Reflex epilepsy has been defined as seizures caused
by external stimuli. Hot water epilepsy (HWE), an uncommon type of
reflex epilepsy, occurs while bathing with hot water(1,2). It was first
described in 1945 by Allen(2). It has been rarely reported from European
countries(3). Satishchandra, et al.(4) reported 279 cases with
HWE from southern India. They determined that the ratio of HWE to
epilepsies varied from 3.6% to 3.9%. Differences among countries may
depend on climate conditions, bathing habits, and genetic
susceptibilities. In this paper, we describe three cases of HWE.
Case Report
Case 1: A 21-month-old girl was brought to our
clinic with the complaint of convulsions while having a bath by pouring
hot water over the head since the age of 6 months. She used to become
floppy. This was associated by deviation of eyes, movements like hugging
her mother, and followed by loss of consciousness. She was born after an
uncomplicated pregnancy and her parents were unrelated. There were no
family history of epilepsy and no past history of febrile convulsions.
Psychomotor development was normal. Vital signs were stable. Height and
weight were consistent with age. Physical and neurological examinations
were normal.
Complete blood count, blood bio-chemistry, and urine
and blood amino acid profile were normal. Cerebral computed tomography
(CT), interictal electroence-phalography (EEG), and electrocardio-graphy
(ECG) were also normal.
She had previously four similar con-vulsions. First,
bathing with lukewarm water instead of hot water was recommended. Six
months later, at first follow-up visit, her convulsions had decreased
but did not completely stop during regular bath. We put her on
phenobarbital treatment. At second follow-up visit, she was
seizure-free.
Case 2: An 11-year-old female was brought with
the complaint of convulsions which started 5 months ago. She was taking
valproate (VPA) but she did not get benefit at all. She had deviation of
eyes, frothing from mouth, tonic-clonic movements, and loss of
consciousness while bathing by pouring hot water over the head. She was
born after an uncomplicated pregnancy from an un-consanguineous
marriage. There was no family history of epilepsy or febrile
convulsions. Psycho-motor development was normal. Vital signs were
stable. Height and weight were consistent with age. Physical and neuro-logical
examinations were normal. Complete blood count, blood biochemistry,
urine and blood amino acid profile were normal. Cerebral CT, intericatal
EEG and ECG were also normal.
Till the admission, she had three similar
convulsions. We planned to discontinue valproate gradually and
recommended bathing with lukewarm water instead of hot water. She became
seizure-free at the first follow-up visit.
Case 3: An 11-year-old girl was admitted to our
clinic with the complaint of generalized tonic-clonic convulsion while
bathing by pouring hot water over the head. It started 6 months ago. She
was taking valproate but her convulsions did not decrease. She was born
after an uncomplicated pregnancy from an unconsanguineous marriage.
There was no family history of epilepsy. Psychomotor development and
physical and neurological examinations were normal. Complete blood
count, blood biochemistry, urine and blood amino acid profile, cerebral
CT, interictal EEG, ECG were normal. She had five similar convulsions.
We recommended bathing with lukewarm water and planned to stop valproate
gradually. She was seizure-free at the first follow-up visit.
Discussion
Reflex epilepsies, a rare type of the epileptic
seizures, accounts for 6% of all epilepsies(5). HWE is a benign form of
reflex epilepsy precipitated by bathing with hot water. Males are
affected more than females (M-F: 2.6-3.6/1)(1,3).
A large number of patients with HWE (3.6-3.9% of all
epilepsies)(4) have been reported from India. There have been isolated
case reports from all round the world, such as Japan and Turkey. In
Turkey, people usually have a bath by sitting. Water is collected in a
bucket and it is poured over the head or body by using a mug. The
temperature of the hot water varies between 40 and 50ºC. Water poured on
head or body can cause seizure(4).
The pathophysiology of HWE has not been established
clearly but there are various hypothesis. Stensman and Ursing(6)
suggested that combination of factors such as contact of scalp with hot
water, temperature of water, and stimulation of specific cortical area
made up the triggering stimulus. In order to understand further the
pathophysiologic mechanisms underlying HWE, an experi-mental animal
model mimicking HWE has been developed(7). They postulated that patients
with HWE have an aberrant thermoregulatory system and were highly
sensitive to the rapid increase in temperature during bath with hot
water pouring over the head, which precipitated seizures. This aberrant
thermo-regulatory system appeared to be genetically determined.
Syzmonowicz and Meloff(1) demons-trated focal
activity in the temporal or frontal lobe and suggested that there could
be a structural lesion in the temporal lobe in HWE patients. However,
they failed to show these lesions by neuroimagings (CT and magnetic
resonance imaging). Later, Shankar and Satischandra(8) published autopsy
findings in three HWE patients and concluded that the most likely
pathophysiologic mechanism under-lying HWE could be aberrant
thermo-regulation in the genetically susceptible population with
possible environmental influences(9).
The most commonly seen seizure type in HWE is complex
partial seizure (CPS)(1,4,10). Satishchandra, et al.(4) found
that 67% of cases had CPS whereas 33% had generalized tonic-clonic (GTC)
seizure.
Interictal EEG studies in HWE are usually normal
whereas ictal EEG combined with hot water use shows usually focal
epileptic activities and paroxysmal discharges characterized by
secondary generalization. By ictal EEG recording, it is possible to make
differential dignosis of HWE from the disorders such as, vasovagal
syncope and aquagenic urticaria. But it is easily distin-guished from
febrile seizures by absence of fever in HWE before and after
seizure(3,4,9). In our cases, because of the difficulty in inducing hot
water epilepsy in our hospital conditions, we couldn’t obtain ictal EEG
and we tried to make differential dignosis of HWE from febrile
convulsions, vasovagal syncope, and aquagenic urticaria by a thorough
history.
The management in HWE is done simply by avoiding hot
water. However, approxi-mately one third of patients with HWE continue
to have seizures even during regular baths and develop nonreflex
seizures during follow-up. In these patients, conventional antiepileptic
drugs (AEDs) have been used. Satishchandra(11) suggested a new method of
intermittent oral prophylaxis with benzodiazepines before a head bath
especially in those patients who continue to have seizures during
regular baths. In one of our three cases, we used conventional AEDs
because she continued to have seizure in spite of bathing with lukewarm
water while two patients were already taking valproate.
HWE is a rare type of reflex epilepsy. It occurs
generally in children with normal psychomotor development and children
continue to develop normally after seizure. HWE has usually a favorable
prognosis by first avoiding lukewarm water and secondly using either
intermittent oral prophylaxis with benzodiazepines or conventional AEDs.
Contributors: FI collected the data and drafted
the manuscript. All authors were associated with finalization of the
manuscript and approved the draft.
Funding: None.
Competing interests: None stated.
