Complex partial seizures/ temporal lobe epilepsy

One of the most common type of seizures seen in the adult population is what are called complex partial seizures. As the name suggests these are partial seizures  meaning that only a part of the brain has the seizure (remember in generalized seizures the whole brain has the seizure and hence the patient clinically has a convulsion, read my posts on epilepsy and seizures at http://braindiseases.info). Complex partial seizures differ from simple partial seizures. While in simple partial seizures there is no disturbance in the patient’s level of consciousness (the patient is awake and alert), in complex partial seizures there is an impairment in the level of consciousness. The patient may have his or her eyes open but usually is unable to respond or communicate. He may or may not comprehend if you try to speak to him during a seizure episode.

As many of the complex partial seizures arise from the temporal lobes in the brain, epilepsy of this kind is also referred to as temporal lobe epilepsy (TLE). That said and done complex partial seizures may also arise from the frontal lobes. Seizures arising from the frontal lobes can present with bizzare clinical manifestations, patient may become hyperactive during the seizure and have strange bicycling like movements of the legs. Complex partial seizures are at times associated with an aura. A simple way to define aura is what happens usually before the seizure. Prior to the onset of a seizure, the patient may experience gustatory or olfactory auras (smell of burning rubber, metallic taste in the mouth are the different classical auras mentioned in the textbooks of neurology). Other patients may mention they “feel wierd” or “dizzy”. Others mention a rising sensation in the stomach.

During the seizure apart from impairment in the level of consciousness, patients frequently exhibit what we refer to as automatisms. These are semi-purposeful movements. Examples include lip-smacking, chewing movements, tongue protusion, picking at the clothes (semi-purposeful movements of the hands). These patients may or may not have a “convulsion”. If the seizure spreads and becomes generalized then they go into a convulsion (such seizures are referred to as partial with secondary generalization).

If an adult presents with a new onset complex partial seizure, neuroimaging is warranted. This is because a new onset complex partial seizure raises the suspicion for an underlying structural lesion in the brain such as a cyst or a tumor (though I want to emphasize here that the most common cause of new onset seizures in the elderly is vascular, meaning a previous stroke).

Work-up for TLE includes an EEG, if needed a long term EEG recording (we call this a video-EEG study), imaging studies like CT scan (though the study of choice is what is called a MRI scan of the brain done under the epilepsy protocol). Thin slices are taken to look at the temporal lobes and hippocampus to make sure there is no structural lesion there nor is there any evidence for mesial temporal sclerosis (MTS).

There are many effective drugs for complex partial seizures/TLE. The most commonly used are carbamazepine (Tegretol) and oxcarbazepine (trileptal). If the seizures are refractory to medications, these patients can be worked up for epilepsy surgery (see my post on epilepsy surgery at http://braindiseases.info).

Nitin Sethi, MD

Incidental cerebral aneursym on brain imaging: what to do?

At times an incidental cerebral aneurysm is found when neuroimaging is carried out. Let me explain this with an example. You go to your doctor as you have been having headaches or suppose you have a history of migraine, your doctor orders a MRI brain. A  cerebral aneurysm is found on brain imaging.

What to do now is the question?

Does the aneurysm warrant treatment?

If yes what treatment?

To answer the above questions it is essential to first understand the natural history of cerebral aneurysm. An aneurysm is a dilatation of a blood vessel. These dilatations may be congenital (meaning you are born with it) or they may develop later in life due to trauma or turbulent blood flow. Cerebral aneurysms can rupture. When they do rupture they cause bleeding into the brain. This bleeding occurs into the subarachnoid space and hence it is called subarachnoid hemorrhage (SAH). SAH has a high morbidity and mortality and hence it is essential that if an incidental aneurysm is found we should know what to do about it.

Well first the question is whether the aneursym is indeed the cause of the symptom for which the imaging was done in the first place. As I stated earlier, the aneurysm may be entirely unrelated to the headache and may just be an incidental finding.

If the aneursym is incidental then the question is what needs to be done about it. What is the risk that it would rupture and cause hemorrhage? How soon should it be taken care of? Fortunately we now have some answers to the above questions. Studies have shown that the risk of rupture is directly related to the size of the aneurysm. Aneurysms which are small in size, less than 7 mm have a lower risk of rupture as compared to those above 10 mm in size. Hence a small aneurysm may be watched. Your doctor may opt to do nothing apart from recommending that the MRI scan be repeated after 6 months to 1 year. If there is interval increase in size of the aneurysm, then definitive treatment options can be pursued.

