Serial magnetic resonance imaging findings during severe attacks of familial hemiplegic migraine type 2: a case report.

BACKGROUND: Hemiplegic migraines represent a heterogeneous disorder with various presentations. Hemiplegic migraines are classified as sporadic or familial based on the presence of family history, but both subtypes have an underlying genetic etiology. Mutations in the ATP1A2 gene are responsible for Familial Hemiplegic type 2 (FHM2) or the sporadic hemiplegic migraine (SHM) counterpart if there is no family history of the disorder. Manifestations include migraine with aura and hemiparesis along with a variety of other symptoms likely dependent upon the specific mutation(s) present. CASE PRESENTATION: We report the case of an adult man who presented with headache, aphasia, and right-sided weakness. Workup for stroke and various infectious agents was unremarkable during the patient's extended hospital stay. We emphasize the changes in the Magnetic Resonance Imaging (MRI) over time and the delay from onset of symptoms to MRI changes in Isotropic Diffusion Map (commonly referred to as Diffusion Weighted Imaging (DWI)) as well as Apparent Diffusion Coefficient (ADC). CONCLUSIONS: We provide a brief review of imaging findings correlated with signs/symptoms and specific mutations in the ATP1A2 gene reported in the literature. Description of the various mutations and consequential presentations may assist neurologists in identifying cases of Hemiplegic Migraine, which may include transient changes in ADC and DWI imaging throughout the course of an attack.

Astrocyte deletion of α2-Na/K ATPase triggers episodic motor paralysis in mice via a metabolic pathway.

Familial hemiplegic migraine is an episodic neurological disorder characterized by transient sensory and motor symptoms and signs. Mutations of the ion pump α2-Na/K ATPase cause familial hemiplegic migraine, but the mechanisms by which α2-Na/K ATPase mutations lead to the migraine phenotype remain incompletely understood. Here, we show that mice in which α2-Na/K ATPase is conditionally deleted in astrocytes display episodic paralysis. Functional neuroimaging reveals that conditional α2-Na/K ATPase knockout triggers spontaneous cortical spreading depression events that are associated with EEG low voltage activity events, which correlate with transient motor impairment in these mice. Transcriptomic and metabolomic analyses show that α2-Na/K ATPase loss alters metabolic gene expression with consequent serine and glycine elevation in the brain. A serine- and glycine-free diet rescues the transient motor impairment in conditional α2-Na/K ATPase knockout mice. Together, our findings define a metabolic mechanism regulated by astrocytic α2-Na/K ATPase that triggers episodic motor paralysis in mice.

Astrocytes in Atp1a2-deficient heterozygous mice exhibit hyperactivity after induction of cortical spreading depression.

The ATP1A2 coding α2 subunit of Na,K-ATPase, which is predominantly located in astrocytes, is a causative gene of familial hemiplegic migraine type 2 (FHM2). FHM2 model mice (Atp1a2tmCKwk/+ ) are susceptible to cortical spreading depression (CSD), which is profoundly related to migraine aura and headache. However, astrocytic properties during CSD have not been examined in FHM2 model mice. Using Atp1a2tmCKwk/+ crossed with transgenic mice expressing G-CaMP7 in cortical neurons and astrocytes (Atp1a2+/- ), we analyzed the changes in Ca2+ concentrations during CSD. The propagation speed of Ca2+ waves and the percentages of astrocytes with elevated Ca2+ concentrations in Atp1a2+/- were higher than those in wild-type mice. Increased percentages of astrocytes with elevated Ca2+ concentrations in Atp1a2+/- may contribute to FHM2 pathophysiology.

Higher burden of rare frameshift indels in genes related to synaptic transmission separate familial hemiplegic migraine from common types of migraine.

