Hot-water epilepsy

My teacher, guide, and my mentor Prof. K. S. Mani aptly called “Father of Indian Epileptology” has first described hot water epilepsy way back in late 70’s. Some people even doubted whether such an entity exists. As I used to see these cases almost in the every outpatient clinic at National Institute of Mental health and neurosciences, I started thinking about it and many questions arise in my mind. This formed my research questions and started working on since 1980’s. Today, I am giving my talk on the culminated research experience, which I have acquired in the last three decade. I have titled my talk as “Bridge over Troubled Waters,” which is very famous poem. I have taken the literal meaning here and look at the water which posed the problem in the form of Epilepsy” How we have gone on to solve this mystery? Introduction Seizures that precipitated by a sensory stimulus are described as “reflex or sensory epilepsy” are interesting, and often provide insight into the pathogenesis of epilepsy in general and reflex epilepsy in particular. Penfield was the first author to use the term “sensory precipitation of seizures” in 1941 as the seizure-inducing mechanism rather than the cause.[1] One of such epilepsy is precipitated by the stimulus of bathing with hot water pouring over the head and better known as hot water epilepsy (HWE).[2–8] It is also variably known as water-immersion epilepsy or bathing epilepsy.[9–12] History Though, it was first described way back in 1945 from New Zealand,[13] there were isolated reports from all round the world: Australia,[14] United States of America,[15] Canada,[5] United Kingdom,[16] and Japan.[1718] However, a large number of patients with this type of HWE have been reported from India, particularly south India.[6–9] A large cohort of 279 cases of HWE from a University Hospital and Tertiary Care Centre, National Institute of Mental health and Neurosciences (NIMHANS), was evaluated over a 4 year period (1980-1983).[67] The detailed initial description and subsequent works on this geographically specific epilepsy syndrome - HWE have been carried out by two researchers K. S. Mani and P. Satishchandra, both belonging to the same region and the institute.[236–1920] Epidemiology A House-to-house Bangalore urban-rural neuroepidemiologic survey of 102,557 population from South India, reported that HWE accounts for 6.9% of all epilepsies in this community, giving a prevalence rate of 60 per 100,000 (unpublished data). Mani et al., published an epidemiologic study from Yelandur, a rural area near Mysore from Karnataka, and quoted a prevalence rate of 255/100,000 for HWE.[20] The classification proposed by the International League Against Epilepsy task force in 2001 includes HWE under the reflex epilepsies.[21] In a recent study from this center on 70 patients, majority of the patients belonged to Mandya: 30.5%, Ramanagara: 30.0% and Mysore: 15.2% districts of Karnataka.[22] Phenotypic description Like any other South Indians take bath daily, but as a customary practice of washing of the head is done generally once in 2-15 days. Temperature of the hot water used for bathing ranges between 40°C and 50°C (ambient room temperature, 25-30°C). Usually water is collected in a bucket, and water is poured over the body or head by using a tumbler or mug in this part of the country. Following that episodes of HWE are precipitated in some individuals. However, less commonly HWE in people using a shower or tub bathing have also been noted. This type of HWE has been reported as isolated cases from people having hot showers or tub baths from all over the world, including the United States, Canada, UK, Ireland, and Australia. Small series of HWE have been published from Japan and recently from Turkey.[23] In a recent study on 70 patients of HWE from this center by Meghana et al., (2012) 45 subjects (M:F 37:8; age at presentation: 24.6 ± 10.5 years; age at the onset of HWE 18.7 ± 10.2 years) had features of ‘HWE alone’ while 25 subjects (M:F = 18:7; age at presentation: 26.8 ± 7.9 years) had ‘HWE with spontaneous seizure’ (age at the onset of HWE in “HWE with spontaneous seizure’: 16.8 ± 10.3 years; duration of ‘HWE with spontaneous seizure”: 116.5 ± 66.9 months; duration of “spontaneous seizure”: 91.2 ± 8.9 months; average interval between “HWE and spontaneous seizure”: 33.9 ± 0.6 months). Table 1 depicts the phenotypic and demographic features of the two subgroups of patients with HWE in the series by Meghna et al., (2012; 22). Among 45 cases of “HWE alone”, 10 used had seizures while pouring even luke warm water and one patient had a seizure while washing face with hot water. 