Focal or partial epilepsy: causes, symptoms and treatment
We know as "epilepsy" a set of disorders of the nervous system that is characterized by the predisposition to suffer episodes of abnormal brain electrical activity that cause seizures and other symptoms. Sometimes other brain alterations associated with epilepsy also appear, such as a delay in cognitive development.
In this article we will describe the causes, symptoms and treatment of focal or partial epilepsy , the most frequent subtype of this disease, which is defined by the alteration of electrical activity in limited regions of the brain.
- Related article: "Epilepsy: definition, causes, diagnosis and treatment"
What is focal epilepsy?
The different types of epilepsy are differentiated by different clinical dimensions. One of the most relevant is the degree of generalization of electrochemical dysfunction from a cerebral point of view; in this sense the fundamental divergence is the one that occurs between focal or partial epilepsy and generalized epilepsy .
We speak of partial epilepsy when there is a clear predominance of partial seizures. This means that episodes of brain activity dysfunction, the cause of seizures, start in a specific area of the brain, although it can later spread throughout this organ. When this phenomenon occurs we speak of "secondary generalization".
By cons, Generalized epileptic crises or "great evil" affect the entire brain , or a large part of it, from the moment they start. Epilepsy of a generalized type is associated to a greater extent than focal epilepsy to the appearance of the epileptic aura, a set of prodromes that include alterations in sensory perception or psychological confusion.
In the literature we can also find references to the involvement of one of the hemispheres or to both when distinguishing between focal and generalized epilepsy. Loss of consciousness and epileptic aura are more characteristic of generalized seizures, although they can also occur in partial seizures, especially if they affect a broad brain region.
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Symptoms of partial seizures
Sometimes focal epileptic seizures affect the level of alertness, consciousness and memory, and may also influence the observable behavior. In these cases we talk about complex focal or partial crisis , whereas if there are no alterations in memory and consciousness is maintained, they are considered simple focal crises.
Another relevant difference is that the epileptic aura is more frequent in complex crises than in simple crises. The symptoms and signs of focal epilepsy They can also vary greatly depending on the regions of the brain that are affected.
The phenomena associated with partial crises are more common:
- Sudden appearance of intense emotions
- Sensation of nausea
- Sensation of moving or falling to the ground, distorted perception of space
- Sensory alterations and olfactory, auditory, tactile, gustatory and visual hallucinations
- Dissociative phenomena: depersonalization and derealization
- Abnormal muscle contractions
- Behavioral automatisms, for example walking or chewing
- Lateral movements of the eyes, pupillary dilation
- Incrise of cardiac frecuency
- Sweating
- Abdominal pain and discomfort
- Difficulty or inability to speak
further the symptoms depend on the affected brain lobes . If the crisis occurs in the frontal lobe may appear strange movements and difficulties to speak; if in the temporal, fear, automatisms and déjà vu; if in the parietal, tactile sensations and distortions in perception; and if they occur in the occipital, dysfunctions and sensations in the eyes.
As we have said before, some partial seizures extend to the rest of the brain after starting in a specific region of the brain; it is this last aspect that gives them the consideration of focal. The size of the brain area affected by the electrical alteration influences the degree of significance of the symptoms.
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Causes of this type of epilepsy
Partial epilepsy is the most frequent type of this disease . It is especially common in the elderly (around 65 years of age or older), and the presence of cerebrovascular or brain tumor disorders is a very important risk factor.
It is common that focal epilepsy, especially when it begins in adulthood, appears as a result of various factors that damage the brain. Among these Ischemic strokes, traumatic brain injuries , tumors and brain infections. In other cases the cause of focal epilepsy is unknown.
In children it is more common that the cause does not occur as a consequence of factors such as these, but that it is of a primary nature; in these cases we speak of "idiopathic epilepsy". It is worth mentioning the existence of benign focal childhood epilepsy, which is characterized by the presence of focal seizures, by their relative lightness and by disappearing during adolescence.
Treatment of this alteration
Generally, epilepsy, both focal and generalized, is managed by pharmacological treatments. The most common antiepileptic drugs include gabapentin, lamotrigine, topiramate, valproate, and oxcarbazepine. It can also be very useful to adopt a ketogenic diet (low in carbohydrates and rich in proteins) .
In some severe cases of focal epilepsy, it may be advisable to carry out a surgical intervention to prevent major risks or reduce interference in life. This type of surgery consists of remove the part of the brain that is associated with epilepsy so that episodes of dysregulation of brain electrical activity disappear.
However, the variability of the treatments is high; When its manifestation is particularly benign, epilepsy spectrum disorders may not have significant consequences or require any type of treatment.
