A question from a father and some answers for seizures due to hypoglycemia

A father from the Netherlands recently wrote to me about his son. I thank him for his question.  He asked me a few very specific questions. I am reproducing them here as I feel it shall aid other people. My response to his questions follows. Names have been removed to maintain privacy.

QUESTION:

My son is diabetic type 1, since his 5th year. And he had several seizures in the last 5 years. Mostly once a year, every time he had a hypoglycaemia.
The last time he had a epileptic seizure, with a fracture of thoracic vertebra 2. I have made a MRI scan of the brains, but everything seems normal.
Are there other investigations necessary to be sure it is an epileptic insult due to hypoglycaemia, instead of real epilepsy

HK

ANSWER:

Dear HK,

                                  thank you for writing in to me. If I get you right you are saying that all of your son’s seizures have occured in the setting of hypoglycemia. Do you by any change recall what was his blood sugar during these ictal episodes. For a seizure to occur due to hypoglycemia, the blood sugar has to usually fall down to an extremely low level (we call this neurohypoglycemia). As you are aware the brain needs sugar for energy and its metabolism so when blood sugar falls down to the range of 60 mg/dl or less, that is when a seizure occurs. The seizure in the setting of hypoglycemia is usually a generalized convulsion. That said I and many other physicians have seen patients presenting to the ER with focal findings suggestive of a stroke only to find them completely reverse once the blood sugar was corrected.

I do have a few practical suggestions for you:

–have a home blood glucose meter and check your son’s blood sugar at various times during the day such as in the early morning when he wakes up (fasting blood sugar), prior and after lunch (post prandial blood sugar) and finally before he heads to bed during the night.  Do this for about 2 weeks and keep a record of the values in a notebook. This shall prove to be tremendously helpful to you as a parent and his physician to see how his blood sugar fluctuates during the day. Are there times when his blood sugar falls down/ bottoms out unexpectedly.

–a seizure due to hypoglycemia is rapidly reversible and in fact can be aborted with intravenous dextrose solution. Now it may be hard to administer intravenous dextrose at home.

–another very important point which comes to mind is why is he having so frequent hypoglycemic episodes. This shall require a thorough review by his endocrinologist. His insulin dose may need to be adjusted and/or he may warrant frequent small meals during the day to prevent his sugar from suddenly dropping.

–now to your final question: does your son actually have underlying epilepsy per-se. The answer to that depends upon this:

                -has he ever had a seizure in the setting of normal glucose level?

                -an EEG study shall be extremely useful. If the electroencephalogram shows inter-ictal epileptiform activity then likely your son does suffer from epilepsy. Remember in patients with seizures due to hypoglycemia per-se, the EEG between the seizures should be normal.

                -a routine EEG (30 minutes study) can fail to reveal an answer. In that case a long term EEG monitoring study (24-72 hours either in the hospital or in an outpatient setting) may aid in characterization of his typical events.

-as you may have guessed right, patients with seizures due to hypoglycemia per se do not need to be on anti-convulsant therapy. In these patients what we need to ensure that they do not become hypoglycemic. No hypoglycemia means no seizures.  On the other hand if your son does have underlying epilepsy, he shall warrant anti-convulsant therapy.

                -also a neuroimaging study (ideally MRI of the brain) may he helpful to rule out any intracerebral structural cause of seizure.

I hope you find this information helpful. Please feel free to contact me again.

Personal Regards,

Nitin Sethi, MD

Syncope Vs Seizure: the quest for an answer

One of the readers of my blog sent me an interesting query. Here is her history. My response to it follows. I have deleted her name and hidden her email address to maintain her confidentiality.