23 subjects out of 70 had 1:1 episodes. Among those with HWE alone, eight subjects could not avoid hot water bath and had increased frequency of attacks (2-3 seizures/week). One-third of patients with ‘HWE alone’ subgroup, the attacks occurred whenever they used to take hot water head bath (1:1): Men - 35% and women - 17%. In those with “HWE with spontaneous seizure” subgroup, 10 patients had 2-3 seizures/week. Ten patients had 1:1 episode of seizures with hot water bath. In the “HWE with spontaneous seizure” subgroup, the manifestation interval between reflex HWE and spontaneous seizure was variable: <2 weeks: 8; <6 months: 4; <2 years: 13. Children who got “HWE alone” in early age (age of onset was ≤ 12 years) progressed to develop “spontaneous seizure”. In the group of patients of HWE with spontaneous seizure (n = 25), 14 subjects (56%) had onset of HWE on or before 12 years of age. The family history of spontaneous epilepsy was 33.3% in “HWE alone” and 36.4% in “HWE with spontaneous seizure.” Family history of HWE in “HWE alone” group was 26.8% and 13.6% in “HWE with spontaneous seizure.” About, 22% of patients with “HWE alone” and 18.2% of those with “HWE with spontaneous seizure” had a previous history of febrile convulsion.Table 1: Comparison of various clinical features of both the subgroups of HWEChildren are more frequently affected, although, it has been reported in adults from our center.[236–8] Males are affected more frequently than female subjects (2-2.5:1). Generally, the frequency of these seizures depends on the frequency of head bathing. Five to 10% of these patients have seizures even during a body bath when water is not poured over the head, at a later stage in the natural history. The most common type of seizures is of complex partial with or without secondary generalization. It is characterized by a dazed look, sense of fear, irrelevant speech, and visual and auditory hallucinations with complex automatisms. About 1/3rd of all reported cases have primary generalized tonic-clonic seizures. These seizures have been witnessed in the laboratory and have been documented on a video in few instances.[5–7151722] About 10% of these patients, who express intense desire and continue to pour hot water over the head until they lose consciousness, could be considered to have “self-induced HWE” (unpublished observation). These seizures last 30 s to 3 min and could manifests either at the beginning or at the end of the bath. Spontaneous non-reflex epilepsy has been reported to occur few years later in 16-38% of patients.[36–822] A history of epilepsy among the family members has been reported in 7-22.6% of cases. There are no neurologic deficits in these patients. Seizure semiology was ascertained in the study by Meghana et al.,[22] was based on history, i.e., eye witness account (n = 62) or video documentation (n = 8). Subjects with “HWE alone” had complex partial seizure (CPS) in 58.5% and CPS with secondary generalization in 41.5%. Voluntary act of taking bath stopped when seizure began, and similarly, when the relatives were pouring hot water on the head, they could recognize the onset and stopped further pouring of hot water. Majority of the patients (60%) got an attack wherein they would sit flexing their body and closing ears with both hands with aura of fear, for few seconds followed by the seizure. They had varied manifestations which included loss of orientation and awareness, staring look, behavioral arrest, irrelevant speech, déjà vu, among feeling like fainting etc., each lasting for few seconds to minutes. By and large, except for a tendency to look around aimlessly, rarely wandering (one), praying (one) there was no other motor phenomena. Post ictal headache and sleep were present. Eleven patients gave a history of secondary generalization at the end of the hot water head bath. Twenty five subjects of the “HWE with spontaneous seizure” subgroup had CPS during sleep with semiology of screaming loudly, tonic flexion of the body followed by secondary generalization. The phenomenon of “self-induction of HWE” was seen in 23 out of 70 patients (32.8%), who also had frequent attacks. They get an aura of pleasure during hot water both and would continue to pour the hot water on head until they had seizure. 18 patients also gave a history of self-limiting attacks, wherein patients could control the feeling of euphoria and thereby abort the attack. A comparison of clinical features of both the subgroups is provided in Table 1. Electroencephalography features Interictal scalp electroencephalography (EEG) is usually normal, but 15-20% might show diffuse abnormalities.[3–8] Lateralized or localized spike discharges in the anterior temporal regions have been reported in a few isolated cases.[152122] Ictal EEG recording has its own technical limitations and is difficult to obtain; however, there are seven reports in the literature demonstrating the ictal EEG recordings during provocation in water-immersion epilepsy. They had demonstrated left temporal rhythmic delta activity,[15] sharp and slow waves in the left hemisphere bilateral spikes,[16] and temporal activity.[1112] Simultaneous split-screen video-EEG recording in one patient with “bathing” epilepsy demonstrated delta waves starting from the right hemisphere with rapid secondary generalization.[24] In the study by Meghana et al., (2012), EEG was performed in all 70 patients with HWE and was normal in 55 and abnormal in 15. In the ‘HWE alone’ subgroup (n = 45), nine had abnormal EEG while in the among “HWE with spontaneous seizure” subgroup (n = 25), six had abnormal EEG. The abnormalities in the majority were located in the fronto-temporal region on either or both sides [Figure 1].