Partial seizures are caused by the sudden disorganized firing of electrical signals from one nerve cell to another in one part of the brain. Because the defective signaling is limited to only a part of the brain, these seizures also are called focal seizures.
Depending on the affected part of the brain, partial seizures vary in their effects on the person’s movement, sensation, or behavior. After the seizure is over, the patient may feel confused, weak, or tired. Some patients may be unable to move a part of their body for some time following the seizure. This is called Todd’s paralysis.
Types of partial seizures
Simple partial seizures
Simple partial seizures are limited to one side of the body and are caused by localized defective signaling on one side of the brain. Since the right side of the brain controls the left side of the body and the left side controls the right side of the body, doctors can easily identify the affected part of the brain by observing the side of the body that shows symptoms.
Simple partial seizures do not cause a loss of consciousness; the patient is fully aware during the seizure and remembers it even after the seizure is over.
Simple partial seizures can be categorized into four types depending on symptoms: motor, sensory, autonomic, and psychic.
The motor symptoms affect muscle activity, causing jerking of the arms or legs, and turning of the eyes or head to one side.
The sensory symptoms may affect all five senses (touch, taste, smell, hearing, and sight) causing problems with hearing, unpleasant tastes in the mouth, strange smells, possible hallucinations, a feeling of tingling on one side of the body, and other distortions.
The autonomic symptoms affect parts of the brain responsible for involuntary functions and may cause changes in blood pressure, heart rhythm, and bowel function.
The psychic symptoms affect parts of the brain that control emotions or memory. They may cause feelings of fear, anger, rage, pleasure, anxiety, or “déjà vu” (feeling that an event has occurred before).
Focal impaired-awareness seizures
Focal impaired-awareness seizures, previously known as complex partial seizures, affect a larger area of the brain compared to simple partial seizures. Unlike simple partial seizures, this type of seizure causes a loss of consciousness and the patient does not remember having had a seizure after it is over. A child experiencing a focal impaired-awareness seizure may be awake, but will be unaware of the ongoing seizure.
The symptoms associated with a focal impaired-awareness seizure depend on the part of the brain that is affected. The seizure usually starts with blank staring that may be followed by random movements such as picking up objects, picking at clothes, removing clothes, or chewing. The patient may become angry, yell, scream, sob, or laugh. He or she may start running and appear fearful.
These seizures are preceded by an “aura,” which is a warning symptom of an oncoming seizure. An aura may be manifested in different ways such as a headache, seeing colors, having a funny feeling in the body, or smelling a specific odor.
Jacksonian seizures also may be referred to as “partial seizures that secondarily generalize.” They start as a short partial seizure, which soon becomes generalized. Even though they start in one part of the brain, they spread to other areas, eventually affecting the entire body.
The symptoms first appear as a tingling or twitching sensation in a small area, such as a finger, toe, or corner of the mouth. Since this sensation spreads or “marches” to a larger area of the body, these seizures also are referred to as the “Jacksonian march.”
Managing partial seizures
A patient experiencing a partial seizure should be guided away from hazards and restrained only if their safety is at stake. Any sharp objects near them should be removed to prevent any injuries and the area should be padded with blankets or cushions.
Caregivers should be provided with a seizure management plan to know what to do when the seizure occurs.
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