BACKGROUND: Familial hemiplegic migraine (FHM) is a rare form of migraine with aura that often has an autosomal dominant mode of inheritance. Rare mutations in the CACNA1A, ATP1A2 and SCN1A genes can all cause FHM revealing genetic heterogeneity in the disorder. Furthermore, only a small subset of the affected individuals has a causal mutation. We set out to investigate what differentiates patients with FHM with no mutation in any known FHM gene from patients with common types of migraine in both familial and sporadic cases. METHODS: 2558 male and female participants from a migraine cohort from the Danish Headache Center were included. 112 had FHM; 743 had familial migraine; and 1703 had sporadic migraine. Using a linear regression model, we analysed for over-representation of rare functional variants in FHM versus familial migraine and sporadic migraine. Post hoc analyses included pathway analysis and testing for tissue specificity. RESULTS: We found that patients with FHM have significantly more rare frameshift indels compared with patients with familial migraine and sporadic migraine. Pathway analysis revealed that the 'ligand-gated ion channel activity' and 'G protein-coupled receptor downstream signalling' pathways were significantly associated with mutated genes. We moreover found that the mutated genes showed tissue specificity towards nervous tissue and muscle tissue. CONCLUSION: We show that patients with FHM compared with patients with common types of migraine suffer from a higher load of rare frameshift indels in genes associated with synaptic signalling in the central nervous system and possibly in muscle tissue contributing to vascular dysfunction.

Biallelic loss of function variants in ATP1A2 cause hydrops fetalis, microcephaly, arthrogryposis and extensive cortical malformations.

The Na+/K+- ATPase acts as an ion pump maintaining the essential plasma membrane potential in all mammalian cell types, and is essential for many cellular functions. There are four α isoforms (α1, α2, α3 and α4) with distinct expression patterns, kinetic properties and substrate affinity. The α2-isoform is encoded by ATP1A2 and evidence supports its utmost importance in Cl- homeostasis in neurons, and in the function of respiratory neurons at birth. Monallelic pathogenic variants in ATP1A2 are associated with familial hemiplegic migraine type 2 (FHM2) and on rare occasions with alternating hemiplegia of childhood 1 (AHC1). To date, no instances of biallelic loss of function variants have been reported in humans. However, Atp1a2 homozygous loss of function knockout mice (α2-/- mice) show severe motor deficits, with lack of spontaneous movements, and are perinatally lethal due to absent respiratory activity. In this report we describe three newborns from two unrelated families, who died neonatally, presenting in utero with an unusual form of fetal hydrops, seizures and polyhydramnios. At birth they had multiple joint contractures (e.g. arthrogryposis), microcephaly, malformations of cortical development, dysmorphic features and severe respiratory insufficiency. Biallelic loss of function variants in ATP1A2, predicted to be pathogenic were found on whole exome sequencing. We propose that this is a distinctive new syndrome caused by complete absence of Na+/K+- ATPase α2-isoform expression.

Increased susceptibility to cortical spreading depression and epileptiform activity in a mouse model for FHM2.

Migraine is a highly prevalent, debilitating, episodic headache disorder affecting roughly 15% of the population. Familial hemiplegic migraine type 2 (FHM2) is a rare subtype of migraine caused by mutations in the ATP1A2 gene, encoding the α2 isoform of the Na+/K+-ATPase, predominantly expressed in astrocytes. Differential comorbidities such as epilepsy and psychiatric disorders manifest in patients. Using a mouse model harboring the G301R disease-mutation in the α2 isoform, we set to unravel whether α2+/G301R mice show an increased susceptibility for epilepsy and cortical spreading depression (CSD). We performed in vivo experiments involving cortical application of KCl in awake head-restrained male and female mice of different age groups (adult and aged). Interestingly, α2+/G301R mice indeed showed an increased susceptibility to both CSD and epileptiform activity, closely replicating symptoms in FHM2 patients harboring the G301R and other FHM2-causing mutations. Additionally, this epileptiform activity was superimposed on CSDs. The age-related alteration towards CSD indicates the influence of female sex hormones on migraine pathophysiology. Therefore, the FHM2, α2+/G301R mouse model can be utilized to broaden our understanding of generalized epilepsy and comorbidity hereof in migraine, and may be utilized toward future selection of possible treatment options for migraine.

