Unexplained Fever: Insights and Recommendations for Patients

Consultation for Fever of Unknown Origin

Hello, doctor.
Recently, from the beginning of this month until now, I have measured my ear temperature to be between 37.1 and 38.5 degrees Celsius (my usual ear temperature is around 36 to 36.2 degrees).
At the beginning of the month, I visited an infectious disease specialist and informed the doctor that I had been experiencing a fever for about a week.
Aside from the fever, I felt slightly unwell and had lower back pain, but I did not have any other obvious symptoms.
The doctor conducted a urinalysis and blood tests and prescribed antibiotics for me to take.
During my follow-up visit, the doctor informed me that there were slight bacteria in my urine, but it was not enough to cause a fever, and the antibiotics should be effective.
The blood tests showed normal inflammatory markers and white blood cell counts.
After taking the antibiotics for 10 days, my body temperature still showed no significant changes (ear temperature around 37.1 to 38.2 degrees).
Additionally, I had a similar situation two years ago, where I had a fever for three months.
At that time, I visited the infectious disease department, as well as the pulmonary medicine, dermatology, and rheumatology departments, but no cause was found.
The doctor eventually told me that about 10% of people do not have a discernible cause.
After three months of fever, I eventually returned to normal.
I would like to ask the doctor the following questions, thank you.

1.
Since the doctor suspected that my ear thermometer might be faulty, I was asked to compare it with the hospital's thermometer, and the difference in measurement was 0.1 degrees.
However, when I used an electronic thermometer to measure my oral temperature at home, there was indeed a difference of about 1 degree (lower) compared to the ear temperature.
Which measurement should I rely on?
2.
Given my current situation, what recommendations do you have, doctor?

ANNA, 30~39 year old female. Ask Date: 2020/01/31

Dr. Hong Yuanbin reply Internal Medicine

Hello,
1.
Regarding body temperature, different devices and measurement sites can yield varying results.
It is advisable to refer to the baseline values provided by the device (usually found in the user manual).
Body temperature should be assessed in relation to these baseline values to determine if there is a fever.
2.
Concerning fever, it is true that some patients may not have an identifiable cause for their fever despite thorough investigations.
However, if the fever has resolved, it is recommended to monitor for any additional symptoms and to undergo regular annual health check-ups to ensure overall well-being.

Thank you for your inquiry.

Reply Date: 2020/01/31

More Info

Understanding unexplained fever can be a complex and frustrating experience for patients. Your situation, characterized by persistent fever ranging from 37.1 to 38.5 degrees Celsius, along with mild symptoms such as fatigue and lower back pain, raises several important considerations.
Firstly, it's essential to recognize that fever is a common response of the immune system to various stimuli, including infections, inflammatory conditions, and even malignancies. In your case, the initial evaluation by an infectious disease specialist, which included urine and blood tests, indicated the presence of some bacteria in your urine, but not at a level that would typically cause significant fever. The normal inflammatory markers and white blood cell count further complicate the picture, suggesting that while there may be an underlying issue, it is not straightforward.

Regarding your questions:
1. Temperature Measurement Discrepancies: The differences in temperature readings between your ear thermometer and oral thermometer are not uncommon. Ear thermometers can be influenced by external factors, such as earwax or improper placement, leading to inaccurate readings. Oral thermometers are generally considered more reliable for core body temperature. Given the discrepancy you've noted (1 degree lower in the oral measurement), it would be prudent to rely on the oral temperature for a more accurate assessment of your fever. Consistency in the method of measurement is key when tracking your temperature over time.

2. Current Recommendations: Given that you have already undergone a thorough evaluation and have been on antibiotics for ten days without significant improvement, it may be time to consider further diagnostic steps. Here are some recommendations:
- Follow-Up with a Specialist: Since your fever has persisted and previous evaluations have not yielded a diagnosis, it may be beneficial to consult with a rheumatologist or an infectious disease specialist again. They may consider additional tests, such as imaging studies (like a CT scan or MRI) or more specialized blood tests (like autoimmune markers or cultures for atypical infections).

- Consider a Fever Workup: A comprehensive fever workup might include tests for conditions like tuberculosis, viral infections, or autoimmune diseases. Sometimes, a repeat lumbar puncture or bone marrow biopsy may be warranted if there is suspicion of hematological issues.

- Monitor Symptoms Closely: Keep a detailed log of your symptoms, including the timing of fevers, associated symptoms, and any changes in your condition. This information can be invaluable for your healthcare provider in determining the next steps.

- Supportive Care: While awaiting further evaluation, ensure you are well-hydrated and consider using antipyretics (like acetaminophen or ibuprofen) to manage your fever and discomfort. Rest is also crucial for recovery.

- Psychological Support: Chronic unexplained symptoms can take a toll on mental health. It may be beneficial to seek support from mental health professionals or support groups for chronic illness, as they can provide coping strategies and emotional support.

In conclusion, unexplained fever can be a challenging condition to navigate. It is essential to maintain open communication with your healthcare providers, advocate for further testing if necessary, and take care of your overall well-being during this process. Remember, while it can be frustrating not to have a clear diagnosis, you are not alone in this experience, and many patients face similar challenges.

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