A gelastic seizure, also known as "gelastic epilepsy", is a rare type of seizure that involves a sudden burst of energy, usually in the form of laughing or crying. This syndrome usually occurs for no obvious reason and is uncontrollable. It is slightly more common in males than females. This syndrome can go for very long periods of time without a diagnosis, as it may resemble normal laughing or crying if it occurs infrequently. It has been associated with several conditions, such as temporal and frontal lobe lesions, tumors, atrophy, tuberous sclerosis, hemangiomas, and post-infectious foci, but mainly hypothalamic hamartomas. The term "gelastic" originates from the Greek word "gelos", which means laughter.
Signs and symptoms
The main sign of a gelastic seizure is a sudden outburst of laughter or crying with no apparent cause. The laughter may sound unpleasant and sardonic rather than joyful. The outburst usually lasts for less than a minute. During or shortly after a seizure, an individual might display some twitching, strange eye movements, lip smacking, fidgeting or mumbling. If a person who suffers from the seizures is hooked up to an electroencephalogram, it will reveal interictalepileptic discharges. This syndrome usually manifests itself before the individual reaches the age of three or four. The temporal lobes, and the hypothalamus are the areas of the brain with the most involvement with these seizures. This may cause learning disabilities, and faulted cognitive function as well. It is not uncommon for children to have tonic-clonic seizures, and atonic seizures directly following the seizure. Those that are associated with hypothalamic hamartomas may occur as often as several times hourly and typically begin during infancy. Seizures that occur in infancy may include bursts of cooing, respirations, giggling, and smiling. Due to early hypothalamic-pituitary-gonadal axis activation in girls who suffer from the seizures, it is not uncommon for them to display secondary sex characteristics before the age of eight.
Causes
A gelastic seizure is typically caused by a hypothalamic hamartoma, or a brain tumor. A hypothalamic hamartoma is defined as a benign mass of glial tissue on or near the hypothalamus. The size of the hamartoma can vary from one centimeter to larger than three centimeters. They can cause several different types of seizures including a Gelastic Seizure. These structures can be detected with different imaging modalities such as computed tomography, magnetic resonance imaging, Single Photon emission computed tomography and Positron Emission Tomography. A computed tomography scan of an individual with a hypothalamic hamartoma would reveal a suprasellar mass with the same density as brain tissue. Images of these masses are not enhanced with the use of contrast. However, although a computed tomography scan may be useful in diagnosing the cause of a seizure, in the case of a hypothalamic hamartoma, magnetic resonance imaging is the tool of choice due to the cerebrospinal fluid which defines these masses. Single Photonemission computed tomography may also be used which involves the use of a radiotracer that is taken up by the ictal region of the brain where, typically the tumor lies. Positron Emission Tomography using F-18 fluorodeoxyglucose show reduced metabolism at the site of seizure onset. Gelastic seizures have been observed after taking a birth control pill. Optic nerve hypoplasia is the only reported condition with gelastic seizures without hypothalamic hamartomas, suggesting that hypothalamic disorganization alone can cause gelastic seizures.
Diagnosis
A diagnosis is difficult, especially in children, due to the difficulty in differentiating between actual laughing or crying, versus a seizure that involves laughing and crying. In pre-verbal infants, a diagnosis may be impossible. A long history must be taken with a description of all the signs leading to and during the seizure. The episodes can also be confused with behavioral and emotional disorders. Some doctors ask parents to videotape the children's outbursts. The tapes may be difficult to obtain, but can be very helpful in speeding up the difficult diagnosis process. Diagnosis is also complicated due to the many possible causes of the seizures. Imaging is always helpful in an attempt to diagnose seizures caused by hypothalamic hamartoma. If there is evidence of this, the diagnosis takes much less time.
Management
Gelastic seizures are usually not responsive to pharmacotherapy. They can produce secondary seizure characteristics which may respond to medications or surgery. These options are not a guaranteed cure, and depend primarily on the individual patient's pathology. The treatment depends on the cause of the seizures. If the seizures are caused by a tumor, surgical removal can be attempted. However, surgical removal is not always an immediate cure, and there can be complications. Complications can include cerebral infarcts, and cognitive deterioration. Hormonal treatment can be attempted to help individuals with precocious puberty. Anti-epileptic drugs could be an option as well depending on the patient's criteria. These drugs could include carbamazepine, clobazam, lamotrigine, levetiracetam, oxcarbazepine and topiramate. However, usually none of these medications are capable of stopping the seizures from occurring, and like any medication, there may be undesirable side effects. There is also a specialized form of radiotherapy that may be an option depending on the tumor type and location. Once again, there are very few areas in the world that offer this treatment. Gamma kniferadiosurgery can be the treatment of choice when it comes to hypothalamic hamartomas. It is a low risk option due to its lower frequency of neurological deficits. It is recommended for patients with tumors that don't come into contact with the optic chiasm.
Prognosis
Like many other types of seizures, gelastic seizures are hard to control for an extended period of time. The best outlook is for children suffering the seizures due to a benign tumor in their hypothalamus. The removal of these tumors can be effective not only for the frequency of the seizures, but also the behavioral and cognitive symptoms that come along with the syndrome. Cases have also been described where that antiepileptic drugs have stopped seizures fully.
History
Very likely gelastic seizures were already recognized at the time of Babylonian medicine. A detailed description was given by the Scottish physician Robert Whytt in 1765, and the term "gelastic seizure" was coined in 1898 by the French neurologist, neuropathologist and epileptologist Charles Féré.
Media references
Gelastic syncope was also referred to in one paper also as "Seinfeld syncope" after an incident in which a patient repeatedly fainted while watching an episode of Seinfeld.
