How to manage a patient with elevated leukocyte count, low BUA, and eosinophilia?

Management of Elevated Leukocyte Count with Low Eosinophils

The leukocyte count of 11.57 × 10⁹/L with eosinophils of 0.07 × 10⁹/L represents mild leukocytosis with normal-to-low eosinophil count, requiring assessment for infection, inflammatory conditions, or early myeloproliferative disease, while the BUA value of 0.53 appears to be a laboratory parameter requiring clinical context for interpretation. 1, 2

Initial Diagnostic Approach

Assess the Clinical Context

• Obtain detailed history focusing on:

  • Fever, localizing infectious symptoms (respiratory, urinary, gastrointestinal, skin) 1
  • Recent medication changes within 6 months (drug reactions can cause leukocytosis) 2
  • Constitutional symptoms: fever, night sweats, weight loss (concern for malignancy or systemic disease) 3
  • Splenomegaly or hepatomegaly on examination (raises concern for myeloproliferative neoplasm) 4

• Review the complete blood count differential carefully:

  • Left shift with increased neutrophils suggests bacterial infection 1
  • Lymphocytic predominance suggests viral etiology 1
  • Presence of blasts, immature granulocytes, or basophilia raises concern for hematologic malignancy 4
  • Monocyte predominance may suggest intracellular pathogen like Salmonella 1

Key Laboratory Evaluation

• Peripheral blood smear examination to identify blasts, dysplasia, immature granulocytes, toxic granulation, or atypical cells 4
• Inflammatory markers: ESR and CRP to assess for inflammatory or infectious process 1
• Blood cultures if fever or signs of sepsis are present 1
• Urinalysis and urine culture to exclude urinary tract infection 1

Management Based on Findings

If Infection is Suspected

• Bacterial infection with neutrophilic leukocytosis: Treat with appropriate antibiotics based on source and culture results 1
• Monitor complete blood count to ensure normalization after treatment of infection 1

If No Clear Infectious Etiology

• Repeat CBC with differential in 2-4 weeks to determine if leukocytosis persists 2
• If leukocytosis persists without clear cause:
  • Assess for splenomegaly via physical examination and imaging if indicated 4
  • Consider Philadelphia chromosome testing (BCR-ABL by RT-PCR or FISH) if splenomegaly present or if basophilia, thrombocytosis, or left shift noted 4
  • Immediate hematology referral if blasts are present, splenomegaly is detected, or persistent unexplained leukocytosis continues beyond 4 weeks 4

Regarding the Low Eosinophil Count (0.07 × 10⁹/L)

• This eosinophil count is at the lower end of normal range (normal: 0.05-0.5 × 10⁹/L) 5
• Low eosinophils can occur with acute bacterial infection or corticosteroid use 1
• This finding does NOT suggest parasitic infection, allergic disease, or eosinophilic disorders, which would present with elevated eosinophils 2, 3
• No specific intervention is needed for low-normal eosinophils in this context 2

Critical Red Flags Requiring Urgent Action

• Presence of blasts on peripheral smear: Immediate bone marrow aspiration and biopsy to exclude acute leukemia 4
• Symptomatic leukocytosis with leukostasis (>100 × 10⁹/L with neurologic or pulmonary symptoms): Emergency leukapheresis 4
• Splenomegaly with basophilia and thrombocytosis: Urgent BCR-ABL testing for chronic myeloid leukemia and initiate hydroxyurea for cytoreduction if symptomatic 4
• Signs of sepsis: Immediate broad-spectrum antibiotics and supportive care 1

Common Pitfalls to Avoid

• Do not assume mild leukocytosis is always benign—persistent elevation without clear cause warrants hematology evaluation 4
• Do not overlook medication-induced leukocytosis—review all medications started within the past 6 months 2
• Do not delay peripheral smear examination—automated differentials can miss blasts or dysplasia 4
• Do not attribute leukocytosis to stress or dehydration without excluding other causes through appropriate follow-up 2

Regarding BUA Value

The "BUA" parameter of 0.53 requires clarification of what this measurement represents (possibly bone ultrasound attenuation, blood urea, or another laboratory value). If this represents blood urea or another renal parameter, assess for uremia-related complications, as uremia can affect bone marrow eosinophil homeostasis 6. Correlation with creatinine, clinical context, and other laboratory values is essential for proper interpretation.