controls how the body moves by sending out small electrical signals through the
nerves to the muscles. Seizures, or convulsions, occur when abnormal signals
from the brain change the way the body functions.
different from person to person. Some people have only slight shaking of a hand
and do not lose
consciousness. Other people may become
unconscious and have violent shaking of the entire
Shaking of the body, either mild or violent, does not always
occur with seizures. Some people who have seizures have symptoms before the seizure (auras) or briefly lose touch with
their surroundings and appear to stare into space. Although the person is
awake, he or she does not respond normally. Afterwards, the person does not
remember the episode.
Not all body shaking is caused by seizures.
Many medical conditions can cause a type of body shaking that usually affects
the hands and head (tremors).
A small number of
people will have only one seizure during their lifetime. A single seizure
usually lasts less than 3 minutes and is not followed by a second seizure. Any
normally healthy person can have a single seizure under certain conditions. For
instance, a sharp blow to the head may cause a seizure. Having one seizure does
not always mean that a serious health problem exists. But if you have a
first-time seizure, you should be checked by your doctor. It is important to
rule out a serious illness that may have caused the seizure. Fever seizures
(febrile convulsions) are the most common cause of a single seizure, especially
in children. For more information, see the topic
Epilepsy is a
nervous system problem that causes seizures. It can develop at any age. For more information, see the topic
A seizure can be a symptom of
another health problem, such as:
Eclampsia is pregnancy-related seizure activity that
is usually caused by high blood pressure. It is a life-threatening condition
for both a mother and her baby (fetus) because during a seizure, the fetus's
oxygen supply is drastically reduced. Eclampsia is more likely to occur after
the 20th week of pregnancy. For more information, see the topic
Preeclampsia and High Blood Pressure During Pregnancy.
Nonepileptic seizure (NES) is a condition that can cause seizure-like activity. NES is
characterized by a loss of or change in physical function without a
central nervous system problem. The loss or change
causes periods of physical activity or inactivity that resemble epileptic
seizures. NES can be related to a mental health problem. The physical
symptoms may be caused by emotional conflicts or stress. The symptoms usually
appear suddenly and at times of extreme emotional stress.