What is the appropriate management for a patient in their 50s with leukocytosis and neutrophilia without fever?

Management of Leukocytosis and Neutrophilia Without Fever in a Patient in Their 50s

A WBC count of 14,300 cells/mm³ with absolute neutrophil count of 11,097 cells/mm³ warrants a careful assessment for bacterial infection even without fever, as this degree of leukocytosis has a likelihood ratio of 3.7 for underlying bacterial infection. 1

Immediate Diagnostic Evaluation

Assess for Left Shift

• Obtain a manual differential count immediately to assess band forms and other immature neutrophils, as automated analyzers are insufficient for this critical determination. 1, 2
• An absolute band count ≥1,500 cells/mm³ has the highest likelihood ratio (14.5) for detecting documented bacterial infection. 1
• A left shift (percentage of band neutrophils ≥16%) has a likelihood ratio of 4.7 for bacterial infection, even with a normal total WBC count. 1, 2

Search for Occult Infection

The absence of fever does not exclude bacterial infection, particularly in older adults where typical symptoms are frequently absent. 1, 3 Your patient's elevated WBC and neutrophil count indicate high probability of underlying bacterial infection that requires systematic evaluation. 1

Systematic Source Identification

Respiratory Evaluation

• Obtain chest radiograph to evaluate for pneumonia, as leukocytosis has been associated with increased mortality in nursing home-acquired pneumonia. 1, 2
• Consider pulse oximetry if any respiratory symptoms are present. 2

Urinary Tract Assessment

• Do NOT perform urinalysis or urine culture if the patient is completely asymptomatic, as asymptomatic bacteriuria should not be treated. 1
• If urinary symptoms are present (dysuria, frequency, new incontinence, gross hematuria), perform urinalysis for leukocyte esterase and microscopic examination for WBCs. 1
• Only obtain urine culture if pyuria is present (≥10 WBCs/high-power field or positive leukocyte esterase). 1

Abdominal and Other Sources

• Consider CT imaging of chest and abdomen if no obvious source is identified and clinical suspicion remains high for occult infection. 3, 2
• Evaluate for skin/soft tissue infections, intra-abdominal processes, or endocarditis based on clinical context. 3, 2

Management Algorithm

If Infection Source Identified

• Initiate targeted antimicrobial therapy based on the identified source and local resistance patterns. 3
• Limit antibiotic duration to 4-7 days if source control is adequate. 3

If No Source Identified But High Clinical Suspicion

• Consider empiric antimicrobial therapy if the patient has other signs of infection (malaise, confusion, functional decline) or if band count is elevated, given the high likelihood ratio for bacterial infection. 1, 3
• Serial WBC counts are essential to track response to therapy. 3

If Truly Asymptomatic

• Do NOT initiate antibiotics based solely on the elevated WBC count if the patient is completely asymptomatic with no clinical signs of infection. 3
• Additional diagnostic tests may not be indicated in the absence of fever, leukocytosis alone, or specific clinical manifestations of focal infection, as the yield is low. 1
• Monitor closely with repeat CBC in 12-24 hours and reassess for development of symptoms. 1

Critical Pitfalls to Avoid

• Do not dismiss the significance of leukocytosis simply because fever is absent—older adults frequently present with atypical infection manifestations. 1
• Do not treat asymptomatic bacteriuria discovered during workup, as this does not improve outcomes and promotes resistance. 1
• Do not rely on automated differential counts alone—manual differential is necessary to accurately assess band forms. 1, 2
• Recognize that noninfectious causes (stress, medications, smoking, obesity, chronic inflammation) can cause leukocytosis, but these typically do not produce this degree of neutrophilia. 4