Febrile seizure with no fever: what to know

Febrile seizures are linked to a raised temperature, often during an infection. If no fever was present or the temperature was checked after the event, the episode may need a different explanation. Possibilities include a first unprovoked seizure, low blood sugar, a medication or substance effect, or an infection affecting the brain. A normal temperature after the event does not settle the diagnosis.

Record what happened before, during, and after the episode. Details such as loss of awareness, stiffening, rhythmic jerking, eye position, breathing changes, injury, recovery time, and any illness can help a clinician distinguish causes.

Protect the person from nearby hazards, place something soft under the head, and loosen tight clothing around the neck. Turn them onto their side when the movements stop or if saliva or vomiting is present. Time the seizure, stay with them, and note the movements. Do not hold them down, put anything in the mouth, or give food, drink, or medicine until they are fully alert.

Arrange prompt medical review after a first seizure or an event that is different from previous episodes. Bring a list of medicines and describe any possible exposure to alcohol, recreational substances, or household products. A clinician may check glucose, examine the nervous system, and decide whether further tests are needed.

Call emergency services if the seizure continues for five minutes, repeats without recovery, causes a breathing problem, occurs in water, or leads to a serious injury. Seek immediate help for a first seizure, persistent confusion, weakness that does not clear, severe headache, stiff neck, a new rash, or unusual drowsiness. These features can signal a serious problem such as meningitis or another condition requiring urgent treatment.

Ask what causes should be considered when there is no fever, whether blood glucose or other tests are appropriate, and how to respond if another seizure occurs. Ask whether any medicine, supplement, missed dose, or substance could have contributed. If alcohol use may be relevant, you can also read about Alcohol Use Disorder and ask for confidential support.