Post Traumatic Epilepsy: when head trauma leaves behind a seizure disorder

Recently I have seen a few patients with post traumatic epilepsy and hence I decided it might be appropriate to talk about the same in more depth.

Before we begin though I want to wish all the readers of my blog from around the world a very Happy and Healthy New Year 2012. May it bring you not just a healthy brain but also a healthy mind.

Ok now to the topic at hand. Just what do neurologists and neurosurgeons mean when they say you have post traumatic epilepsy? As the name suggests post traumatic epilepsy (PTE) refers to epilepsy/seizures starting after a patient sustains head trauma. Let me explain with an example. Let us assume John is involved in an motor vehicle accident. While driving down the FDR drive late one night he falls asleep behind the wheel of his car. The roads are icy! John’s car spins out of control, jumps the curb and hits an embankment.  John who is not wearing a seat belt gets thrown out of the car striking his head first on the windscreen and then on the unyielding asphalt concrete. A passerby witnesses the accident and calls 911. EMS are on the screen within minutes but John is not moving. His neck is stabilized in a hard collar and he is rushed to the nearest hospital. Glasgow coma scale  (GCS) on arrival is documented to be 5. John is not responding to verbal commands and is rushed to the CT scanner for a stat head CT. CTscan shows all is not well. John has sustained significant head trauma. He has a fracture of the right temporal bone and an underlying epidural hematoma. There are bilateral frontotemporal contusions which are increasing in size. In addition there is diffuse subarachnoid hemorrhage. The epidural hematoma is evacuated that night itself by the neurosurgeon on call. It is decided that at present the frontal lobe contusions be closely observed. John is transferred to the neurological ICU where he is further stabilized. A close watch is kept on the intracranial pressure.

Fast forward 3 weeks.

After a rocky course in the neurological ICU, John makes a remarkable recovery taking the extent of his head injury into consideration. He is discharged from the hospital to a rehab facility skilled in traumatic brain injuries (TBI). In the rehab facility John makes a slow but steady progress. It is 12 noon and John as usual is working with his physical therapist. He suddenly stops what he is doing. Utters a loud guttural sound, falls down to the floor with his eyes rolled up. The therapist notes that he stiffens up for a few seconds and then starts to shake while frothing at the mouth. The whole seizure lasts for about 2 minutes and then subsides on its own. Post seizure John is confused and disoriented but slowly returns to his baseline in about 40 minutes. An appointment is made for John to see Dr. Feelgood a neurologist in the nearby community hospital.

Dr. Feelgood takes a detailed history and then examines John. You have post traumatic epilepsy John, he says and recommends that John consider starting anticonvulsant therapy without further delay.

The scenario I describe above is unfortunately not uncommon in patients who sustain significant head trauma. In fact head trauma is one of the leading causes of epilepsy in men and women below the age of 40 around the world. The human brain is well protected by an extremely rigid skull and so the trauma has to be significant to cause brain damage and resulting PTE.

MINOR BUMPS AND BRUISES TO THE HEAD DO NOT LEAD TO POST TRAUMATIC EPILEPSY. Post traumatic epilepsy is thus very rarely reported after closed head injuries aka concussions such as those sustained on the sport fields(please read my post about concussions either here or on my website http://braindiseases.info). On the other hand PTE is particularly common after penetrating head injuries such as gun shot wounds to the head or when the skull bone is fractured (especially depressed skull fracture where the bone fragment presses on the underlying brain) or when there is significant intracranial bleeding (remember what John’s CT scan showed: blood in the epidural space and hemorrhage into both the frontal and temporal lobes).

Seizures can occur at any time after a significant head injury. The patient may start having seizures immediately after sustaining the head injury. This is called early post traumatic epilepsy and at times this has a more favorable prognosis. After the blood in the brain goes away and the swelling/pressure in the brain subsides, the seizures may also stop spontaneously. Hence these patients may not need to remain on an anticonvulsant medication for a long time. Seizures though have been reported as far out as 5 years after the head injury. This is called late post traumatic epilepsy and these patients usually need to take anticonvulsant medication for a prolonged duration, at times even lifelong.

