When night waking is a seizure: gelastic seizures and hypothalamic hamartoma
Today I tell the story of a baby who could only sleep for 8 minutes at a time — and of the rare condition behind it.
Short answer: when is night waking not a sleep problem?
- Almost all night waking is behavioural — sleep associations, schedule, overtiredness. This episode is about the rare exception.
- A gelastic seizure is a brief seizure that looks like laughing, giggling or smirking for no reason. A dacrystic seizure looks like sudden crying or grunting.
- They are the most characteristic sign of a hypothalamic hamartoma, a rare benign growth on the hypothalamus that forms before birth.
- The pattern that stood out here: very short sleep episodes repeating all night, the same odd sound every time, no response to sleep training, and a baby exhausted during the day.
- If that sounds like your child, film an episode and take the video to a paediatrician or neurologist. Treatment exists and has improved a great deal.
Would you like to listen to a podcast episode about this? SOS - My baby wakes up every 8 minutes!
Why is my baby waking up every 20 minutes at night?
In the overwhelming majority of cases the answer is behavioural, and it is one of a short list: the baby cannot get back to sleep without the help they had at bedtime, the schedule is off, or they are overtired. That is what I write about almost every week — how sleep cycles and wake windows work, and how sleep crutches and overtiredness keep a baby waking.
But not every case is behavioural, and it is worth knowing what the exception looks like. In the story below, the parents had already done everything right: their son fell asleep independently, he had been sleep trained and night weaned, and his schedule was appropriate. None of it changed anything, because the cause was not a sleep problem at all.
What made this case unusual was the pattern rather than the amount of waking: extremely short sleep episodes repeating through the whole night, the same strange sound each time, the same behaviour appearing during the day as well, and a child who was tired all the time. If something about your baby's nights does not fit any behavioural explanation, record a video of an episode and show it to your paediatrician — that video is what eventually got this family an answer. I am a biologist, not a physician, and nothing here is a diagnosis.
A baby who woke up every 8 minutes, all night long
Imagine that your baby can only sleep for 8 minutes at a time. He goes to sleep, falls asleep independently, falls asleep easily, and after just 8 minutes of sleep he wakes up and he makes some strange noises, strange hooting sounds, and then goes back to sleep on his own. He goes to sleep and wakes up in 5 to 20 minute cycles for several times in the evening, and then these cycles get longer during the middle of the night. He only wakes up 4 to 5 times during this period, but after 4 a.m. he starts to wake up more often and more often until the morning.
During the day, the baby seems tired and struggles to stay asleep until his next nap, although he already follows a schedule for a younger baby. His parents actually sleep-trained their son when he was 4 months old, also night weaned him in an attempt to lengthen his sleep cycles, but it didn't really help. The baby already falls asleep independently, and he doesn't even seem to mind waking up in the middle of the night and staying awake for a few minutes and then going back to sleep. But still, the parents were really, really worried because this behavior just didn't seem normal.
I mean, babies sleep differently than adults, for sure, and there are very strange extreme cases of babies who cannot sleep very well. But even considering this, this case seemed to be out of the ordinary.
What the doctors said: it is normal, he will outgrow it
So the parents took this baby to several doctors, pediatricians, neurologists, and showed him videos of the baby sleeping at night. In one case, the baby even showed this behavior in front of the doctor because at that point he started to do this, to do these hooting noises during the day too. But the doctors couldn't say anything. They usually just said it's normal, that he will outgrow it, don't worry because he's developing well.
They said that the parents just might worry too much and maybe they just need to switch off the baby monitor for the night so that they can sleep better, and so on and so forth.
The symptom that led to the diagnosis
This story was posted on Reddit about 2 years ago by the baby's father in an attempt to find an answer and to find something that he can tell his wife to relax and calm down and maybe figure out together with the readers what could happen. He didn't find the answer then, but later, earlier this year, another symptom appeared. His son started to smile during these episodes when he's making this hoo-hoo sound, and that, I think that was the thing that helped them self-diagnose their son. So they looked up, they browsed the internet, trying to look up this strange grimacing smile together with the sound, and it turned out that it is called a gelastic seizure, or laughing seizure, and that it's a very characteristic symptom of so-called hypothalamic hamartomas.
Hypothalamic hamartomas are benign growths on the hypothalamus that cause this behavior. After diagnosing their son, they got connected with an epilepsy center and they confirmed the diagnosis. A few months later, their son went through brain surgery and has been seizure-free since then. By the time they got to the surgery, the little boy was having about 15 seizures per day, and they were getting more and more intense.