Inefficient constitutive inhibition of P2X3 receptors by brain natriuretic peptide system contributes to sensitization of trigeminal sensory neurons in a genetic mouse model of familial hemiplegic migraine.

BACKGROUND: On trigeminal ganglion neurons, pain-sensing P2X3 receptors are constitutively inhibited by brain natriuretic peptide via its natriuretic peptide receptor-A. This inhibition is associated with increased P2X3 serine phosphorylation and receptor redistribution to non-lipid raft membrane compartments. The natriuretic peptide receptor-A antagonist anantin reverses these effects. We studied whether P2X3 inhibition is dysfunctional in a genetic familial hemiplegic migraine type-1 model produced by introduction of the human pathogenic R192Q missense mutation into the mouse CACNA1A gene (knock-in phenotype). This model faithfully replicates several properties of familial hemiplegic migraine type-1, with gain-of-function of CaV2.1 Ca(2+) channels, raised levels of the algogenic peptide calcitonin gene-related peptide, and enhanced activity of P2X3 receptors in trigeminal ganglia. RESULTS: In knock-in neurons, anantin did not affect P2X3 receptor activity, membrane distribution, or serine phosphorylation level, implying ineffective inhibition by the constitutive brain natriuretic peptide/natriuretic peptide receptor-A pathway. However, expression and functional properties of this pathway remained intact together with its ability to downregulate TRPV1 channels. Reversing the familial hemiplegic migraine type-1 phenotype with the CaV2.1-specific antagonist, ω-agatoxin IVA restored P2X3 activity to wild-type level and enabled the potentiating effects of anantin again. After blocking calcitonin gene-related peptide receptors, P2X3 receptors exhibited wild-type properties and were again potentiated by anantin. CONCLUSIONS: P2X3 receptors on mouse trigeminal ganglion neurons are subjected to contrasting modulation by inhibitory brain natriuretic peptide and facilitatory calcitonin gene-related peptide that both operate via complex intracellular signaling. In the familial hemiplegic migraine type-1 migraine model, the action of calcitonin gene-related peptide appears to prevail over brain natriuretic peptide, thus suggesting that peripheral inhibition of P2X3 receptors becomes insufficient and contributes to trigeminal pain sensitization.

Genetic studies of Polish migraine patients: screening for causative mutations in four migraine-associated genes.

BACKGROUND AND AIM: Migraine is the most common neurological disorder, affecting approximately 12 % of the adult population worldwide, caused by both environmental and genetic factors. Three causative genes have been identified in familial hemiplegic migraine (FHM) families: CACNA1A, ATP1A2, and SCNA1A. Recently, several mutations in KCNK18 have also been found as causative factors in migraine development. The aim of our study was to identify the genetic background of migraine in the Polish population. MATERIAL AND METHODS: Sixty patients with migraine without aura (MO) or with different types of migraine with aura (MA), including sporadic hemiplegic, familial hemiplegic, and probable familial hemiplegic, were screened for mutations in the four genes previously linked with different types of migraine (ATP1A2, CACNA1A, SCN1A, and KCNK18). RESULTS: Two missense mutations were found. One novel mutation in SCN1A, encoding α subunit of sodium channel, causing amino acid change M1500V localized to a region encoding inactivation loop between transmembrane domains III and IV of the channel, was detected in a female FHM patient. The M1500V mutation was absent in a group of 62 controls, as well as in the ExAC database. The second, already known missense mutation S231P in KCNK18 was found in a female MA patient. Additionally, a novel intronic polymorphism possibly affecting alternative splicing of SCN1A, at chr2:16685249, g.77659T>C, and c.4581+32A>G, located between exons 24 and 25, in a region encoding the inactivation loop of the sodium channel was found in a female MO patient. No mutations in ATP1A2 or CACNA1A were found in the study group. CONCLUSIONS: The presence of SCN1A mutations and absence of mutations in ATP1A2 or CACNA1A suggest that the Polish patients represent FHM type 3. On the other hand, the presence of KCNK18 mutation indicated another FHM subtype. It could be speculated that contrary to other European populations, the genetic basis of migraine in the Polish population involves mutations in genes not included in the study. Next-generation sequencing methods should be implemented to identify other migraine-associated variants.

