Case Presentation: An 84-year-old Caucasian male presented to the emergency department with a chief complaint of fevers, rigors and altered mental status. On physical exam, the patient was a well-nourished, well-developed male with a fever of 102F. His chest x-ray was clear and free of any infiltrates. His urinalysis was benign with only trace proteins and bacteria. His initial WBC was 13.5, and his serum procalcitonin level was 0.17 ng/mL. His respiratory virus panel was negative, and he had no growth on urine, sputum, or blood cultures.
The patient was initially admitted for sepsis with aggressive fluid resuscitation and empiric antibiotic treatment. Without an identifiable source of infection and continuation of symptoms despite treatment, further investigation was warranted. Additional history revealed that the patient had a long-standing history of essential thrombocytopenia but had started hydroxyurea only one month prior.
At this point, the hydroxyurea was discontinued, and the patient was monitored over the next several days. Without the hydroxyurea, the patient’s fever resolved, and he became symptom free in a few days and was later discharge home.
Discussion: Essential thrombocythemia is a type of myeloproliferative disorder affecting 2 in 100,000 people per year. It is characterized by clonal proliferation of megakaryocytes in the bone marrow and excess platelets in the blood (> 450,000 U/L). Hydroxyurea is a first line treatment for essential thrombocythemia due to its myelosuppressive action, and while hydroxyurea is normally well tolerated, several case reports have described hydroxyurea causing a drug fever.
Conclusions: This case illustrates the rare adverse side effects of fevers and rigors with hydroxyurea treatment. Recognition of these adverse drug effects is imperative when evaluating symptomatology mimicking sepsis to reduce the potential costs of diagnostic tests and to direct proper treatment for the patient.