Depending on the extent of head trauma, seizures may be easy or hard to control in these brain trauma patients. They are usually prescribed anticonvulsant therapy and seizure control is then closely monitored. If seizures persist then a second or third anticonvulsant may be indicated.

Dr. Feelgood started John on a seizure medication by the name of levetiracetam. He advised John to follow up with him after 3 months. On the 3 month follow up visit, John walked into Dr. Feelgood’s office unaided and with a broad smile on his face.

I feel good, Dr Feelgood he said.

Post traumatic epilepsy: a question and an answer

One of the readers of my blog asked me a question regarding her son. I am reproducing her question here. My answer to it follows.

V

my son was involved in a car crash 3 years ago aged 17 years and required brain surgery to remove a bloodclot. He recovered well with no ill effects. He had his first fit in November 2009. He had another 2 that same month. CT and MRI scans clear but eeg showed slight abnomal waves over area of surgery. Neuroligist said our choice if wanted to be on medication. Last fit was 27th November 2009 but he has just had another on 8th February whilst flying to holiday Do you thnk meds should be started to prevent further fits.

Dear V,

                    thank you for writing in to me. Your son’s condition is consistent with what is called post traumatic epilepsy. Let me attempt to explain this a little further. Your son obviously was not born with a seizure disorder (epilepsy). He was apparently well till he was involved in a motor vehicle accident (MVA). As a result of the MVA, he suffered head injury and from what you decribe an intracranial hematoma (blood clot) which required evacuation (removal of the blood clot surgically). He had an uneventful recovery but soon there-after had his first convulsion (you do not mention the time interval between the head trauma and the first convulsion).

As the name suggests post traumatic epilepsy refers to epilepsy/ seizure disorder which occurs after head trauma. Usually for post traumatic epilepsy to occur, the head trauma has to be significant such as a motor vehicle accident with significant intracranial hemorrhage or head injuries sustained in the battle field. Many of our soldiers returning from the battlefields of Afghanistan and Iraq suffer bullet shot injuries to the head (these as you can imagine are penetrating head injuries and cause significant brain damage as the high velocity bullet traverses through the skull). IED (improvised explosive devices) related blast injuries cause closed but still significant head trauma and are the signature injury of these two wars. Many of these brave men and women later develop post traumatic seizure disorder/ epilepsy. In other words minor bumps to the head (example you walk into a door) do not cause post-traumatic epilepsy.

There are three types of post traumatic epilepsy. Immediate, early and delayed. Let me explain this at length. Let us assume you are involved in an accident. Your head strikes the ground or steering wheel hard. You have a seizure soon after the impact. This is called immediate or impact seizure. This type of seizure does not lead to seizures later in life and hence such a patient does not warrant to be on long term anti-convulsant therapy.

Early post traumatic seizures are those which occur within 6 months of injury while late post traumatic seizures are those which occur after 6 months. Remember you can have your first post traumatic seizure as long as 5 years after the head injury. In other words if 18 months go by and the person has not had a seizure then likely he shall not have seizures as a result of head trauma. Patients who have early and late post traumatic epilepsy may warrant treatment with anti-convulsants. This is because the brain has suffered a scar (as a result of the head injury) and it is this scar tissue (consisting of damaged brain tissue) which then misfires and acts as a seizure focus (point in the brain where the seizure originates from).

In the case of your son, since he has suffered multiple convulsions since his head injury, he likely needs to be on an anti-convulsant. This decision though shall be made by his neurologist after consideration of factors which I mentioned earlier in my post. EEG may or may not be helpful in this regard (a normal EEG does not rule out seizure disorder and vice versa not every patient with a seizure disorder has an abnormal EEG).

I hope this is helpful to you. I wish him my very best.

Personal Regards,

Nitin Sethi, MD