes involved in several brain-related mechanisms such as GABA receptor function and voltage-gated channels. In addition, genes and modules of co-expressed genes showed a role for intracellular signalling cascades, mitochondria and inflammation. Although larger study samples may be required to identify the full range of involved pathways, these results indicate a role for mitochondria, intracellular signalling and inflammation in cluster headache.

Detection of interferon alpha protein reveals differential levels and cellular sources in disease.

Type I interferons (IFNs) are essential mediators of antiviral responses. These cytokines have been implicated in the pathogenesis of autoimmunity, most notably systemic lupus erythematosus (SLE), diabetes mellitus, and dermatomyositis, as well as monogenic type I interferonopathies. Despite a fundamental role in health and disease, the direct quantification of type I IFNs has been challenging. Using single-molecule array (Simoa) digital ELISA technology, we recorded attomolar concentrations of IFNα in healthy donors, viral infection, and complex and monogenic interferonopathies. IFNα protein correlated well with functional activity and IFN-stimulated gene expression. High circulating IFNα levels were associated with increased clinical severity in SLE patients, and a study of the cellular source of IFNα protein indicated disease-specific mechanisms. Measurement of IFNα attomolar concentrations by digital ELISA will enhance our understanding of IFN biology and potentially improve the diagnosis and stratification of pathologies associated with IFN dysregulation.

Prevalence of lifetime depression in a large hemiplegic migraine cohort.

OBJECTIVE: To determine the prevalence of depression and determinants associated with depression in a large population of hemiplegic migraine (HM) patients. METHODS: We conducted a cross-sectional, validated questionnaire study among 89 well-defined HM patients and 235 headache-free controls. The prevalence of lifetime depression and its relation to migraine characteristics was assessed. RESULTS: HM patients had increased odds for lifetime depression (odds ratio 3.73, 95% confidence interval 2.18-6.38) compared with controls. Use of acute antimigraine medication was associated with lifetime depression. CONCLUSIONS: Depression is part of the monogenic hemiplegic migraine phenotype. Further studies are needed to elucidate the pathophysiologic role of HM genes in comorbid depression. For now, clinicians should take comorbid depression into consideration when starting prophylactic treatment of HM.

Familial and sporadic hemiplegic migraine: diagnosis and treatment.

OPINION STATEMENT: Hemiplegic migraine (HM) is a rare subtype of migraine with aura, characterized by transient hemiparesis during attacks. Diagnosis is based on the International Classification of Headache Disorders criteria (ICHD-II). Two types of HM are recognized: familial (FHM) and sporadic hemiplegic migraine (SHM). HM is genetically heterogeneous. Three genes have been identified (CACNA1A, ATP1A2, and SCN1A) but more, so far unknown genes, are involved. Clinically, attacks of the 3 subtypes cannot be distinguished. The diagnosis can be confirmed but not ruled out by genetic testing, because in some HM patients other, not yet identified, genes are involved. The presence of additional symptoms (such as chronic ataxia or epilepsy) may increase the likelihood of identifying a mutation. Additional diagnostics like imaging, CSF analysis, or an EEG are mainly performed to exclude other causes of focal neurological symptoms associated with headache. Conventional cerebral angiography is contraindicated in HM because this may provoke an attack. Because HM is a rare condition, no clinical treatment trials are available in this specific subgroup of migraine patients. Thus, the treatment of HM is based on empirical data, personal experience of the treating neurologist, and involves a trial-and-error strategy. Acetaminophen and NSAIDs often are the first choice in acute treatment. Although controversial in HM, triptans can be prescribed when headaches are not relieved sufficiently with common analgesics. An effective treatment for the severe and often prolonged aura symptoms is more warranted, but currently no such acute treatment is available. Prophylactic treatment can be considered when attack frequency exceeds 2 attacks per month, or when severe attacks pose a great burden that requires reduction of severity and frequency. In no strictly preferred order, flunarizine, sodium valproate, lamotrigine, verapamil, and acetazolamide can be tried. While less evidence is available for prophylactic treatment with topiramate, candesartan, and pizotifen, these drugs can also be considered. The use of propranolol in HM is more controversial, but evidence of adverse effects is insufficient to contraindicate beta-blockers.