Normal Body Temperature and the Periodic Fever Syndromes

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Normal Body Temperature and the Periodic Fever Syndromes

Any temperature in the range of 97.0 F to 100.0 F is not generally a cause for concern for healthy individuals. But there is more to autoinflammatory diseases than the body temperature.

For over 100 years, 98.6 degrees F (or 37 degrees C) has been accepted as the standard for a normal body temp. This became the standard after a German physician, Dr. Carl Wunderlich, recorded auxiliary (armpit) temperatures from about 25,000 people in the 1800s. With that data, he concluded that the average temperature was 98.6 degrees F, or 37.0 degrees C.

In 1993, the science of normal body temperatures was again studied using modern methods. In that study, published in the Journal of American Medical Association, researchers determined that 98.2 degrees F is a normal body temperature. But this study went further and studied body temperatures at different times of the day. Researchers concluded that,

37.2 degrees C (98.9 degrees F) in the early morning and 37.7 degrees C (99.9 degrees F) overall should be regarded as the upper limit of the normal oral temperature range in healthy adults aged 40 years or younger…

Normal Body Temperature is Highly Variable

Keep in mind, this number, whether it’s 98.6 or 98.2 degrees F, is just an average. The human body has a wide range that is considered normal and each individual may have their own normal range. Any temperature between 97.0ºF to 99.0ºF (36.1ºC to 37.2ºC) is considered perfectly normal and not a cause for concern by itself. Even temperatures from 96.0 to 97.0ºF are not unusual, especially upon waking in the morning. In that same study that revised Dr. Wunderlich’s normal body temperature, the range of temperatures record for study participants was 96.0ºF to 100.8ºF.

What is Hypothermia?

The National Institutes of Health (NIH) states that any temperature below 95.0ºF (35.0ºC) is considered hypothermia. If you or your child’s temperature gets below 95.0ºF, call your doctor immediately.

What is a Fever?

Most doctors consider anything over 100.4ºF (38.0ºC) to be a fever. Click here to read more about fever ranges, the best way to take a temperature, and what can affect your body temperature.

Feverprints fever syndrome study

The Feverprints study seeks to learn more about normal temperature fluctuations and fevers.

The Feverprints Study – Research You Can Participate in to Advance What is Known about Fevers and Normal Body Temperature

Much more could be learned about fevers and normal body temperatures in humans. Researchers from Boston Children’s Hospital and Beth Israel Deaconess Medical Center, both of which have autoinflammatory disease clinics, are now studying this. Anyone in the U.S. age 7 and older can participate in this study. All you need is the iPhone app, a thermometer, and a couple minutes a day to log your temperature. Click here to learn more about the Feverprints study.

Dr. Hausmann, one of the lead researchers for the Feverprints study said in a recent article in the Wall Street Journal,

We’re making judgments on normal and abnormal temperatures based on information that may be inaccurate. This may lead us to over-treat some patients that don’t need to be treated and to withhold treatment from patients that should be treated.

This study aims to give us more current research and insights for patient care and treatment for the 21st century, especially with the use of digital thermometers and various methods to check a temperature. Read more from Dr. Hausmann here about fevers and the Feverprints study.

In Periodic Fever Syndromes, It’s Not Just a Fever

Patients with periodic fever syndromes report having extreme low and high temperatures. Some report temperatures above 105 degrees F and below 95 degrees F when in flares. Some report the lower temperatures before the flare starts or as the flare is breaking, and some report that the low temperatures happen with and without treatment for the flare. Call your doctor right away if you or your child experience these extreme temperatures, high or low.

However, it’s important to not only focus on the fever in autoinflammatory diseases. Although the fever is easy to measure and document, know that when someone is suffering from a periodic fever syndrome, it’s not just a fever. There is systemic inflammation happening throughout the body and fever is only one symptom of that inflammation. It’s important to include all symptoms in your symptom log for the doctor to evaluation and treat. Click here to learn what is happening internally during an autoinflammatory flare.

When determining when and how to treat a patient with an autoinflammatory disease, the other symptoms, such as pain severity, rashes, or joint swelling and blood test results, such as CRP (C-reactive protein), ESR (erythrocyte sedimentation rate), and SAA (serum amyloid A) also need to be considered. For some, symptoms can come before the fever, or in some without a fever. Without treatment, patients with autoinflammatory diseases can suffer greatly even when they don’t have the medical definition of a fever.

