| Sporadic hemiplegic migraine | |
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| This condition is inherited in an autosomal dominant manner |
Sporadic hemiplegic migraine (SHM) is a form of hemiplegic migraine headache isolated cases of which are observed. [1] It is a rare disease. It is considered to be a separate type of migraine. [2]
Sporadic hemiplegic migraine (SHM) has clinical symptoms identical to familial hemiplegic migraine (FHM) and distinct from migraine with aura. By definition the neurodeficits are supposed to be reversible. However, some cases with permanent neurological deficits have also been noted. [3]
CACNA1A, ATP1A2 and SCNA1 are genes associated with hemipeligic migraines, although many cases are considered idiopathic with no known cause. [4]
Diagnostic criteria require motor symptoms and at least one visual, sensory, or speech symptom, resembling basilar migraine. [5] They may also be associated with cerebellar signs. [6]
MRI features can be suggestive of cortical infarction and edema. [7]
Differential diagnoses can be: [5]
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Prevalence is estimated to be 0.005%. [8] The age of onset has been found to be under 15 years in 40% of cases while it is between 10 and 14 years in one third of the cases. Females outnumber males, 4 to 1. Only 3% have attacks after age 52. [2]
Migraine is a genetically influenced complex neurological disorder characterized by episodes of moderate-to-severe headache, most often unilateral and generally associated with nausea and light and sound sensitivity. Other characterizing symptoms may include nausea, vomiting, cognitive dysfunction, allodynia, and dizziness. Exacerbation of headache symptoms during physical activity is another distinguishing feature. Up to one-third of migraine sufferers experience aura: a premonitory period of sensory disturbance widely accepted to be caused by cortical spreading depression at the onset of a migraine attack. Although primarily considered to be a headache disorder, migraine is highly heterogenous neurological disease in its clinical presentation and is better thought of as a spectrum disease rather than a distinct clinical entity. Disease burden can range from episodic discrete attacks to chronic disease.
Headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches.
A medication overuse headache (MOH), also known as a rebound headache, usually occurs when painkillers are taken frequently to relieve headaches. These cases are often referred to as painkiller headaches. Rebound headaches frequently occur daily, can be very painful and are a common cause of chronic daily headache. They typically occur in patients with an underlying headache disorder such as migraine or tension-type headache that "transforms" over time from an episodic condition to chronic daily headache due to excessive intake of acute headache relief medications. MOH is a serious, disabling and well-characterized disorder, which represents a worldwide problem and is now considered the third-most prevalent type of headache. The proportion of patients in the population with Chronic Daily Headache (CDH) who overuse acute medications ranges from 18% to 33%. The prevalence of medication overuse headache (MOH) varies depending on the population studied and diagnostic criteria used. However, it is estimated that MOH affects approximately 1-2% of the general population, but its relative frequency is much higher in secondary and tertiary care.
Visual snow syndrome (VSS) is an uncommon neurological condition in which the primary symptom is that affected individuals see persistent flickering white, black, transparent, or coloured dots across the whole visual field. Other common symptoms are palinopsia, enhanced entoptic phenomena, photophobia, and tension headaches. The condition is typically always present and has no known cure, as viable treatments are still under research. Astigmatism, although not presumed connected to these visual disturbances, is a common comorbidity. As well, migraine and tinnitus are common comorbidities which are both associated with a more severe presentation of the syndrome. TMJ may also be a common comorbidity.
An aura is a perceptual disturbance experienced by some with epilepsy or migraine. An epileptic aura is a seizure.
Familial hemiplegic migraine (FHM) is an autosomal dominant type of hemiplegic migraine that typically includes weakness of half the body which can last for hours, days, or weeks. It can be accompanied by other symptoms, such as ataxia, coma, and paralysis. Migraine attacks may be provoked by minor head trauma. Some cases of minor head trauma in patients with hemiplegic migraine can develop into delayed cerebral edema, a life-threatening medical emergency. Clinical overlap occurs in some FHM patients with episodic ataxia type 2 and spinocerebellar ataxia type 6, benign familial infantile epilepsy, and alternating hemiplegia of childhood.
Alternating hemiplegia of childhood (AHC) is an ultra-rare neurological disorder named for the transient episodes, often referred to as "attacks", of hemiplegia that those with the condition experience. It typically presents before the age of 18 months. These hemiplegic attacks can cause anything from mild weakness to complete paralysis on one or both sides of the body, and they can vary greatly in duration. Attacks may also alternate from one side of the body to the other, or alternate between affecting one or both sides during a single attack. Besides hemiplegia, symptoms of the disorder include an extremely broad range of neurological and developmental impairments which are not well understood. Normally, hemiplegia and other associated symptoms cease completely with sleep, but they may recur upon waking.
Hemiplegic migraine is a type of migraine headache characterized by motor weakness affecting only one side of the body, accompanied by aura. There is often an impairment in vision, speech, or sensation. It can run in the family, called familial hemiplegic migraine, or in a single individual, called sporadic hemiplegic migraine. The symptoms can be similar to a stroke, and may be precipitated by minor head trauma. People with FHM are advised to avoid activities that may trigger their attacks.
