What is the management approach for a patient with elevated neutrophil count (neutrophilia)?

Management of Elevated Neutrophil Count (Neutrophilia)

The immediate priority when encountering neutrophilia is to identify and treat bacterial infection, as elevated neutrophils—especially with a left shift—have a likelihood ratio of 7.5 for documented bacterial infection, and band counts >1500/mm³ have the highest likelihood ratio (14.5) for detecting bacterial infection. 1

Initial Clinical Assessment

When evaluating neutrophilia, focus on these specific clinical features:

• Signs of infection: Fever (≥38.3°C single measurement or ≥38.0°C for 1 hour), chills, tachycardia, tachypnoea, hypothermia 2
• Localized infection sites: Oral ulcers, skin infections, abdominal pain/tenderness, respiratory symptoms 1, 3
• Systemic inflammation markers: Altered mental status (hepatic encephalopathy in cirrhosis), shock, renal dysfunction 2
• Specific populations: Hepatosplenomegaly, lymphadenopathy, skin lesions or rashes 1

Diagnostic Workup

Essential Laboratory Tests

• Complete blood count with differential to confirm neutrophilia and assess for left shift (band forms) 1
• Blood cultures (two sets from peripheral vein and any indwelling catheters) before initiating antibiotics 1, 4
• C-reactive protein to assess inflammatory status 1
• Site-specific cultures based on clinical presentation 1

Context-Specific Testing

For patients with cirrhosis and ascites:

• Perform diagnostic paracentesis immediately at hospital admission or with any clinical deterioration (GI bleeding, shock, fever, worsening liver/renal function, hepatic encephalopathy) 2
• Spontaneous bacterial peritonitis (SBP) is diagnosed when ascitic fluid neutrophil count >250/mm³ 2
• Suspect secondary bacterial peritonitis if: multiple organisms on culture, very high ascitic neutrophil count, high ascitic protein, inadequate response to therapy, or localized abdominal signs 2
• Obtain CT scanning promptly if secondary bacterial peritonitis is suspected 2

For patients with pleural effusion:

• Perform diagnostic thoracocentesis with inoculation into blood culture bottles 2
• Spontaneous bacterial empyema diagnosed with: positive culture + >250 neutrophils/mm³, OR negative culture + >500 neutrophils/mm³ (without pneumonia) 2

Management Algorithm

When Infection is Suspected

Initiate empiric broad-spectrum antibiotics immediately—within the first hour—if clinical signs of infection are present. 1, 4

For SBP in cirrhotic patients:

• Start cefotaxime 4 g/day IV (as effective as 8 g/day) for 5 days 2
• Alternative: amoxicillin/clavulanic acid IV then oral (similar efficacy, lower cost) 2
• Avoid aminoglycosides due to nephrotoxicity risk 2

For general bacterial infections with neutrophilia:

• Use broad-spectrum antibiotics covering common pathogens 1
• If monocyte predominance is present, consider intracellular pathogens like Salmonella and adjust coverage accordingly 1

Treatment Duration and Monitoring

• Reassess at 48-72 hours: Check clinical status and laboratory parameters 1
• If afebrile by day 3 with no definite infection site and negative cultures, consider stopping antibiotics after 48 hours of being afebrile 1, 4
• Adjust therapy based on culture results when available 1

Special Populations

Cancer patients with neutrophilia and fever:

• Initiate broad-spectrum antibiotics immediately 1
• Consider G-CSF (filgrastim 5 mcg/kg/day subcutaneously) if documented Grade 3 or higher neutropenia develops 1, 4

Patients with recurrent infections or low IgG:

• Consider immunoglobulin replacement therapy 1

Critical Pitfalls to Avoid

• Never delay antibiotic therapy in symptomatic patients while waiting for culture results 1
• Do not overlook intracellular pathogens when monocytosis accompanies neutrophilia 1
• Always perform paracentesis in cirrhotic patients with ascites before assuming neutrophilia is from another source 2
• Remember that infection signs may be minimal or absent in some neutropenic patients who initially present with neutrophilia before counts drop 4
• Consider non-infectious causes of neutrophilia: surgical stress, systemic inflammation, medications, chronic conditions 1, 5

Risk Stratification by Severity

The severity of neutrophilia correlates with infection risk and clinical course:

• Neutrophil percentage >90% significantly increases likelihood of bacterial infection 1
• Band count >1500/mm³ has the highest predictive value for bacterial infection 1
• The neutrophil-to-lymphocyte ratio reflects severity of systemic inflammation and stress, with marked neutrophilia plus lymphocytopenia indicating more severe clinical course 5