Fever and Low White Blood Cell Count in Children

Fever of unknown origin and leukopenia?

Dear Dr.
Hsiao,
My daughter started having a fever five days ago, with a recorded temperature of 39.7 degrees Celsius.
There were no other obvious symptoms at that time.
We visited a local hospital, where the doctor found signs of tonsillitis during the throat examination.
The physician suggested it might be a common cold.
That evening, she developed nasal congestion, and her fever persisted between 38.0 and 38.7 degrees Celsius (despite taking antipyretic medication).
After three days of continuous fever, we returned to the hospital for further evaluation.
Blood tests and an adenovirus screening were conducted.
The results showed that her white blood cell count was only 2,000, with an effective white blood cell count of just 1,000, and hemoglobin levels were low.
The doctor indicated that this could be virus-related, so she was prescribed antibiotics for three days, with a follow-up blood test scheduled.
Currently, my daughter is still experiencing fever, though it has become milder, averaging around 37.5 degrees Celsius.
She takes antipyretics every six hours.
Last night, she complained of calf pain and walked with a limp.
She also had one episode of diarrhea (semi-liquid).
From midnight to 8 AM, she did not have a fever, with ear temperatures recorded between 36.5 and 36.9 degrees Celsius (measured hourly and documented).
I am concerned that her temperature has not increased.
Could this be due to her low white blood cell count affecting her immune response? Is there a possible connection between her calf pain and the fever? Could there be an issue with her hematopoiesis? What further tests would you recommend?
Thank you for your response, Dr.
Hsiao.
I appreciate your help.
Sincerely,
Shen YS

sys, 50~59 year old female. Ask Date: 2020/06/19

Dr. Xiao Kaiwen reply Pediatrics

1.
The absence of an elevated body temperature is unlikely to be due to a lack of white blood cells for defense: this is not the case, as an increase in body temperature is a function of the thermoregulatory center in the brain.

2.
Muscle soreness in both calves: this is mostly caused by inflammation of the muscles due to certain viral infections, which typically improves gradually over a few days.
Sometimes, blood tests are conducted in the hospital to check for elevated muscle enzymes to confirm this.
3.
Fever combined with a decrease in white blood cells is indeed mostly caused by certain viral infections.
In most cases, this is temporary and does not lead to significant immune deficiency or hematological issues.
Blood tests can be performed a week after the fever subsides to confirm whether white blood cell counts have returned to normal.

Reply Date: 2020/06/19

More Info

Fever in children, particularly when accompanied by a low white blood cell (WBC) count, can be concerning for parents. In your daughter's case, the fever has persisted for several days, and the blood tests indicate a significantly low WBC count, which raises questions about her immune response and potential underlying infections.

Understanding Fever and Low White Blood Cell Count
Fever is a common response to infection, as it is part of the body's immune response. The body raises its temperature to create an environment less favorable for pathogens. In children, fever can be caused by a variety of factors, including viral infections, bacterial infections, and even inflammatory conditions.
A low white blood cell count, particularly a low neutrophil count, can compromise the body's ability to fight infections. Neutrophils are a type of white blood cell that play a crucial role in the immune response, especially against bacterial infections. In your daughter's case, the reported WBC count of 2,000 (with an effective count of 1,000) is significantly below the normal range, which typically falls between 4,000 and 10,000 cells per microliter for children.

Possible Causes of Low WBC Count
1. Viral Infections: Many viral infections can lead to a transient decrease in white blood cell counts. Common viruses that cause such symptoms include adenovirus, influenza, and others. In your daughter's case, the initial diagnosis of a viral infection aligns with this possibility.

2. Bone Marrow Suppression: Conditions that affect the bone marrow's ability to produce white blood cells can lead to low counts. This could be due to infections, certain medications, or underlying health conditions.

3. Autoimmune Disorders: Some autoimmune conditions can lead to a decrease in white blood cells as the body mistakenly attacks its own cells.

4. Nutritional Deficiencies: Deficiencies in essential nutrients, such as vitamin B12 or folate, can also lead to low white blood cell counts.

Management and Next Steps
Given your daughter's symptoms and lab results, here are some recommendations:
1. Monitoring: Continue to monitor her temperature and overall condition closely. If her fever persists or worsens, or if she exhibits any new symptoms (such as difficulty breathing, persistent vomiting, or severe lethargy), seek medical attention immediately.

2. Follow-Up Blood Tests: It is crucial to have follow-up blood tests to monitor her white blood cell count and assess whether it is improving. This can help determine if the low count is a transient issue related to the viral infection or if further investigation is needed.

3. Hydration and Nutrition: Ensure she stays well-hydrated and receives adequate nutrition. This is essential for recovery and can support her immune system.

4. Pain Management: For her leg pain, which may be related to muscle inflammation from the viral infection, you can continue to use over-the-counter pain relievers as recommended by her physician.

5. Consultation with a Specialist: If her WBC count remains low or if there are concerns about her overall health, a referral to a pediatric hematologist may be warranted for further evaluation.

Conclusion
In summary, while a low white blood cell count in conjunction with fever can be concerning, many cases are due to viral infections and may resolve with time. Close monitoring, follow-up blood tests, and supportive care are essential. If there are any signs of deterioration or if her symptoms do not improve, do not hesitate to seek further medical evaluation. Your vigilance as a parent is crucial in ensuring her health and well-being during this time.

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