For aneuryms which are larger than 10 mm, it is important that they be treated on an urgent basis as the risk of rupture is high. There are different modalities to treat the aneurysm. One may either opt for endovascular coiling (here the skull is not opened, instead the aneurysm is approached via the endovascular route and then thrombogenic coils are placed into the aneurysm. The idea is to thrombose the aneurysm over time and hence to obliterate it). The other more invasive approach is to do a formal surgery, the skull is opened up, the aneurysm is located by the neurosurgeon and then a clip or band is placed across its neck to obliterate it.

Which option should be employed depends upon the aneurysm characteristics. Aneurysms which have a broad neck are difficult to coil, those which are in surgically inaccessible locations are more easy to coil endovascularly.

Hope this helps some of my readers. It is a beautiful Sunday afternoon here in New York City. Time to go for a run.

Personal Regards,

Nitin Sethi, MD

Brain tumors: malignant gliomas

Thank you for sharing your brother’s history with me Franciso, I understand how difficult it must be for you and the entire family. I wish him my very best and please feel free to contact me here if you have any particular questions related to him.

Let me continue a little about the management of brain tumors. Well like I said once we discover a glioma in the brain, we first try to determine its extent in the brain. Tests like CT scan and MRI brain  with contrast (dye) are carried out to determine its boundries. Then the question of staging the tumor arises. At times from the MRI itself one can be reasonably sure that this is a malignant glioma or GBM. GBM is one of the few brain tumors, that can spread to the underside of the brain via the corpus callosum and hence gives rise to what we call a butterfly lesion on the MRI (imagine a butterfly with her wings spread out). GBM usually have a lot of surrounding edema which we can see on the MRI again hinting that is a malignant tumor we are dealing with.

Low grade tumors usually are walled off (encapsulated) and do not much surrounding edema. So the next step is trying to stage the tumor and trying to determine its grade. For this reason at times a brain biopsy is done. At the time of the brain biopsy, a frozen specimen is sent to the lab and if the lab gives its initial impression as a tumor, the surgeon might try to debulk the tumor right then and there (that means at the time of biopsy, try to debulk the tumor. This makes sense because the skull is already open and it avoids a second operation).

There is one issue here which is unique for brain tumors like gliomas. The tumor may have one grade on one side and another grade in a different part of the tumor (meaning one part of the tumor may show grade II and the other grade III. To overcome this problem multiple biopsies are taken from different parts of the tumor. The highest grade found is the final grade given to the tumor).

Like I said earlier depending upon the stage of the tumor and its location, the surgeon may or may not be able to remove the entire tumor.

After the biopsy/ surgery patients undergo rehablitation and are then referred to either radiation oncology for radiation or to an oncologist for consideration of chemotherapy. Most of the times all these facilities are available under one roof in a big hospital.

I shall touch on the finer aspects of radiation and chemotherapy in my next post. Its 7.00 pm sat evening NYC, do not have any major plans but do want to get to the gym at some point. Hope all is well in the big world around me.

Personal Regards,

Nitin

Brain tumors: malignant glioma

Since the diagnosis of Ted Kennedy with a malignant glioma, the focus has again turned to brain tumors. Let me discuss in this post a little about malignant gliomas. Glioma are one of the most common primary brain tumors. They are called gliomas because the tumor arises from the glial cells (the tumor does not arise from neuronal cells, rather from glial cells which form the structural supporting cells in the brain).

The WHO (world health organization) grades gliomas into 4 classes:

1) Grade I and II gliomas: are also what are called low grade gliomas. These are slow growing tumors, usually seen in the younger age groups. As they are slow growing, they are less malignant and compatible with a longer survival. They ususally present clinically with a seizure (when they irritate the underlying brain) or when they grow in size and become large, they present with mass effect (the mass and bulk of the tumor presses on surrounding structures and patients may present with weakness on one side). How are low grade gliomas treated?

Treatment of low grade gliomas; as these tumors are slow growing, they are at times amenable to surgical resection. This is because these tumors are usually well encapsulated and its margins are well defined. So in children or adults, if we catch these tumors in time and if the tumor does not involve the eloquent cortex (parts of the brain which subserve speech, or control the hand and leg movements), one may be able to resect the entire tumor out enbloc. In some patients, that is all what may be needed and we usually like to avoid radiation in children ( since radiation has its own problems and may cause cognitive deficits in the young child later on). You doctor may also put you on an anti-seizure medication for a short while to prevent you from having seizures.

