Friday, March 18, 2011

Medical Myth: High Fever Causes Brain Damage

It is a busy winter evening. The emergency room is full and there are no available beds. I'm in triage, and there are a lot of patients in the waiting room. The secretary approaches me and says a mother would like to talk. I probably have eight patients to triage and she is the last that has checked in. Her child is eighteen months. I feel the tension as I walk to her side of the waiting room. The conversation goes something like this:

"How can I help you?"

"My baby has a fever of 105 degrees."

"Okay, I'm sorry to hear that. Have you given any Tylenol or Motrin?"

"No. Aren't you going to take him right back?"

"No. For one, I don't have any ER rooms open. Let's undress your baby down to his diaper to cool him off. I'll bring you some Motrin and juice to drink to make him more comfortable."

"Did you not hear me? His fever is 105! He's going to get brain damage."

"Ma'am, I understand your concern and I'm sorry your baby is not feeling well but I assure you, he is not going to get brain damage from this fever."

My reassurances do not change her mind. Only when another mother in the ER stands up and says, "No, ma'am, she's right about the fever. Your baby will be fine." does she relent.

In general, fever caused by illness will not cause brain damage. Children can run very high fevers. I've seen up to 106 degrees. We do not thrust them into ice water. We do this instead: undress them, give them some oral fever reducing medicine, and encourage them to drink lots of fluids. Remember, fever is a sign (something measurable) of an illness. Your body does it on purpose to try to kill off bacteria and viruses. The purpose of a fever is to make the host environment (the sick individual) harder for bacteria and viruses to live in. Our main concern in the ER is what is the cause of the fever. This is what we'll worry about. Also, how high the fever is doesn't tell us if the problem is viral or bacterial.

Notice I said fever is not worrisome for brain damage. However, hyperthermia can be very concerning for causing brain damage. Hyperthermia is a rise in body temperature that can overwhelm the body's normal defense mechanisms. Situations like this would include heat emergencies like heat stroke. Think a baby stuck in a locked vehicle. Or, the sweat lodge deaths in Arizona.

Check out these resources for more information, in case you need another "mother" to dispel this myth.




So please, don't perpetuate this myth in your writing, particularly from a character who is a medical person. What are your thoughts?


  1. So glad you posted this. It's information that needs to be more broadly disseminated. Thanks.

  2. Thanks Dr. Mabry. I always love it when you stop by!

  3. Thanks, Jordyn. I didn't know that. Once my son's fever spiked and he began hallucinating. Is that a cause for concern?

  4. Are there ever cases of brain damage caused by fever? My husband has a cousin that is mentally impaired and his mother insists that it was because of a 107 degree fever he had when he was a toddler. That's what the doctors told her. Probably back in 1960s. Maybe it was caused by the infection instead of the fever? Just curious. I'm certainly not going to try and tell her she's wrong.

  5. Sheila and Karen... Thanks so much for your comments.

    Sheila... kids can do funny things when they have high fever. If a parent told me in triage that there child was hallucinating because of fever, no red flags would pop up for me. It is known a child may respond this way to fever. The fever needs to come down with passive cooling (undress, lukewarm washcloths to body, oral fever reducing medicine, and lots of fluids). Fever is a sign of illness. It's the doctor's job to figure out the cause of the fever and determine if it poses a risk to the patient. It's not the fever that's as worrisome as what is causing the fever.

    Karen, as soon as I say that there was never a case of fever related illness that caused brain damage, someone will find some case somewhere that says otherwise. I, personally, in 18 years of nursing have not seen a case of brain damage related strictly to high fever.

    Things that I have seen cause brain damage are: meningitis (bacterial over viral), brain injury from various types of accidents, shaking a child, episodes where a child has been hypoxic (without oxygen) such as nearly drowning, attempting to hang themselves and being revived... etc.

    My guess, in your friend's case, is it was related to the cause of the fever and not the fever itself.

  6. amen and thank you for posting this, our ER's and ped's are overun sometimes with fevers that would be better treated in the comfort of their own home.

  7. You're absolutely right... Mr. or Ms. Anonymous. Thanks for your comment.

  8. I'm so glad I found this! My mother in-law insists that a temp of 104 causes brain damage! I figured that since she's often a spreader of wives' tales, that she was wrong. But it's nice to confirm what is the truth!

  9. The Adams: What a cute couple the two of you are!! How did you find the site?

    Good luck with your mother-in-law. Sometimes, it can be hard to challenge a close family member with strong beliefs.

    Maybe ask her to give you a list of five children she knows personally that have confirmed brain damage just from fever and see if she can think of any.

    Of course, that might make a good scene in a novel as there could be lots of conflict!!

  10. So many new parents need this information, it's common that they think about thier children's mortality and mental health when they are so fragile.

  11. AJ,

    You might be surprised at how truly resilient kids are. Of course, we worry as parents about their health. But, most often, children that present with fever will do really well and recover from their illness.

