Evaluation for Fever in Adults

By Dr. J. Gnanaraj | Published: Sep 2017 Volume: 6

What is fever?

Fever means elevated body temperature. Fever is defined as temperature that is higher than 100° F (37.8° C) as measured by an oral thermometer or higher than 100.8° F (38.2° C) as measured by a rectal thermometer. The term “fever” is commonly used when a person feels too warm, too cold, or sweaty, but they have not actually measured their temperature.

Although 98.6° F (37° C) is considered normal temperature, body temperature varies throughout the day. It is lowest in the early morning and highest in the late afternoon—sometimes reaching 99.9° F (37.7° C).

Should we worry about fever?

Most of the time temporary elevation of body temperature [100 to 1040 F] is well tolerated by healthy adults. Since fever causes increase in heart rate [by 4 per degree increase] and respiratory rate [by 1 per degree increase] it can cause problems to those with heart or lung disease and people with dementia can have worsening symptoms of their mental status.

On the other hand temperatures above 105.8 0 F or 41 0 C can cause severe damage to all the systems and failure of many organs. Such serious elevation can occur with heat stroke or sever sepsis [malaria / meningitis / urinary tract or other serious infections]. They can also be due to use of illicit drugs and with some anesthesia or anti–psychotic medicines.

What causes fever?

Chemicals called Pyrogens cause fever. Microorganisms produce External Pyrogens and white blood cells can produce Internal Pyrogens due to inflammation. Hence some of the immunological disorders and cancers can produce internal pyrogens. These fevers unlike the one caused by external pyrogens last longer and are usually of lower grade. A low-grade fever is often described as an oral temperature that is above 98.6° F (37° C) but lower than 100.4° F (38° C) for a period of 24 hours.

How do you evaluate fever?

Since most common cause of fever is viral fever which is self-limiting it is good to have a plan for evaluating a fever. The first step is to look for warning signs like the following:

  • A change in mental function, such as confusion
  • A headache, stiff neck, or both
  • Flat, small, purplish red spots on the skin (petechiae), which indicate bleeding under the skin
  • Low blood pressure
  • Rapid heart rate or rapid breathing
  • Shortness of breath (dyspnea)
  • A temperature that is higher than 104° F (40° C) or lower than 95° F (35° C)
  • Recent travel to an area where a serious infectious disease such as malaria is common (endemic)
  • Recent use of drugs that suppress the immune system (immunosuppressants)

If these are not present then there is no need for evaluation for 48 hours. Just symptomatic treatment and rest should suffice. With high grade fever with chills it is important to get blood and urine tests at the time of fever to identify diseases like Malaria early.

If the fever persists for over 48 hours then some blood and urine tests are necessary. This is because some viral diseases including Dengue fever can cause lowering of the platelet count and white blood counts thus predisposing to spontaneous bleeding and dangerous infections. Also, if the fever is due to bacterial infection then a treatment with antibiotics becomes essential.

If the fever persists for over a week and especially more than two weeks then there are many causes of fever that need to be investigated so that appropriate treatment could be given. For example, tests are necessary for conditions like Typhoid fever, tuberculosis, etc.

What are the things that doctor should be told?

It is important to tell the doctors the following:

  • Recent travel to areas with specific infections [for example the recent Dengue fever in Kerala]
  • Whether there is pain in the ear, nose, head, neck, teeth, throat, Chest, abdomen, flank, etc.
  • If you are experiencing nasal congestion, burning micturition, cough, diarrhea, etc.
  • If you have been in contact with someone with an infection, predisposing condition like Diabetes, HIV, immunosuppression, etc.
  • Use of medicines like Steroids

How is fever treated?

The treatment of routine mild fever is usually symptomatic if the cause is not viral. Symptomatic treatment involves medicines like Paracetamol to reduce the fever and intake of plenty of fluids and sufficient rest for the body to recover from the fever.

However high temperatures warrant immediate treatment before the various systems start failing. These are similar to treatment of heat stroke. Use of fan, cold or normal water sponging, lifting the legs to allow more blood supply to the brain are as important as any medical treatment. Plenty of fluids are necessary and salt needs replacement if there is lots of sweating.

gnanaraj Dr. J. Gnanaraj MS, MCh [Urology], FICS, FARSI, FIAGES is a urologist and laparoscopic surgeon trained at CMC Vellore. He has been appointed as a Professor in the Electronics and Instrumentation Engineering Department of Karunya University and is the Director of Medical Services of the charitable organization SEESHA. He has a special interest in rural surgery and has trained many surgeons in remote rural areas while working in the mission hospitals in rural India. He has helped 21 rural hospitals start minimally invasive surgeries. He has more than 150 publications in national and international journals, most of which are related to modifications necessary for rural surgical practice. He received the Barker Memorial award from the Tropical Doctor for the work regarding surgical camps in rural areas. He is also the recipient of the Innovations award of Emmanuel Hospital Association for health insurance programs in remote areas and the Antia Finseth innovation award for Single incision Gas less laparoscopic surgeries. During the past year, he has been training surgeons in innovative gas less single incision laparoscopic surgeries.

Image: A medical/clinical thermometer showing the temperature of 38.7 °C. Source/Author: Menchi. Date: 2005-91-30. Access the original Image information here: https://commons.wikimedia.org/wiki/File:Clinical_thermometer_38.7.JPG

References (click to show/hide)

  1. Available from: http://www.merckmanuals.com/home/infections/biology-of-infectious-disease/fever-in-adults
  2. Available from: http://www.emedicinehealth.com/fever_in_adults/article_em.htm
  3. Available from: http://apps.who.int/iris/bitstream/10665/95116/1/9789241506489_eng.pdf