Grade III and IV gliomas: or high grade gliomas. This includes glioblastoma multiforme or GBM. Since these tumors are high grade, they are usually fast growing and invade the surrounding brain tissue. Hence it is impossible to resect the entire tumor out usually. Even if you resect the entire tumor you see macroscopically (that is with the naked eyes), the tumor has already caused microscopic metastasis and spread in the brain. Here in lies the fact why these tumors are so hard to treat and patients usually have a poor prognosis. In the best centers in the world, we treat these tumors with a combination of surgery ( try to debulk the tumor and remove some of it and decrease the pressure in the brain), radiation (you may either radiate just the tumor or irradiate the entire brain to prevent metastatic spread) and chemotherapy. Radiation and chemotherapy may either be used concurrently  to supplement each other or one after the other. Again usually these tumor present at first with seizures and your doctor may start you on an anti-epileptic drug to prevent it.

I shall build on this discussion in my next post. Enjoy the weekend everyone, it is a beautiful day here in NYC.

Personal Regards,

Nitin Sethi, MD

Back pain

Back pain (radiculopathy/ myelopathy)

Back pain is one of the most common conditions for which patients seek a neurologist’s opinion. There can be protean causes of back pain and before we discuss them here, a brief discussion about the anatomy of the spine shall serve us well.

 

Anatomy of the spine:

The human spinal column is made up of bones called the vertebra stacked one on top of the other (like a column), As the vertebral column is made up of multiple bones articulating with each other, it allows for mobility. We can bend forward (flexion of the spine), arch our back ( extension of the spine) and can also flex our spines laterally in both directions (lateral flexion of the spine). The soft cartilagenous tissue found between two vertebral bodies is called an intervertebral disc. The spinal cord is enclosed in this skeleton of vertebral bones and thus is protected from injury. From the sides of the vertebral bodies the nerve roots come out. These are the roots which later on join to form the big nerves which innervate the muscles of the arms and legs.

 

What is meant by disc herniation?

Other terms used to describe this common condition include “slipped disc” . A herniated or slipped disc refers to the condition where-in the intervertebral disc gets dislodged (herniates out of its right place or slips out of its right place). When the disc herniates out it puts pressure on the nerve roots exiting the spinal cord at that level. Inflammation of the nerve roots results. This can lead to an intense painful condition where-in the patient complains of pain radiating down in the distribution of that nerve root. We in neurology refer to this condition as Radiculopathy.

Depending upon which nerve root is compressed and at which level patients have pain. For example a disc in your neck slips out, you have pain radiating usually into your arms or even into your finger tips, while if a disc in the lower back slips out, patients usually have pain radiating down their leg ( a condition  commonly referred to as sciatica).

Causes of back pain:

As I stated earlier there can be protean causes of back pain. Here I shall list some of the common causes.

1) Slipped or herniated disk.

2) Mechanical trauma to the back resulting in soft tissue injury (injury to the para-vertebral muscles or the soft tissues eg fat).

3) Fracture/ dislocation of the vertebral bodies: sometimes the vertebral bodies may get dislocated or malaligned. One vertebral body may get displaced in relation to the vertebrae below. This condition is referred to as Spondylolisthesis. The vertebral body itself or any of its parts (arch, pedicle) may get fractured resulting in pain. Fractures of the vertebral column can either be traumatic (occuring in the setting of significant trauma) or they can be secondary fractures. Secondary fractures occur when the vertebral body is weakened by an infectious or malignant (cancerous) process.

4) Spondylosis: is one of the most common causes of back and neck pain especially in the middle aged and elderly population. In its most simplistic defination, spondylosis refers to degeneration of the vertebral column. This degeneration of the bones of the spine becomes more apparent as we age, spur formation may occur (osteophytes). These osteophyted may compress the exiting nerve root leading to pain (radicular symptoms). Further on the spinal canal may get narrowed. When this occurs the spinal cord does not have enough space, a condition referred to as spinal canal stenosis. Spinal canal stenosis classically presents with pain which radiates into the buttocks. Patient complains of pain when he walks, with relief of pain on sitting or when he bends forward (flexion). This condition is referred to as neurogenic claudication.

It is important that spinal canal stenosis be diagnosed correctly as it responds to surgical intervention with good relief of pain and discomfort.

 

For one who has conquered the mind, the Supersoul is already reached, for he has attained tranquillity. To such a man happiness and distress, heat and cold, honor and dishonor are all the same

Lord Krishna in the Bhagavad Gita