Luckily, after the surgery there were no more seizures, and he had his first full night of sleep at 30 months old, just 2 days after the surgery, and he has been sleeping through the night ever since. So this couple was lucky enough to catch this in time, and in fact this father wrote this post in an attempt to raise awareness of this very rare disease because most doctors don't see any cases throughout their lifetime. I am writing about it for the same reason.
When is night waking not a sleep problem?
So if someone's baby has extreme sleep behavior, it's not always a behavioral problem. It can be caused by serious conditions like this. Also, since I'm a biologist, after reading his post I got really interested in hypothalamic hamartomas, so I read up on them, and now I would like to talk about this rare condition.
What is a hypothalamic hamartoma?
So the hypothalamus is a part of the brain that is kind of in the middle, and it regulates many of the body's key processes like heart rate, blood pressure, body temperature, electrolyte balance, thirst, appetite, body weight, glandular secretions of the stomach and intestines. Also it influences the pituitary gland to release hormones. It influences sleep cycles, emotional responses, sexual behavior, and so on. So since it has so many complex functions, depending on where the growth is, it can have very different syndromes, and that's why it's usually very difficult to diagnose.
Also, it is very difficult to diagnose because it's so rare that most doctors don't see any cases in their life. So the symptoms can be very different from patient to patient, and also sometimes they are so mild that they are missed by the doctors.
What is a gelastic seizure (laughing seizure)?
But there are some common symptoms that patients with hypothalamic hamartomas have, and these are gelastic seizures, or it's like spontaneous laughing without any reason, or giggling or smirking, or dacrystic seizures, which are crying or grunting seizures, where the person with this condition seems to start crying for no reason. Also, children with hypothalamic hamartomas sometimes have developmental delays and/or precocious puberty. It means that the child can go through puberty at 2 years of age, for example. This is because of the hormonal functions of the hypothalamus.
When do the symptoms start?
So these symptoms usually start very early in life and sometimes start right after birth. In fact, hypothalamic hamartomas form during gestation, which means that in very rare cases they can be diagnosed in utero.
How are hypothalamic hamartomas treated?
Luckily, treatment options for this condition increased dramatically in the last decade. So while previously it was mostly brain surgery, which involved opening up the skull, now there are minimally invasive procedures that eliminate the tumor or decrease its size. Also, drugs improved a lot too that help patients deal with the seizures if surgery is not an option.
Where to learn more about hypothalamic hamartoma
I hope this helps raise awareness of this rare condition. If you would like to learn more about hypothalamic hamartomas, the best site is Hope4HH. It is hopeforhh.org, where there is a ton of information. Also you can find the closest treatment facilities, and you can learn more about treatment options and can also meet other families who have children with this condition.
There's also a very good blog where you can read stories from parents with children with HH, or from HH survivors themselves.
Frequently asked questions
What is a gelastic seizure?
A gelastic seizure is a brief seizure that looks like laughing, giggling or smirking with no reason behind it. The name comes from the Greek word for laughter. It is the most characteristic symptom of a hypothalamic hamartoma, and it can happen during sleep as well as during the day. A dacrystic seizure is the same thing with crying or grunting instead of laughing.
How can you tell a gelastic seizure from ordinary baby laughter?
Ordinary laughter has a cause and is social: something is funny, and your baby looks at you. A gelastic seizure typically comes out of nowhere, looks the same every single time, is very short, and can repeat many times a day — in the case in this episode, about fifteen times a day by the time of the diagnosis. If you are unsure, film it. A video is far more useful to a doctor than a description.
Are gelastic seizures dangerous?
The individual episode is short, but left untreated the seizures of a hypothalamic hamartoma tend to become more frequent and more intense over time, and the condition can also bring developmental delay or precocious puberty. That is why it needs a specialist rather than watchful waiting. Only a neurologist or an epilepsy centre can assess this.
What causes laughing seizures in babies?
The classic cause is a hypothalamic hamartoma: a benign growth on the hypothalamus that forms during gestation. Because the hypothalamus regulates so many different things — hormones, temperature, appetite, sleep cycles — the symptoms vary a lot from patient to patient, which is one reason the condition is so often missed. Gelastic seizures can occasionally originate elsewhere in the brain, so the diagnosis belongs to a specialist.
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