Mini Med Blog #14: Fever – Embrace it, Don’t Fear It!
One of the most common questions that I get from patients is in regards to fevers and when you need to seek out medical care. Before answering that question, let’s review what is an actual fever.
Large scale studies have shown that average oral temperature in the population is 36.8 degrees Celsius (°C). This number was rounded up to give 37 °C as the ‘normal’ temperature. Similarly, fever was observed to be 37.8 °C and it was rounded up to give 38 °C.
Fever = 38 °C (100 °F)
The above is an average and there are slight variations in body temperature from one person to another. Body temperature also varies over the course of a day. It is lowest in the morning and rises by 0.5 °C by early evening. There are other variations based on ethnicity and ovulatory cycles but none have been shown to be clinically relevant.
Oral and rectal digital thermometers are the most accurate method of measuring body temperature. Oral thermometers should be used by all adults and older children who can properly cooperate. Infants and toddlers should use rectal thermometers. Tympanic (ear) and forehead thermometers are not reliable and should be avoided. Axillary (underarm) measurement with a digital thermometer is a less ideal option that can be used in children. If using axillary thermometer, a fever is 37.5 °C.
Is fever dangerous?
No. Fever is the body’s natural response to fighting an infection and does not in itself cause harm. However, fever can cause dehydration and does cause general malaise and this is the main reason why it is commonly treated with Tylenol or Advil. Also, fever is not the same as hyperthermia. Hyperthermia is the rise of body temperature due to external environment factors and can be dangerous. Last, the precise height of the fever is not as important as the duration in determining the seriousness of an infection. A fever of 41 °C x 2 days is less concerning than a fever of 38°C x 5 days.
What is a ‘low grade fever’?
It is a non-specific term that is not used by doctors. It is meant to communicate a temperature between 37 °C and 38 °C lasting greater than 24. It has no clinical value.
How to treat fever?
Both Ibuprofen (Advil) and Acetaminophen (Tylenol) can be used to treat fever. Ibuprofen is superior to Tylenol and should be used unless you have been told to avoid ‘NSAID’ medications. Combining Tylenol with Advil is slightly better than either by themselves but it has a confusing dosing regimen which leads to many medication errors. Ibuprofen dose is 400 mg four times daily. Children dose is 10mg/kg four times daily.
When to seek out medical care?
– Fever ≥ 5 days
– Fever in infants < 3 months old
– Fever in children that are unimmunized/partially immunized
– Fever + Personal history of immunocompromise
– Fever + Cough > 10 days
– Fever + Short of Breath/Difficulty breathing
– Fever + Decrease urine output (dehydration)
– Fever + Confusion and unresponsive
– Fever + Chest Pain
– Fever + Pain when urinating
– Fever + Severe abdominal pain
– Fever + Recent Travel history outside of Canada
The above is not meant to be an exhaustive list and you should always seek care if you are worried about a particular symptom. However, the vast majority of appointments in regards to fever that I see are due to simple viral illness that can be managed at home. Patients have runny nose, cough, and body aches along with a fever. The fever is easily lowered with Advil or Tylenol and patient is drinking and eating well.
How to care for fever at home?
Rest and drink plenty of fluids. Take Advil and Tylenol to lower your temperature. Only return to work and school once fever has completely resolved. That’s it! If you have a short course of fever (< 5days) and are drinking properly, there is nothing else that is required. Allow your body the time it needs to successfully fight the infection.
Keep it Healthy!
Dr. Matin
Here is a link of previous blog posts: https://www.greenbeltfht.com/?cat=23