When trying to find a diagnosis and/or discuss treatment with your doctor, make sure you document and discuss with your doctor not just the temperature, but also all symptoms. If you or your child has joint pain, mouth ulcers, rashes, abdominal pain, eye issues, hearing loss, or any other symptoms, these need to be logged and discussed with your doctor as well. A good diagnosis is not made just on the basis of the fever, but by evaluating all symptoms, lab tests, and genetic test results collectively. Likewise, effective treatment cannot be made by focusing solely on the fever.


References

  1. University of Pittsburgh: A critical appraisal of 98.6 degrees F, the upper limit of the normal body temperature, and other legacies of Carl Reinhold August Wunderlich.
  2. WebMD: Normal body temperature
  3. Harvard Health Publications: Normal Body Temperature : Rethinking the normal human body temperature
  4. Medline Plus: Hypothermia
  5. The Atlantic: A Cultural History of the Fever
  6. UpToDate: Patient education: Fever in children (Beyond the Basics)

Photo by Riverlim2006/Bigstockphoto.com

To Medicate or Not to Medicate…

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This photo from a medical book published in 1900 shows a child with Still's disease, also known now as SJIA. Without treatment children with SJIA suffer from severely swollen joints, swollen lymph nodes, pleurisy, and may other systemic inflammatory symptoms. This condition is progressive without targeted treatment that stops the inflammatory process - these medications were not available to this child in 1900. The dotted line shows the extent of the swelling of the liver and spleen.

This photo from a medical book published in 1900 shows a child with Still’s disease, also known now as SJIA. Without treatment, children with SJIA suffer from severely swollen joints, swollen lymph nodes, pleurisy, and many other systemic inflammatory symptoms. The dotted line shows the extent of the swelling of the liver and spleen. This condition can be progressive and even fatal without targeted treatment that stops the inflammatory process; these medications were not available to this child in 1900.

For those newly diagnosed parents: I understand your reluctance to use any more medications than necessary, but let me give you some facts. When a child is newly diagnosed, there is a lot to process with the diagnosis, and a child may not be showing all the symptoms yet that can come with these diseases over time.

Maybe at first without the medicines, the pain isn’t too bad, so you may be asking yourself, “Why put those chemicals into our kids if they can make do without them?” Why? Because chronic inflammation could already be doing damage, and in some cases, it can be permanent. Our kids are tough, and will push through the pain just to have a normal life. If the pain gets so bad that they can’t push through, imagine the damage that has already been done before it gets that severe! Sometimes this damage is irreversible, and can only be repaired surgically.

Some chronic inflammation can be subtle and hard to detect unless the doctor is checking for it, and it can get worse over time or escalate rapidly during a severe attack of symptoms.  Did you know that even vision can be affected in some patients with SJIA if inflammation inside the eye (such as uveitis) is allowed to go untreated?  This is a systemic disease, that can affect internal organs and functions, not just the joints and bones.

I have learned two important things that I wish medical professionals would tell all parents of newly diagnosed systemic juvenile arthritis kids:

1. Research has proven that the sooner and more aggressively you treat the inflammation after initial diagnosis, the less damage that is done to the joints.

2. If the joints are damaged, even if the child goes into remission later, they may still have chronic pain from that damage. Forever.

This means that a decision to avoid medications until the child cannot stand the pain could be sentencing your child to a lifetime of pain, even if you do manage to get the arthritis under control. If your doctor is suggesting certain treatments, they are likely considering starting with medications known to have the most potential benefit, that have been researched, and are approved for pediatric patients. All medications have side effects, but not using these treatments may cause more actual, permanent damage to your child than the side effects of these medications would cause in their body.

It’s no coincidence that the development of newer, stronger medications has been followed by a much lower permanent disability rate among juvenile arthritis kids. I have spoken to adults with juvenile arthritis who wished that they would have had the option to use these stronger medicines, because they are now permanently disabled, or even blind.

 

Jeri Téllez is mom to a child with an autoinflammatory type of arthritis known as systemic onset juvenile idiopathic arthritis (SoJIA or SJIA), also called Still’s disease in adults. SoJIA is just one type of arthritis that can start in childhood. Other forms of juvenile arthritis have an autoimmune cause. All juvenile arthritis types share some similarities in how they can severely affect the children who live with these diseases, making treatment necessary to reduce the inflammation and help prevent long term damage or even death in the case of patients with SJIA.