HISTORY

Hi! I was grocery shopping in Wal-mart when I had my episode. I was walking to the front of the store after shopping for about an hour. My vision kept blacking out. It was like someone just turned out the lights. I would be able to see again and I would be standing there staring at something. This happened about 4 or 5 times over a ten minute span. The next thing I knew I was waking up in the hospital. Apparently I hit the ground started convulsing, my eyes rolled back and I was foaming at the mouth. I bit the side of my tongue, my body was horribly sore the next couple of days, but I didn’t have any bladder issues. I had no memory of the seizure or what had happened. I kept going in and hour for the next couple of hours. I busted my head on the floor which required staples. I had memory problems and balance issues for the next week. I then made an appointment with a neurologist. He thinks I have syncope. He sent me for my EEG to rule out epilepsy, but we haven’t got the results back yet. While I was having my EEG I started having facial spasms during the flashing light portion of the test. I’m reading about syncope and some of it just doesn’t fit. I am a HUGE salt eater. I crave salty foods all day! So if that was it, wouldn’t my diet be treating the syncope? Also, my sister has epilepsy. Her seizures are triggered by flashing lights. I have never had a seizure before. I have passed out in the past, but it was because of hypoglycemia. I don’t have any issues with heat or pain or seeing blood. It just doesn’t affect me. I just don’t know if he’s got the correct diagnosis and would like someone else’s opinion. Thanks!

Dear A,
                 thank you for writing in to me.  Your history has intrigued me and hence I shall dwell over it a little before offering my humble opinion.  It goes without saying, this opinion is offered without taking your history in person and examining you.  You should follow what your doctor tells you.  He/ she shall be the best person to guide further diagnostic and management issues.  Your recent event had features of both syncope as well as a seizure/ convulsion. So what in your history points towards syncope?
PRODROMAL FEATURES: meaning things which you felt prior to passing out. You felt light headed, your vision was blurred/ tunneled/ kept going in and out (it always fascinates me how patients use different words to describe the same symptom). Prior to a syncopal event patients may feel as if they are about to pass out/ faint. They may look pale (all the blood was drained out from the face), they may feel/ complain that their legs feel weak/ woobly.
I am uncertain what to make of the staring episodes which followed soon after. By staring do you mean you were unable to concentrate (may occur with syncope) or do you mean you had impairment in your level of consciousness and awareness ( goes more towards a seizure).
Anyways let us move forward. The next thing you remember is waking up in the hospital. From the bystander history, you were noticed to have convulsive movements. During the seizure, you lost body tone leading to a hard fall which cracked open your skull.  During the convulsion itself your eyes rolled back into your head, you foamed from the side of the mouth and bit the side of your tongue. Yes biting the side of the tongue goes more towards a seizure than biting the tip of your tongue. I am not sure who figured that one out though. You did not have loss of bladder control. Post the seizure, you were not yourself  for the next few days with a slow return to the baseline.
There I think I have summarized your history well. Well what happens next? Your history has features of both syncope as well a seizure.  I would have asked a few more questions:
1) did you feel anything prior to the event. We call these auras. Any strange smell, any strange taste and so forth.
2) have you ever had a seizure before.
3) any history of febrile convulsions?
4) are you prone to syncope: were you dehydrated, sick with the flu and so forth.
Well let us move forward. I am taking you step by step as I work through this history. So the doctor ordered an EEG (test to look at the brain waves). Why the EEG? Well simple if the EEG shows abnormal brain waves (I use the word misfiring of the brain), it points towards a seizure. If the EEG is normal, it may point towards syncope. That said and done, patients with seizures may have a normal EEG.
We do not have the EEG results. But during the test you mention something happened to you. Your face started twitching while photic stimulation was been carried out (flashing lights). Your sister has epilepsy and you say her seizures are triggered by flashing lights (usually patients who have primary generalized epilepsy have these kind of seizures).
So where does all this lead to?  My opinion: it is possible you have an underlying seizure disorder.
My recommendations: I would try my level best to rule out or rule in seizures. This may need a longer duration EEG study, if the first one is unrevealing. The decision to start anti-convulsant therapy shall be guided by all the above : history, examination findings, EEG findings and neuroimaging findings (CT scan or MRI brain).
THE BEST PERSON TO MAKE THAT DECISION–YOUR CURRENT DOCTOR AND NOT ME OVER THE INTERNET.  