  12. Hi, I'm 32 yrs old. I went to the rainforest in Guatamala in 1999. In the middle of the night I woke up on the ground delirius and vomiting. I tried calling for help but could barely whisper. I slowly crawled to the only refridgerated unit in the village. It was the sliding glass top kind so I had to climb up and get inside. I don't remember getting out. I have no idea what my temperature was that night but in the morning it was 105.5 and I felt 100% better. So I'm guessing it was pretty bad. For a good three weeks after that everything I saw or heard filled me with disgust and anger. There is also alot of memory loss from before the trip. I then started drinking heavily. Sorry to be such a downer; I'm all better now I think. But if that wasn't some kind of brain damage, I don't know what is. Is there some kind of medical test I should take? Not sure I posted this right so I'll try again. sorry

  13. To Anonymous,

    The reason I'm posting this is because you didn't give me a way to contact you directly.

    I don't give medical advice for "real life" situations. You need to set up an appointment with a trusted, liscenced physician and discuss these concerns with them.

    I wish you the best and hope you find some answers for your concerns.


  14. Hi Jordyn,

    Thank you for the article. My father came down with pneumonia and a high fever which at some point went up to 107 degrees. Because of his complicated situation, his fever lasted for a month until it finally came down to a normal range. He had seizure and was unconscious for a while. Right now he's a very different person. He was caring, loving, cool about everything and down to earth, but right now he's simply rude to everyone, paranoid, depressed, delusional at times. He's lost some memory and he is having trouble remembering new things. The saddest part is seeing how negative he is towards everything knowing he was the most positive person I have ever met in my life. I can't find another reason to explain his change in personality other than the fever. I don't think fever causes brain damage in most cases, but in some cases it possibly can. I am hoping that the damage can be treated and my father recover to his old self. Thanks for listening.

  15. Dear anonymous...

    I don't like to give medical advice here but these symptoms you describe could be the result of other things happening. Personally, I think the seizure and unconsciousness are more likely culprits.

    Point being... I think you need to discuss your concerns with a doctor and get your father a comprehensive physical.

    Blessings to you and your family.


  16. Could you pls post a real peer reviewed reference that concludes that fever over 105 presents no risk? Even the NIH link that you provide IDE disagrees with you. Pls let me know what controlled study proves no ill effect from the brain temp being that high. U can't because there is none. It would be an unethical study. And how would u measure brain damage ESP with respect to personality. I hope that too many kids don't suffer or die because of your condescending and unproven advice. As parents we find out 104 or 105 is not that awful but people like you make it seem we are overreactin when we show appropriate concern.

  17. Dear Anonymous,

    I'm not quite sure what you are reading because the NIH study I refer to and you quote as diagreeing with me states: "Brain damage from a fever generally will not occur unless the fever is over 107.6 °F (42 °C). As goes on to say that fevers related to naturally occurring illness generally tap out around 105.

    In my almost 20 years of nursing-- I have not seen brain damgage related to fever. This is not to say that those things causing the fever (such as meningitis, toxins from certain bacteria) will not cause brain damage. In fact, this is proably the cause and not the fever itself.

    Also, as the article states, high body temperature (not fever) related to hyperthermia (like a baby trapped in a vehicles) is very dangerous and should be treated as an emergency.

    I do think it's reasonable to have a child checked my an MD when they have fever. The purpose of the post is to alleviate the ever present concern of parents that the high fever is going to damage them.

    It won't.

    That's not to say that what is causing the fever might. However, in the vast majority of cases, even the causitive agent of the fever the child is going to weather just fine.

    Again-- this is not a medical advice log. It is for writers.

    So, if your child is sick, have them seen by their doctor.

  18. The word I am reading is "generally" which means that it could. Generally is NOT the same as can or will not. Nowhere in the article does it state that high fever WILL NOT cause damage. Tht is unfounded , and your years of experience are not the same as a long term study. I assume you didn't follow up and test all of the cases of high fever tht you observed short term. This may be for writers but you know that parents search the web seeking advice on whether to take their child to the er. You make it sound obsessive that the mother w an infant w a 105 fever was concerned. Your story only tells me of your lack of compassion, NOT her ignorance.

  19. Dear Anonymous,

    I'm sorry that you feel my offering treatment to this mother and her infant despite the busy condition of the ED at that moment in time was showing a lack of compassion.

    I'm also sorry that parents troll the internet for advice on when they should take their child to the ED. Note the disclaimer on this blog. It is not intended to give medical advice but for writers to use.

    If you think your child is sick then speak to your doctor.

    In all the existence of human illness, do you not think there would be a rash of brain damaged adults since most children run a few high fevers in their life r/t illness? Why is our ED treatment protocol not to thrust them into ice water when the fever is over 104, 105, 106 if it will cause brain damage?

    The fever is not the issue-- it is the cause of the fever. Meningitis, bacterial toxins, septic shock (which can diminish oxygen flow to the brain which is a known cause of brain damage) that acutally does the real damage. That is what we treat-- the root cause.

    Parents focus on the fever because this is what is seen and felt. They are not able to see the damage that, let's say, a bacterial meningitis is doing to their child's brain. This is the devastating insult that caused the trouble.

    I also cannot say the sun will rise tomorrow for certainty but I know it has for the last several millenium.

    Also, I'd be happy to continue to publish your comments if you leave your name.

    Blessings to you.

  20. Ms. Redwood, thank you so much for all your input here. There are bound to be some hysterical parents out there who refuse to believe a medical professional (the same people who think vaccines are dangerous and that all infections can be miraculously cured by antibiotics), so please don't think we are all like that. We are not. Most of us appreciate your medical knowledge, wisdom and experience.