Case Reports

One lab finding, 2 vastly different causes

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► While both of these patients had eosinophilia, their diagnoses ended up being quite different. What is the best approach to the diagnosis and management of eosinophilia in the ambulatory care setting?




A 13-month-old boy who was recently adopted from Ethiopia presented to a primary care physician with a 3-week history of bloody diarrhea accompanied by flatulence and bloating. Stool cultures were positive for Campylobacter and Shigella. He was prescribed azithromycin but saw only moderate improvement. He was then referred to the Infectious Diseases Department. Neonatal, pregnancy, and immunization histories were unknown and a review of systems was unremarkable. On exam, the child looked well; he weighed 9.6 kg (15th percentile), was 69.5 cm long (<3rd percentile), and his head circumference was 45 cm (10th percentile). Head and neck, cardiorespiratory, and abdominal examinations were unremarkable.

A complete blood count (CBC) showed an elevated white blood cell (WBC) count of 26 x 109/L (normal: 4-10 x 109/L) with predominant eosinophilia (10.4 x 109/L or 40.1% of WBCs; normal: <0.45 x 109/L or 0%-8%). Hemoglobin and platelets were within normal limits. Stool testing for ova and parasites showed Strongyloides stercoralis larvae. Strongyloides serology was negative and Filaria serology was equivocal.


A 15-year-old boy was assessed for a 3-week history of fever and eosinophilia. He had enlarged cervical lymph nodes, a new rash, and had lost 4 pounds. He denied gastrointestinal symptoms, dyspnea, headaches, or chest pain. His past medical and family histories were unremarkable and he reported no drug use or allergies. He had traveled to Cuba with his family for 15 days 3 months prior to presentation. He recalled diarrhea while traveling, which resolved spontaneously. He and his family had traveled “off the beaten track,” eating foods prepared at local establishments and swimming in local rivers. He received pre-travel immunizations.

On examination, he appeared unwell, though his vital signs were normal. He had diffuse lymphadenopathy and a petechial rash on his chest, back, upper buttocks, legs, and feet. Cardiorespiratory and abdominal examinations were unremarkable. A CBC revealed an elevated WBC count of 76.9 x 109/L with predominant eosinophilia (71.5 x 109/L or 92% of WBCs). Hemoglobin, platelets, electrolytes, and liver function tests were normal. The patient was referred to a tertiary care center and was admitted to the hospital. Stool testing for ova and parasites, as well as serology for parasitic infections, was negative. A bone marrow aspiration and biopsy were performed and revealed the diagnosis of acute lymphoblastic leukemia (ALL).


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