A seizure is a nervous system event, but it’s not always a nervous system emergency. Most seizures last between 30 seconds and two minutes and stop on their own without causing lasting harm. A seizure becomes a medical emergency when it lasts longer than five minutes, when the person stops breathing afterward, or when a second seizure follows immediately. Understanding where that line falls can help you respond correctly, whether you’re managing your own condition or helping someone else.
What Happens in the Brain During a Seizure
A seizure is a burst of uncontrolled electrical activity in the brain. Neurons that normally fire in coordinated patterns suddenly begin firing all at once, disrupting normal brain function. Depending on where in the brain this happens, the effects range from a brief stare or strange sensation to full-body convulsions with loss of consciousness.
Brief seizures, like the typical absence seizures seen in children (lasting 5 to 10 seconds), do not appear to cause brain damage. Longer seizures are a different story. When seizure activity continues without stopping, the brain enters a hypermetabolic state. Neurons become overexcited, and inflammatory signals in the brain ramp up the intensity of the electrical storm. Calcium floods into nerve cells through channels that wouldn’t normally be open, which can injure or kill those neurons. This process is why duration matters so much: the longer a seizure runs, the more opportunity there is for permanent damage.
The Five-Minute Threshold
The medical term for a prolonged, dangerous seizure is status epilepticus. It used to be defined as a seizure lasting 30 minutes or more, but guidelines from the Neurocritical Care Society revised that threshold down to five minutes of continuous seizure activity, or repeated seizures without the person recovering in between. The change reflected a growing recognition that waiting 30 minutes to intervene was too long.
Some laboratory models show permanent neurological damage can begin after 30 minutes of continuous seizure activity. But the five-minute mark is the point at which medical teams treat the situation as an active emergency, because seizures that reach five minutes rarely stop on their own and the risk of harm climbs with every passing minute. The mortality rate for a first episode of status epilepticus is between 16 and 20 percent. When seizures resist initial treatment (called refractory status epilepticus), mortality climbs to 35 to 60 percent.
When a Seizure Requires 911
Not every seizure requires an ambulance. Someone with a known seizure disorder who has a typical, brief seizure and recovers normally may not need emergency services at all. But certain situations change the equation. You should call 911 if:
- The seizure lasts longer than five minutes
- A second seizure follows shortly after the first
- The person has trouble breathing or can’t wake up after the seizure ends
- The person is injured during the seizure
- The seizure happens in water
- The person has never had a seizure before
- The person is pregnant
- The person has diabetes and loses consciousness
- The person has a high fever
A first-time seizure always warrants emergency evaluation, even if it was brief and the person seems fine afterward. The cause could be anything from a one-time provocation (low blood sugar, extreme sleep deprivation) to something more serious like a brain tumor or infection. Diagnosis depends on a detailed history of the event, and the workup typically includes an EEG to measure brain electrical activity and an MRI to look at brain structure. MRI is preferred over CT scans because it can detect small tumors and subtle abnormalities that CT may miss.
Febrile Seizures in Children
Febrile seizures are the most common type of seizure in young children, typically occurring between the ages of 6 months and 5 years when a child has a fever above 100.4°F (38°C). There is no specific temperature that triggers them; every child has a different threshold. These seizures look terrifying to parents but are usually harmless.
Simple febrile seizures are a single episode lasting 15 minutes or less. They don’t cause brain damage and don’t mean a child has epilepsy. Complex febrile seizures are more concerning: they last 15 minutes or longer, involve movements on only one side of the body, or recur within 24 hours. Febrile status epilepticus, where the seizure lasts beyond 30 minutes, is rare but carries more serious risks. As with adults, any febrile seizure lasting longer than five minutes should be treated as an emergency.
What to Do While a Seizure Is Happening
If you’re with someone having a convulsive seizure, the most important thing is to keep them safe from their surroundings. Move sharp objects away, cushion their head if possible, and gently roll them onto their side so saliva or vomit can drain rather than block their airway. Time the seizure from the moment it starts. If you don’t have a clock handy, your best estimate matters more than nothing.
Do not put anything in the person’s mouth. Despite the persistent myth, people cannot swallow their tongue during a seizure, and forcing an object between their teeth risks breaking teeth or injuring your fingers. Do not try to hold the person down or restrain their movements. Stay with them, stay calm, and keep track of how long it lasts.
The Recovery Phase
After a seizure ends, the brain doesn’t snap back to normal immediately. The recovery period, called the postictal state, typically lasts between 5 and 30 minutes but can stretch to hours or, in rare cases, days. During this time, a person may feel confused, drowsy, anxious, or have difficulty speaking. Some people experience temporary weakness on one side of the body. This is normal and expected.
What isn’t normal is a postictal state that looks different from what the person usually experiences after a seizure. If you know someone with epilepsy and their recovery seems unusually prolonged, more confused than typical, or includes new symptoms, that’s a reason for medical attention. Recovery symptoms lasting longer than 24 hours also warrant a call to their healthcare provider. The postictal state itself isn’t the emergency, but changes in its pattern can signal a shift in the underlying condition.