Abnormal synaptic Ca(2+) homeostasis and morphology in cortical neurons of familial hemiplegic migraine type 1 mutant mice.

OBJECTIVE: Migraine is among the most common and debilitating neurological conditions. Familial hemiplegic migraine type 1 (FHM1), a monogenic migraine subtype, is caused by gain-of-function of voltage-gated CaV 2.1 calcium channels. FHM1 mice carry human pathogenic mutations in the α1A subunit of CaV 2.1 channels and are highly susceptible to cortical spreading depression (CSD), the electrophysiologic event underlying migraine aura. To date, however, the mechanism underlying increased CSD/migraine susceptibility remains unclear. METHODS: We employed in vivo multiphoton microscopy of the genetically encoded Ca(2+)-indicator yellow cameleon to investigate synaptic morphology and [Ca(2+)]i in FHM1 mice. To study CSD-induced cerebral oligemia, we used in vivo laser speckle flowmetry and multimodal imaging. With electrophysiologic recordings, we investigated the effect of the CaV 2.1 gating modifier tert-butyl dihydroquinone on CSD in vivo. RESULTS: FHM1 mutations elevate neuronal [Ca(2+)]i and alter synaptic morphology as a mechanism for enhanced CSD susceptibility that we were able to normalize with a CaV 2.1 gating modifier in hyperexcitable FHM1 mice. At the synaptic level, axonal boutons were larger, and dendritic spines were predominantly of the mushroom type, which both provide a structural correlate for enhanced neuronal excitability. Resting neuronal [Ca(2+)]i was elevated in FHM1, with loss of compartmentalization between synapses and neuronal shafts. The percentage of calcium-overloaded neurons was increased. Neuronal [Ca(2+)]i surge during CSD was faster and larger, and post-CSD oligemia and hemoglobin desaturation were more severe in FHM1 brains. INTERPRETATION: Our findings provide a mechanism for enhanced CSD susceptibility in hemiplegic migraine. Abnormal synaptic Ca(2+) homeostasis and morphology may contribute to chronic neurodegenerative changes as well as enhanced vulnerability to ischemia in migraineurs.

MR screening of candidates for thrombolysis: How to identify stroke mimics?

Stroke mimics account for up to a third of suspected strokes. The main causes are epileptic deficit, migraine aura, hypoglycemia, and functional disorders. Accurate recognition of stroke mimics is important for adequate identification of candidates for thrombolysis. This decreases the number of unnecessary treatments and invasive vascular investigations. Correctly identifying the cause of symptoms also avoids delaying proper care. Therefore, this pictorial review focuses on what the radiologist should know about the most common MRI patterns of stroke mimics in the first hours after onset of symptoms. The issues linked to the accurate diagnosis of stroke mimics in the management of candidates for thrombolysis will be discussed.

Sturge-Weber syndrome with late onset hemiplegic migraine-like attacks and progressive unilateral cerebral atrophy.