Is it a seizure or is it syncope? the story continues….

                      Is it a seizure or is it syncope? the story continues….

So our story ended with John in the ER. As many of you rightly guessed the first case scenario represents a typical syncopal episode while in the second case John had a generalized convulsion (seizure).

So what are the points in the history which favor syncope and which favor a seizure?

When a patient presents to a neurologist with an episode of loss of consciousness, it is imperative that we try to elucidate the underlying cause. As you can imagine the treatment of both these conditions is very different.

Syncope (fainting) can come either from the heart (we call this cardiogenic syncope) or from the brain (we call this neurogenic syncope or vasodepressor syncope or more commonly as vasovagal syncope). So for example you can faint (have a syncopal episode) if you have a sudden massive heart attack, or a transient arrhythmia of the heart (the heart beat fluctuates). As you can imagine these are potential lethal causes and hence patient’s who present with syncope are frequently evaluated for these cardiac conditions. Tests like ECG, prolonged 24 ECG (electrocardiogram) and sometimes an echocardiogram are ordered. Vasovagal syncope on the other hand is more benign and our patient John likely had a vasovagal syncopal episode in case scenario No 1. Another classical example of vasovagal syncope is when someone faints when he or she sees blood for the first time (frequently reported in medical students when they go into the OR for the first time).

 So what are the points which favor syncope?

1. Feeling light-headed prior to the episode

2. Feeling dizzy as if you are about to faint.

3. Blurring of vision at the onset of the episode ( Doctor I felt light headed, a little woosy, my vision started to go black and then I passed out)

4. Syncope usually occurs in an upright position (patient is usually standing when it occurs). Syncopal patients usually do not shake (that is they do not have convulsive movements. There is an entity called syncopal convulsion where in the episode starts with a syncope but then goes on to become a seizure. I shall not go into the details here as then it shall become confusing).

5. Usually the loss of consciousness is of very short duration. Once they fall to the ground and the blood rushes to their brain (as gravity has been eliminated), they rapidly regain consciousness.

6. They are not confused after the episode. They come around rapidly and know where they are (they are not confused and disoriented after the episode).

7. Syncopal patients usually do not bite their tongue or have loss of bladder control (wet their patients) during an episode.

What are the points which favor a seizure?

1. Patients who have a seizure do not get the type of prodomal symptoms which patients with syncope do. Meaning they do not feel light-headed, dizzy as if they are about to pass out. Seizures frequently occur out of the blue with no warning whatsoever. That said and done, some patients with seizures which come from the temporal lobe may get an aura. Multiple different types of auras have been reported in temporal lobe epilepsy (smell of burning rubber, metallic taste in the mouth, a rising sensation in the tummy among many others).

2. Seizures can occur in any position-standing, sitting, lying in bed and frequently in sleep too.

3. Patients who have a convulsion shake. We call this tonic clonic movements of the arms and legs (first they are noticed to stiffen up, the eyes may roll up or get deviated to one side and later jerking of the arms and legs occur).

4. The tongue may get caught inbetween the teeth as the patient is stiffening up or when they are having a convulsion (shaking). This frequently leads to a tongue bite (usually on the lateral border of the tongue).

5. When the patient stiffens up, the muscles of the urinary bladder go into a spasm and the patient may end having loss of bladder control (wet their pants). This may also occur when the seizure finally ends and the muscles relax.

6. Frequently patients after a seizure are confused and disoriented for a while. We call this the post ictal state.

7. Seizures frequently lead to loss of muscle tone. The patient falls and hits the ground hard. This may lead to cranio-facial injuries and even fractures. Patients with syncope on the other hand do not fall hard, rather thay seem to ease themselves to the ground.

As you can see now syncope and seizures may resemble each other superficially but a good history is usually able to clarify the diagnosis.