[22]Figure 1: Electroencephalography of patient with hot water epilepsy with spontaneous seizures showing focal sharp wave discharges mainly from left temporal regionPathogenesis The exact pathogenesis of this unique form of reflex epilepsy is not known and therefore some hypotheses have been put forward. Stensman and Ursing[15] suggested that this type of epilepsy is precipitated by complex tactile and temperature dependent stimuli. Although, it was possible to provoke the seizure in the laboratory by pouring hot water over the heads of these patients, hot-water towels, sauna, or blowing hot air on the head failed to induce seizures, suggesting that the triggering stimulus is complex and would involve a combination of factors such as (a) contact of scalp with hot water, (b) temperature of water, and (c) specific cortical area of stimulation. As the CPSs are the commonest variety of seizure, and ictal EEG had demonstrated focal activity in the temporal or frontal lobe, Syzmonowicz and Meloff[5] suggested that there could be a structural lesion in the temporal lobe. However, computed tomography (CT) and magnetic resonance imaging (MRI) in patients with HWE have negated the presence of any focal structural lesions in the majority. Even if such lesion were present, it is still not clear whether the mechanism of seizure depends on locally increased neuronal excitability in the lesions, or pathologic involvement of lower centers such as hypothalamus, or both.[16] Shankar and Satishchandra reported pathological findings in three of their patients with HWE.[25] From 11% to 27% of the HWE patients reported from India had history suggestive of febrile convulsions before the development of this reflex epilepsy.[34722] This association has not been noted from other parts of the world. Repeated exposure of the heads of adult rats to hot water (45°C) induced experimental seizures, which is comparable to the phenomenon of kindling by repeated stimulation with subthreshold electrical current. Klauenberg and Sparber[26] called this “hyperthermic kindling.” Satishchandra et al.,[727] postulated that the similar phenomenon of “hyperthermic kindling” might be responsible for the development of HWE in humans. Further to understand the pathophysiological and pharmacological mechanisms underlying HWE, an experimental animal model mimicking HWE in its entirety ([a] precipitating stimulus, [b] the ictal events, and [c] EEG comparable to those of human HWE] was developed by the same group.[2728] They demonstrated “hyperthermic kindling” in this model on repeated stimulation and confirmed it by Timm staining (OK). Translating this information to human, the authors recorded the body temperature through a thermistor kept inside the auditory canal in the susceptible human with HWE during a hot-water head bath.[2920] This demonstrated a “rapid spurt” in the temperature of 2-3°F within a short span of 2 min. It takes 10-12 min for this temperature to return to the baseline, once the bath is completed. This is in comparison with the increase of 0.5-0.6°F noted in the normal healthy volunteers, which return to the baseline immediately, at the end of the bath. This suggests that this special form of induced hyperthermia could be responsible for causing HWE in these susceptible individuals.[28–30] We postulated that HWE patients probably have an aberrant thermoregulatory system and are extremely sensitive to the rapid increase in temperature occurring during hot water head baths, which precipitates seizures. This aberrant thermoregulation seems to be genetically determined, and further work to elucidate this hypothesis is under way. The rat model described simulates human HWE and gives new evidence that human HWE is a “hyperthermic” seizure with probable kindling process.[30–32] Autonomic Involvement in HWE We recently characterized the role of autonomic nervous system function in reflex epilepsy mainly in HWE. Comparison of the cardiac autonomic functions in patients with HWE (n = 90), spontaneous epilepsy (n = 40) and healthy volunteers (n = −51) was done. We evaluated the relationship between phenotypic observations and cardiac autonomic parameters in all the reflex epilepsies and non-reflex spontaneous epilepsy. This study has demonstrated an impaired sympatho-vagal balance characterized by increased sympathetic activity and reduced parasympathetic activity in patients with HWE. The HWE with spontaneous CPS had more deteriorating cardiac autonomic nervous system control than HWE due to long duration of illness. There was no significant effect of carbamazepine (CBZ) drug on ANS. In summary, reflex epilepsy have mild to moderate autonomic dysfunction. This study also supported the hypothesis of hypothalamic dysfunction and a distinctive sympathetic dysfunction in patients with HWE.