BACKGROUND: Sturge-Weber syndrome (SWS) is an uncommon etiology of hemiplegic migraine-like (HM-like) attacks, associated with epilepsy and mental retardation. CASE: We report the case of a 40-year-old woman with SWS who has been suffering from HM-like episodes since she was 24, with no history of seizure or mental retardation. Susceptibility weighted imaging (SWI)-MRI and CT scans have shown bilateral calcifications of the choroidal plexuses, a developmental venous anomaly with dilated transmedullary veins and a left parieto-occipital leptomeningeal angioma. (18)F-Fluorodeoxyglucose (FDG)-PET/CT revealed a diffuse left-hemisphere hypometabolism. The comparison between the MRI performed at the age of 24 and the one performed at the age of 40 highlighted a progressive unilateral fronto-temporo-parietal atrophy. Surprisingly, even now, cognitive functions of this patient are relatively preserved. Lamotrigine permitted an improvement of HM-like attacks. DISCUSSION: Explanations for this minimally symptomatic form of SWS may be the absence of seizure, the importance of her deep venous drainage, the absence of cortical calcification and white matter impairment in the affected hemisphere, and, paradoxically, the severely asymmetric cortical metabolism. Furthermore, this case reinforces the hypothesis that alteration of cerebral hemodynamics could precipitate the cortical spreading depression giving rise to migraine with aura. CONCLUSION: We propose to consider SWS as a cause of apparently isolated hemiplegic migraine and lamotrigine as a preventive medication in HM-like attacks.

Type III Sturge-Weber syndrome with migraine-like attacks associated with prolonged visual aura.

Sturge-Weber syndrome is known to be associated with migraine attacks and prolong aura even without cerebral infarction. We report the case of a 36-year-old woman with type III Sturge-Weber syndrome developing with prolonged left homonymous hemianopsia after an intractable migraine-like headache and becoming a permanent visual field defect at 18-month follow up. By adopting a multimodality imaging study, we suggested that the underlying mechanism of prolonged visual field defect was due to blood flow disturbance and vasogenic leakage under the leptomeningeal angioma combining with atrophy and the damaged integrity of white matter in right occipital lobe.

TNFα levels and macrophages expression reflect an inflammatory potential of trigeminal ganglia in a mouse model of familial hemiplegic migraine.

Latent changes in trigeminal ganglion structure and function resembling inflammatory conditions may predispose to acute attacks of migraine pain. Here, we investigated whether, in trigeminal sensory ganglia, cytokines such as TNFα might contribute to a local inflammatory phenotype of a transgenic knock-in (KI) mouse model of familial hemiplegic migraine type-1 (FHM-1). To this end, macrophage occurrence and cytokine expression in trigeminal ganglia were compared between wild type (WT) and R192Q mutant Ca(V)2.1 Ca(2+) channel (R192Q KI) mice, a genetic model of FHM-1. Cellular and molecular characterization was performed using a combination of confocal immunohistochemistry and cytokine assays. With respect to WT, R192Q KI trigeminal ganglia were enriched in activated macrophages as suggested by their morphology and immunoreactivity to the markers Iba1, CD11b, and ED1. R192Q KI trigeminal ganglia constitutively expressed higher mRNA levels of IL1ß, IL6, IL10 and TNFα cytokines and the MCP-1 chemokine. Consistent with the report that TNFα is a major factor to sensitize trigeminal ganglia, we observed that, following an inflammatory reaction evoked by LPS injection, TNFα expression and macrophage occurrence were significantly higher in R192Q KI ganglia with respect to WT ganglia. Our data suggest that, in KI trigeminal ganglia, the complex cellular and molecular environment could support a new tissue phenotype compatible with a neuroinflammatory profile. We propose that, in FHM patients, this condition might contribute to trigeminal pain pathophysiology through release of soluble mediators, including TNFα, that may modulate the crosstalk between sensory neurons and resident glia, underlying the process of neuronal sensitisation.

Increased susceptibility to cortical spreading depression in the mouse model of familial hemiplegic migraine type 2.