Seizures due to hypoglycemia (low blood sugar)

Seizures in the setting of hypoglycemia are well described. The brain needs sugar to function and when the blood sugar falls “too low”, one of the things that can happen is that the patient may have a seizure (this is usually a generalized convulsion-a tonic-clonic or Grand Mal seizure). There is no one level of blood sugar below which one has a seizure (rather the level varies from person to person). Let me explain that with an example. Lets assume you are a diabetic and you take your insulin shot but for once forget to take a meal (maybe you are a hard working executive on the run). You have a convulsion while at work and are taken to the nearest ER. There your blood sugar at the time of presentation is recorded to be 60 mg/dl. There might be another similar patient whose blood sugar falls to 52mg/dl yet he does not have a convulsion. So there is no set limit below which the brain shall have a seizure but speaking in broader terms usually the brain does not tolerate blood sugar below 60mg/dl and below 40 mg/dl most patients shall be symptomatic (either have a convulsion or be confused and obtunded. The term used for this constellation of neurological signs and symptoms as a result of hypoglycemia is NEUROHYPOGLYCEMIA).

The good news though is that seizures due to hypoglycemia are readily treatable. In the ER we load the patient with glucose (usually this is given via an intravenous drip as the patient is obtunded and confused and cannot accept anything from the mouth). The blood sugar quickly rises and the seizures stop. Patients who suffer from hypoglycemic seizures do not need to be on an anti-epileptic drug. These patients do not have epilepsy. If their blood sugar does not fall down again, they will not have another seizure.

Rather a meticulous search should be conducted to find out the cause of hypoglycemia:

-is the patient a diabetic who took too much insulin by mistake?

 -did he miss his meal but took his insulin?

-is there any other cause of hypoglycemia such an insulin secreting tumor?

-is the patient septic?

Hypoglycemic seizures are most commonly seen in diabetics. This emphasizes the importance of good glycemic control in this vulnerable population.

Nitin Sethi, MD

Seizures in children: febrile convulsions

In this post I would like to talk about seizures in children. Seizures are among the most common conditions for which pediatric neurologists are consulted. Seizures in children differ from seizures in adults. Also the etiology of seizures in children differs from that in adults. There are many epilepsy syndromes which have been described in the pediatric age group, each has its own natural history and prognosis.

Typical febrile convulsion: as the name suggests this is a seizure (convulsion) associated with fever. Febrile seizures/ convulsions are mostly seen in the age group of 6 months to 6 years of age. Classically the child has high fever (may be on account of a sore throat or any other condition), as the fever is rising, the child is noted to have a brief seizure/ convulsion. I used the word brief because in its typical form a febrile seizure is brief lasting for a few seconds to minutes. Also in a typical febrile seizure, the seizure is a generalized tonic clonic seizure (the child stiffens up and then shakes). Typical febrile seizure has a good prognosis and does not lead to epilepsy later on in life. As a result these children need not be treated with anti-epileptic drugs. Children outgrow the seizures after the age of 6 years or so. All we advise parents is to keep the fever down. At times the neurologist might prescribe rectal diazepam. This is marketed under the name Diastat. Rectal diazepam is a benzodiazepine drug which can be given by the rectal route. Parents can give it by themselves, the drug is rapidly absorbed across the rectal mucosa and may abort a prolonged febrile convulsion. Usually febrile seizures run in the family and if a careful history is taken, one finds that one of the child’s parents too had febrile seizures as a child.

Atypical febrile convulsion: a febrile seizure is said to be atypical when either it is very prolonged (remember I said febrile seizures are usually brief) or when it is not generalized but rather focal (one arm or limb shakes not the whole body).  Sometime the seizure may occur without fever or even with temperature less than 100 F. Atypical febrile seizures may lead to epilepsy later in life and hence these children have to be closely followed. If a child has multiple febrile seizures or has a seizure everytime he or she has fever, your doctor may recommend an anti-epileptic drug for a short time. The drug most commonly used in this age group is phenobarbital. Phenobarbital is a safe drug which has been around for awhile now. Its most common side-effect is sedation.

Dr. Sethi