How to manage a 74-year-old male with leukocytosis and neutrophilia?

Management of Leukocytosis and Neutrophilia in a 74-Year-Old Male

This patient requires immediate evaluation for bacterial infection, as the WBC count of 13.8 × 10⁹/L with neutrophils of 9.2 × 10⁹/L does not meet the threshold for significant leukocytosis (≥14,000 cells/mm³), but warrants careful clinical assessment for infection, particularly in an elderly individual. 1, 2

Initial Clinical Assessment

Immediately evaluate for signs and symptoms of bacterial infection:

• Fever (temperature ≥38°C or new-onset hypothermia) 1
• Respiratory symptoms (cough, dyspnea, chest pain) suggesting pneumonia 2
• Urinary symptoms (dysuria, frequency, new incontinence) indicating possible UTI 1
• Skin/soft tissue changes (erythema, warmth, purulent drainage) 2
• Altered mental status or delirium (particularly important in elderly patients) 1
• Abdominal pain or gastrointestinal symptoms 2

Obtain a manual differential count to assess for left shift:

• Band neutrophils ≥6% or absolute band count ≥1500 cells/mm³ has the highest likelihood ratio (14.5) for bacterial infection 1, 2
• Neutrophil percentage >90% has a likelihood ratio of 7.5 for bacterial infection 2
• Left shift (≥16% bands) has a likelihood ratio of 4.7 for bacterial infection, even with normal total WBC 1, 2

Diagnostic Algorithm

If fever, left shift, or focal infection signs are present:

• Obtain blood cultures before antibiotics if systemic infection suspected 2
• Perform urinalysis and urine culture if UTI symptoms present (but NOT if asymptomatic) 1
• Order chest imaging if respiratory symptoms exist 2
• Direct imaging studies toward the suspected infection source 2

If no fever, no left shift, and no focal infection manifestations:

• Additional diagnostic tests may not be indicated due to low yield 1
• Consider non-infectious causes of mild neutrophilia 3, 4

Non-Infectious Causes to Consider

Evaluate for common non-malignant etiologies in this age group:

• Recent surgery, trauma, or emotional stress (can double WBC within hours) 3
• Medications: corticosteroids, lithium, beta-agonists, epinephrine 2, 3
• Obesity (BMI >30 associated with chronic mild neutrophilia) 4
• Smoking history 3
• Chronic inflammatory conditions 3
• Asplenia 3

The monocyte count of 1.3 × 10⁹/L is within normal range and does not suggest specific pathology. 5

Red Flags Requiring Hematology Referral

Refer to hematology/oncology if any of the following are present:

• Constitutional symptoms: unexplained fever, night sweats, weight loss, fatigue 3
• Easy bruising or bleeding 3
• Splenomegaly or lymphadenopathy 1
• Persistent leukocytosis without identifiable cause after initial workup 3
• Immature white blood cells (blasts, promyelocytes) on peripheral smear 3

Management Based on Clinical Context

For confirmed bacterial infection:

• Initiate appropriate antimicrobial therapy based on suspected source 1
• Monitor clinical response and WBC trends 1
• Duration of antibiotics guided by specific infection and clinical improvement 6

For asymptomatic mild neutrophilia without infection:

• Repeat CBC with differential in 2-4 weeks to assess persistence 3
• Review medication list and consider obesity as contributing factor 4
• Avoid unnecessary antibiotic treatment based solely on mild WBC elevation 2

Common Pitfalls to Avoid

• Do not overlook infection in elderly patients who may not mount fever response - leukocytosis or left shift alone warrants infection evaluation 1
• Do not screen asymptomatic patients with urinalysis/urine culture - bacteriuria is common in elderly and does not require treatment without symptoms 1
• Do not assume infection automatically - thrombosis, medications, and obesity are common causes of neutrophilia in this age group 5, 4
• Do not delay hematology referral if constitutional symptoms or persistent unexplained leukocytosis present 3