What is the appropriate management for a 70-year-old patient with leukopenia, neutropenia, and eosinophilia?

Management of a 70-Year-Old Patient with Leukopenia, Neutropenia, and Eosinophilia

Immediate Priority: Rule Out Parasitic Infection Before Any Immunosuppression

This patient requires urgent parasitic workup with three separate concentrated stool specimens for ova and parasites, plus Strongyloides and Schistosoma serology, before any consideration of corticosteroids or immunosuppressive therapy, as undiagnosed strongyloidiasis can cause fatal hyperinfection syndrome if steroids are initiated. 1, 2, 3

The absolute eosinophil count is 0.78 × 10⁹/L (WBC 6.8 × eosinophil% 11.5%), which represents mild eosinophilia (0.5-1.5 × 10⁹/L). However, the neutropenia (absolute neutrophil count 2.43 × 10⁹/L, which is 35.7% of 6.8) combined with eosinophilia creates a concerning pattern that demands systematic evaluation. 2, 4

Critical First Steps in Evaluation

Travel and Exposure History

• Document any travel to tropical/subtropical regions including Southeast Asia, Africa, Central/South America, or Eastern Europe within the past several years, as helminth infections account for 19-80% of eosinophilia cases in returning travelers and can persist for years. 1, 2, 5
• Ask specifically about freshwater exposure in endemic areas (schistosomiasis risk), consumption of raw or undercooked meat/fish/snails/prawns/crabs, and any history of walking barefoot in endemic regions. 1, 2, 5

Medication Review

• Review all current and recent medications, as drug-induced eosinophilia is a common cause in non-endemic areas, and certain medications can also cause neutropenia. 2, 4

Symptom Assessment for End-Organ Damage

• Cardiac symptoms: Ask about chest pain, dyspnea, palpitations, or heart failure symptoms, as eosinophilic cardiomyopathy can be rapidly progressive and life-threatening. 2, 5
• Pulmonary symptoms: Assess for persistent cough, wheezing, or dyspnea, which may indicate eosinophilic lung disease. 1, 2
• Neurological symptoms: Evaluate for peripheral neuropathy, focal deficits, or altered mental status. 1, 2
• Gastrointestinal symptoms: Ask about dysphagia, food impaction, abdominal pain, or diarrhea. 1, 2

Diagnostic Workup Algorithm

First-Line Laboratory Tests

• Three separate concentrated stool specimens for ova and parasites (not just one, as sensitivity is limited with single samples). 1, 2, 5
• Strongyloides serology and culture immediately, as this parasite can persist lifelong and cause fatal hyperinfection syndrome in immunocompromised patients. 1, 2, 3
• Schistosoma serology if any freshwater exposure in endemic areas. 1, 2, 5
• Repeat CBC to confirm persistent eosinophilia and neutropenia. 2, 4

Assessment for End-Organ Damage

• ECG and cardiac troponin to screen for myocardial injury from eosinophilia. 2, 5
• Chest X-ray to identify pulmonary infiltrates. 2, 5
• Peripheral smear to evaluate for dysplasia or abnormal cell morphology that might suggest myeloid neoplasm. 1, 6, 7

If Initial Workup is Negative

• Bone marrow biopsy with cytogenetics if eosinophilia persists >3 months after excluding and treating infectious causes, to evaluate for clonal eosinophilia including PDGFRA/PDGFRB rearrangements. 1, 2, 6
• Molecular testing for FIP1L1-PDGFRA fusion gene, as this predicts response to imatinib. 6, 7

Treatment Algorithm

If Travel History to Endemic Areas (Most Likely Scenario)

Empirical antiparasitic therapy is recommended: 2, 3, 5

• Albendazole 400 mg single dose PLUS Ivermectin 200 μg/kg single dose. 2, 3
• If Schistosomiasis is suspected based on freshwater exposure: Praziquantel 40 mg/kg single dose, repeated at 6-8 weeks. 1, 2, 3
• Repeat CBC 2-4 weeks post-treatment to assess decrease in eosinophil count. 3

Critical Warning About Corticosteroids

Do not initiate corticosteroids before excluding or treating Strongyloides, as steroids can precipitate fatal hyperinfection syndrome in undiagnosed strongyloidiasis. 2, 3, 5

If Parasitic Workup is Negative and Eosinophilia Persists >3 Months

• Refer to hematology for evaluation of primary eosinophilia including hypereosinophilic syndrome or myeloid neoplasm. 2, 6
• If PDGFRA/PDGFRB rearrangement is identified: Imatinib is the treatment of choice. 6, 7
• If hypereosinophilic syndrome is diagnosed (sustained eosinophilia ≥1.5 × 10⁹/L for ≥6 months with end-organ damage): Prednisone 1 mg/kg/day is first-line treatment. 5, 6

Common Pitfalls to Avoid

• Do not assume normal imaging excludes helminth infection, as many parasitic infections cause eosinophilia without radiographic abnormalities, especially in early stages. 3
• Do not rely on a single stool sample, as at least 3 concentrated specimens are required for adequate sensitivity. 1, 2, 5
• Do not wait for symptoms to develop before investigating persistent moderate-to-severe eosinophilia, as end-organ damage can be subclinical initially. 2
• Many helminth-infected patients do not have eosinophilia, so normal eosinophil counts do not exclude parasitic infection in symptomatic patients. 2
• Do not delay cardiac evaluation, as eosinophilic cardiomyopathy can be rapidly progressive. 2, 5

Special Consideration for This Patient's Neutropenia

The combination of neutropenia with eosinophilia raises additional concern for:

• Myeloid neoplasm such as chronic myelomonocytic leukemia (CMML), which can present with dysplasia in multiple cell lines. 1
• Drug-induced cytopenias affecting multiple cell lines. 1, 4
• If neutropenia persists after treating parasitic infection, bone marrow biopsy is indicated to evaluate for myelodysplastic/myeloproliferative neoplasm. 1, 7