Familial hemiplegic migraine type 2 (FHM2) is an autosomal dominant form of migraine with aura that is caused by mutations of the α2-subunit of the Na,K-ATPase, an isoform almost exclusively expressed in astrocytes in the adult brain. We generated the first FHM2 knock-in mouse model carrying the human W887R mutation in the Atp1a2 orthologous gene. Homozygous Atp1a2(R887/R887) mutants died just after birth, while heterozygous Atp1a2(+/R887) mice showed no apparent clinical phenotype. The mutant α2 Na,K-ATPase protein was barely detectable in the brain of homozygous mutants and strongly reduced in the brain of heterozygous mutants, likely as a consequence of endoplasmic reticulum retention and subsequent proteasomal degradation, as we demonstrate in transfected cells. In vivo analysis of cortical spreading depression (CSD), the phenomenon underlying migraine aura, revealed a decreased induction threshold and an increased velocity of propagation in the heterozygous FHM2 mouse. Since several lines of evidence involve a specific role of the glial α2 Na,K pump in active reuptake of glutamate from the synaptic cleft, we hypothesize that CSD facilitation in the FHM2 mouse model is sustained by inefficient glutamate clearance by astrocytes and consequent increased cortical excitatory neurotransmission. The demonstration that FHM2 and FHM1 mutations share the ability to facilitate induction and propagation of CSD in mouse models further support the role of CSD as a key migraine trigger.

Sustained visual cortex hyperexcitability in migraine with persistent visual aura.

Persistent aura without infarction, a rare migraine disorder, is defined by aura symptoms that persist for >1 week without radiological evidence of cerebral infarction. To unveil its pathophysiological mechanisms, this study used magnetoencephalography to characterize the visual cortex excitability in persistent aura by comparison with episodic and chronic migraine. We recruited six patients with persistent visual aura, 39 patients with episodic migraine [12 in ictal phase; 27 in interictal phase (with aura, n = 9; without aura, n = 18)], 18 patients with chronic migraine and 24 healthy controls. Five sequential blocks of 50 neuromagnetic prominent 100 ms responses were obtained, and the dynamic change in visual cortex excitability was evaluated by the percentage changes of individual mean prominent 100 ms amplitudes at blocks 2-5 compared with block 1, with a significant increase indicating potentiation. We found that in patients with persistent aura, there was significant potentiation during ictal periods (P = 0.009 and 0.006 at blocks 2 and 5, respectively), and the excitability change was inversely correlated with the duration of aura persistence (correlation coefficient -0.812, P = 0.050, block 2). The interictal recordings (n = 3) also showed potentiation. In terms of the other migraine spectrum disorders, persistent aura differed from episodic migraine in the presence of ictal potentiation. Persistent aura further differed from chronic migraine in the absence of interictal potentiation in chronic migraine. There was a higher percentage change of response amplitude at the end of stimulation (block 5) in persistent aura (43.3 ± 11.7) than in chronic migraine (-7.6 ± 5.5, P = 0.006) and ictal recordings of episodic migraine (-4.9 ± 9.6, P = 0.020). Normal control subjects had no significant response changes. This magnetoencephalographic study showed that the visual cortex in patients with persistent visual aura maintains a steady-state hyperexcitability without significant dynamic modulation. The excitability characteristic supports persistent visual aura as a nosological entity in migraine spectrum disorders and suggests a pathophysiological link to sustained excitatory effects possibly related to reverberating cortical spreading depression.

Migraine attacks, aura, and polycythemia: a vasculoneural pathogenesis?

Headache is a frequent symptom of polycythemia. A case study of a polycythemia vera patient affected by migraines, with and without aura, who developed headache attacks with aura in association with elevated haematocrit and haemoglobin levels is presented. A vasculoneural pathogenesis is supposed.

Child neurology: Migraine with aura in children.

The differential diagnosis for an acute hemiparesis in a child includes stroke, Todd paralysis, and hemiplegic migraine. In the context of an illustrative case, this review highlights the differences in clinical presentation among these entities and an approach to the diagnostic workup. Migraine with aura in children is reviewed, including migraine equivalents such as abdominal migraine and the particular presentation of hemiplegic migraine. An approach to the prophylactic and acute treatment for children with migraine with aura is offered.

Rupture of middle fossa arachnoid cyst simulating new-onset migraine with aura.

Arachnoid cysts represent a common, innocent, finding in routine neuroimaging of headache patients. We present the first report of symptomatic migraine with aura caused by the spontaneous rupture of a middle fossa arachnoid cyst into the subdural space. Brain imaging enabled an accurate diagnosis and, subsequently, adequate surgical management.