Spinocerebellar ataxia type 6 (SCA6) is a rare, late-onset, autosomal dominant disorder, which, like other types of SCA, is characterized by dysarthria, oculomotor disorders, peripheral neuropathy, and ataxia of the gait, stance, and limbs due to cerebellar dysfunction. Unlike other types, SCA 6 is not fatal. This cerebellar function is permanent and progressive, differentiating it from episodic ataxia type 2 (EA2) where said dysfunction is episodic. In some SCA6 families, some members show these classic signs of SCA6 while others show signs more similar to EA2, suggesting that there is some phenotypic overlap between the two disorders. SCA6 is caused by mutations in CACNA1A, a gene encoding a calcium channel α subunit. These mutations tend to be trinucleotide repeats of CAG, leading to the production of mutant proteins containing stretches of 20 or more consecutive glutamine residues; these proteins have an increased tendency to form intracellular agglomerations. Unlike many other polyglutamine expansion disorders expansion length is not a determining factor for the age that symptoms present.
Episodic ataxia (EA) is an autosomal dominant disorder characterized by sporadic bouts of ataxia with or without myokymia. There are seven types recognized but the majority are due to two recognized entities. Ataxia can be provoked by psychological stress or startle, or heavy exertion, including exercise. Symptoms can first appear in infancy. There are at least six loci for EA, of which 4 are known genes. Some patients with EA also have migraine or progressive cerebellar degenerative disorders, symptomatic of either familial hemiplegic migraine or spinocerebellar ataxia. Some patients respond to acetazolamide though others do not.
Persistent aura without infarction (PAWOI) is a rare and seemingly benign condition, first described in case reports in 1982 as "prolonged/persistent migraine aura status", and in 2000 as "migraine aura status", that is not yet fully understood. PAWOI is said to possibly be a factor involved in a variety of neurological symptoms, including visual snow, loss of vision, increased afterimages, tinnitus, and others. The pathogenesis of PAWOI is unknown. It is not clear which medical examinations are useful in diagnosing PAWOI. At present, PAWOI is usually diagnosed solely based on the patient's current and past symptoms. It is possible that an "overactive brain" or a chemical imbalance underlies the disorder. Various medications have been tried as treatment, notably acetazolamide, valproate, lamotrigine, topiramate, and furosemide.
Cav2.1, also called the P/Q voltage-dependent calcium channel, is a calcium channel found mainly in the brain. Specifically, it is found on the presynaptic terminals of neurons in the brain and cerebellum. Cav2.1 plays an important role in controlling the release of neurotransmitters between neurons. It is composed of multiple subunits, including alpha-1, beta, alpha-2/delta, and gamma subunits. The alpha-1 subunit is the pore-forming subunit, meaning that the calcium ions flow through it. Different kinds of calcium channels have different isoforms (versions) of the alpha-1 subunit. Cav2.1 has the alpha-1A subunit, which is encoded by the CACNA1A gene. Mutations in CACNA1A have been associated with various neurologic disorders, including familial hemiplegic migraine, episodic ataxia type 2, and spinocerebellar ataxia type 6.
A cerebrospinal fluid leak is a medical condition where the cerebrospinal fluid (CSF) surrounding the brain or spinal cord leaks out of one or more holes or tears in the dura mater. A cerebrospinal fluid leak can be either cranial or spinal, and these are two different disorders. A spinal CSF leak can be caused by one or more meningeal diverticula or CSF-venous fistulas not associated with an epidural leak.
Vestibular migraine (VM) is vertigo with migraine, either as a symptom of migraine or as a related neurological disorder.
The classification of all headaches, including migraines, is organized by the International Headache Society, and published in the International Classification of Headache Disorders (ICHD). The current version, the ICHD-3 beta, was published in 2013.
Proline-rich transmembrane protein 2 is a protein that in humans is encoded by the PRRT2 gene.
Migraines are often hereditary. It is estimated that 60% of migraine cases are caused by genetics. The role of natural selection in the development of migraines is not known. Fitness-impairing disorders, including migraines, tend to disappear as a result of natural selection, and their frequency decreases to near the rate of spontaneous mutation. However, it is estimated that migraines affect 15-20% of the population and is increasing. This could suggest that a central nervous system (CNS) susceptible to severe, intermittent headache has been linked to an important survival or reproductive advantage. Five possible evolutionary explanations exist: i) migraine as a defence mechanism, ii) migraine as a result of conflicts with other organisms, iii) migraine as a result of novel environmental factors, iv) migraine as a compromise between genetic harms and benefits, and v) headache as a design constraint. These considerations allow the treatment and prevention of migraine to be approached from an evolutionary medicine perspective.
Illusory palinopsia is a subtype of palinopsia, a visual disturbance defined as the persistence or recurrence of a visual image after the stimulus has been removed. Palinopsia is a broad term describing a heterogeneous group of symptoms, which is divided into hallucinatory palinopsia and illusory palinopsia. Illusory palinopsia is likely due to sustained awareness of a stimulus and is similar to a visual illusion: the distorted perception of a real external stimulus.
Messoud Ashina is a Danish-Azerbaijani neurologist and neuroscientist. He is currently Professor of Neurology at the University of Copenhagen and Senior Consultant of Neurology at Copenhagen University Hospital - Rigshospitalet. He leads the Human Migraine Research Unit at the Danish Headache Center, Copenhagen University Hospital - Rigshospitalet. Ashina is also Director of the Danish Knowledge Center on Headache Disorders and Past President of the International Headache Society. As of 2023, Ashina is ranked as the world's leading expert on headache disorders by Expertscape.
A migrainous infarction is a rare type of ischaemic stroke which occurs in correspondence with migraine aura symptoms. Symptoms include headaches, visual disturbances, strange sensations and dysphasia, all of which gradually worsen causing neurological changes which ultimately increase the risk of an ischaemic stroke. Typically, women under the age of 45 who experience migraine with aura (MA) are at the greatest risk for developing migrainous infarction, especially when combined with smoking and use of oral contraceptives.