[3334] Functional Imaging Observations As there are no structural changes in the MRIs of this human HWE, it is more likely that functional changes in these susceptible human could induce seizures. To demonstrate we recently a study of and ictal computed tomography in 10 HWE patients who had HWE, by using the had and scalp EEG. Interictal were performed in all these patients by using a patients were with hot-water head bath their Five patients who had HWE in the laboratory were at the onset of the ictal and were These were from This demonstrated ictal in the temporal and on the left in three and on the right in two patients, with to the In a similar to five patients with HWE the - 3 ictal and 2 There were changes in temporal This study demonstrated functional involvement of these in triggering of HWE family seen in about HWE patients from India, have suggested involvement of of the of HWE were In an to understand the of HWE, we have seven HWE with of their members affected with the ascertained at These have of two for HWE at and Among the family was the and with 10 affected and members [Figure This family was through 10 who was with HWE at the age of EEG generalized discharges from the left temporal region of the HWE in the family and six - and in an with A about was carried out for family and were with a frequency of and Following based of family the was at = and of for the at region [Figure of five HWE for on further the evidence of to the same region with three out of five of to the same The and the of the In a similar study of family [Figure significant was on [Figure with the of at of for the The and and of this The interval about of large family of HWE with significant was on with the of at of for the [Figure the of the family and the hot water epilepsy at the of family in and 3 are by Seizure and age at onset are The HWE is in the It the of the family and the hot water epilepsy is in the water bath triggering reflex epilepsy and to febrile convulsions in similar for febrile convulsions have been to and However, the and for HWE [Figure are from the in febrile convulsions suggesting that HWE and are clinical of prevalence of HWE in South India role of a effect for the HWE be genetically and could be responsible to increased prevalence of this in of two for HWE is an of the responsible The interval at and interval at known to be in the human Among the known from the the for and were the most for HWE as epilepsies by in are a large of and which are in of neuronal also in this However, of these not a involvement of these two and at were for but were However, of in the in the such as or at these to be Some about the at which could of seizures have from animal are also known to occur in in a known to for seizures due to in an for in the stage of the These findings an involvement of of in seizure to HWE in in the nervous system development in and and of neuronal and in the region and are to be for and in the of are for the in the Further work in the of these and other such to the responsible for HWE is in HWE in human are often in two (a) using water for a head bath or with hot and (b) use of such as or of patients with HWE with for a period of 14 ± that could be had a in but to have seizures at their last It is to that 10% of these HWE patients that HWE. From to of subjects with HWE continue to have seizures even during baths and develop non-reflex seizures during This is evidence for the phenomenon of “hyperthermic kindling” in human, the of kindling in human is still In of the that HWE is a type of “hyperthermic” seizure to febrile Satishchandra et a of with They the use of of before a head bath and avoid it every These patients not any other on a thereby the and of these are to be used if the patients develop non-reflex seizures from of patients with HWE was carried (a) HWE (n = (b) HWE (n = (c) (n = of patients on and might be in the of non-reflex In the recent by Meghana et al., (2012) from this it was that patients with “HWE alone” (n = to avoid hot water head bath and is in HWE with spontaneous seizures. initial majority of the “HWE alone” subjects were drug the patients were to avoid hot water bath. was who could not avoid having hot water head bath on some They were about before hot water head bath. ± of stopped taking hot water head bath and were seizure The patients were on patients while six patients even three patients were seizure with but six patients had seizures. They were and all were seizure initial among 25 patients of the HWE with spontaneous seizure subgroup were drug patients were on and 4 were on and and patients (n = were and were to use luke warm water for head bath. a of ± all were seizure The development of experimental animal and of human HWE patients have new into the pathogenesis of this unique type of epilepsy as a type of “hyperthermic” seizure. thermoregulation in the genetically susceptible population with possible could be the mechanism responsible for this type of epilepsy. practice of using as rather than of has been as the specific of for this type of epilepsy. We S. K. K. S. Meghana for their association with research work on HWE at various

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.